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Article

A Study on Outdoor Thermal Comfort During Military Training for College Freshmen: A Survey in a Cold Region of China

by
Hongchi Zhang
1,
Liangshan You
1,
Bingru Chen
1,
Yuqiu Wang
2,
Fei Guo
1,* and
Peisheng Zhu
1
1
School of Architecture and Fine Art, Dalian University of Technology, Dalian 116023, China
2
Dalian Jinpu New Area Federation of Trade Unions, Dalian 116620, China
*
Author to whom correspondence should be addressed.
Buildings 2025, 15(14), 2454; https://doi.org/10.3390/buildings15142454
Submission received: 18 June 2025 / Revised: 9 July 2025 / Accepted: 10 July 2025 / Published: 12 July 2025
(This article belongs to the Section Building Energy, Physics, Environment, and Systems)
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Abstract

College student military training is an organized, high-intensity, short-term militarized activity in China; this study aims to explore the differences in thermal perception between different intensities of military training. Questionnaires and microclimate measurements were conducted during summer military training in cold regions, including the Protective and Rescue Training and Assessment (PRTA), Formation Training (FT), the Shooting and Tactical Training and Assessment (STTA), the Route March (RM), and Dagger Practice (DP). The results indicated that (1) there was no significant correlation between the intensity of the activity and votes on thermal perception. The strongest thermal sensations, the lowest comfort, and the lowest thermal acceptability were experienced during FT, with a lower activity intensity. (2) Air temperature (Ta), globe temperature (Tg), relative humidity (RH), mean radiant temperature (Tmrt), and solar radiation (G) had significant effects on the TSV. (3) FT involved the lowest neutral temperatures (NUTCI/NPET), while DP and RM training had the highest NUTCI and NPET values, respectively. The neutral temperature range during military training was narrower compared to that in other aerobic activities. This study reveals, for the first time, the non-traditional correlation between military training intensity and thermal perception, confirming the specificity of thermal sensations in mandatory training and providing a theoretical basis for optimizing military training arrangements and developing thermal protection strategies.

1. Introduction

Escalating global warming and urbanization have triggered drastic climatic shifts [1], resulting in more frequent heatwaves in urban settings during the summer [2]; this phenomenon has significantly elevated ambient temperatures during outdoor activities [3]. While prolonged outdoor exercise is known to enhance physical endurance, strength, and flexibility and improve psychological well-being, as well as providing stress and anxiety relief through contact with nature [4,5], excessive outdoor activities in hot weather can give rise to severe consequences, such as cognitive impairments and physiological disruptions due to prolonged exposure to high temperatures [6,7,8]. Studies have quantified the correlation between high outdoor temperatures and heat-related illnesses, indicating that for every 1 °C increase in the maximum daily temperature during summer, the incidence rates for heat-related illnesses may rise by 1.20–1.60% [9]. This risk is particularly prominent for high-intensity exercises [10]. Thus, accurately evaluating the thermal benchmark for high-intensity training has become a key factor in ensuring the health of its participants.
Activity intensity plays a crucial role in individuals’ thermal experience [11]. Under varying activity intensities, the human body achieves a state of equilibrium through processes such as vasodilation, vasoconstriction, and perspiration [12], leading to changes in physiological functioning and thermal comfort. Many studies have categorized different types of exercise based on activity intensity and conducted research into thermal comfort in relation to these categories. For example, Lin et al. [13] investigated seasonal variations in thermal perception, thermal comfort, and other influencing factors among individuals participating in various sports in a cold city in China. They observed significant differences in thermal comfort among different types of exercise and that the thermal acceptability ranges for exercisers were greater than those for resting individuals. Moreover, in hot seasons, joggers’ thermal comfort was found to be more influenced by factors such as humidity, wind speed, and solar radiation; Wang et al. [10] examined the impact of three variables—spatial type, exercise intensity, and wet bulb temperature—on the thermal physiology and subjective responses of exercisers. They discovered that exercise intensity exerted the most significant influence on their thermal perception (TSV, TAV), with thermal comfort decreasing as the exercise intensity increased. Conversely, in extremely cold weather, the thermal comfort of individuals engaging in different activities improves with a higher activity intensity [14]. However, most of these studies have focused on ordinary exercise scenarios. Although some studies have investigated different activity intensities in specific populations, such as military personnel [15], outdoor workers [14,16], and athletes [17], these populations differ from the general public. Studies have revealed that such groups exhibit high adaptability and heat tolerance in high-temperature outdoor environments [15,18]. However, research on thermal perceptions during different-intensity exercises among the general public, especially adolescents, remains lacking [19].
Military training, which is widely implemented among adolescents globally, is regarded a compulsory, high-intensity training program aiming to enhance participants’ defense awareness; it includes a wide range of training programs [20]. However, research investigating the thermal perceptions of individuals during military training has been significantly overlooked. Chinese teenagers are required to undergo military training when they enter university, and this training is compulsory and cannot be evaded [19]; additionally, numerous countries worldwide have instituted military training activities for adolescents. In Singapore, male citizens undergo approximately four months of military training during their university years; in South Korea, all physically fit males between the ages of 17 and 24 are conscripted and required to serve in the military [21]. They must undergo 20 days of basic military training before their enlistment, and all male citizens who pass the physical examination are obligated to fulfill their military service [22]; Israel has adopted a system of universal military service, where adolescents aged 14 to 18 receive standardized basic military training within schools, and all young adults, unless they have religious or health reasons for abstaining, must fulfill military service after reaching the age of 18. The majority of high school graduates in Israel engage in military service before pursuing higher education [23,24]; in the United States, students have the opportunity to experience military life through organizations like the Boy Scouts and military summer camps [25]. Furthermore, certain military academies may impose more rigorous training requirements that emphasize not only physical fitness but also the cultivation of skills and leadership abilities [26].
Evidently, military training serves not only to cultivate defense awareness among college students [27] but also to foster physical health, fitness, and teamwork, and enhance students’ emergency response capabilities and awareness of self-protection [27,28]. Although some studies on military activities have focused on the physiological thermal comfort of the training environment [29,30], the training equipment [31], and training apparel [32], research examining the relationship between specific training exercises and thermal comfort is still lacking. In addition, military activities aim to develop military capabilities and combat effectiveness, and their content is more targeted, covering tactics, skills, weapons, and equipment [33]. In contrast, military training primarily consists of basic military instructions and physical fitness training. It can be seen that military training, as a short-term training activity, is mainly aimed towards improving organization and discipline in college students for their adaptation to future life and studies [34]. Furthermore, the distinction between military training and general aerobic exercise lies primarily in the compulsory nature of the former, with the training intensity, duration, organizational methods, and content being standardized and planned. Aerobic training, on the other hand, depends more on individuals’ will and physical state, with relatively short exercise durations and a moderate intensity [35]. Currently, there is a scarcity of studies investigating the differences in thermal perceptions among different military training programs, and a systematic analysis of their thermal benchmarks is even more lacking. Consequently, research and discussions on thermal perceptions during different training exercises within the military training for adolescents are urgently needed. Additionally, existing studies on thermal comfort in military training have predominantly been conducted in hot-summer and warm-winter regions such as Guangzhou [19,36], with relatively limited research on cold regions [30]. Although the thermal stress in cold regions is generally lower than that in southern cities, their summers still experience prolonged high temperatures, which may severely affect outdoor thermal comfort—especially for respondents with a long-term thermal history in cold regions.
Based on this, this study proposes the following questions: (1) Are there differences in the thermal perceptions between adolescent participants engaged in military training programs of different intensities and those performing general aerobic exercises? (2) What are the differences between the thermal benchmarks in military training scenarios and those in other scenarios? The fieldwork was located in Dalian, China. We chose five generic training programs (Protective and Rescue Training and Assessment, Formation Training, Shooting and Tactical Training and Assessment, Route March, and Dagger Practice). Freshmen students from the School of Architecture and Art at Dalian University of Technology were invited as volunteers to participate in this study. Following the conclusion of each training session, the participants were administered post-training questionnaires to assess their thermal perception. Simultaneously, microclimate parameters were recorded to capture the environmental conditions during the military training activities. Through questionnaire surveys and meteorological measurements during various training programs, this study aims to explore the thermal perceptions of students during outdoor training, (1) comparing the variations in thermal perceptions among participants under five different exercise intensities and (2) establishing thermal benchmarks (neutral temperature, the neutral temperature range, thermal acceptability) for distinct activity types within the context of military training. This study, for the first time, quantifies the differences in thermal perceptions among adolescents under mandatory, uniform-intensity training conditions, aiming to fill the research gap on the thermal comfort of adolescent military training and provide a theoretical basis for optimizing military training arrangements and formulating scientific heat protection strategies.

2. Methods

This study adopts a systematic framework of “design–acquisition–analysis–conclusion”, focusing on the differences in thermal perception during military training for college students in cold regions during summer. The specific process is as follows (Figure 1):

2.1. The Study Area

The experiment was conducted at the university campus in Dalian, China. Dalian (38°43′–40°12′ N, 120°58′–123°31′ E) is a famous coastal tourist city in a cold region, located at the southern end of Liaodong Peninsula and surrounded by the sea on three sides. According to the Köppen climate classification [37], it belongs to Dwa, with typical maritime characteristics.
During the experiment, the five military training exercises were designated fixed open sites scattered all over the campus. As shown in Figure 2, the locations were as follows: Fu Jia Football Field (partially shaded by trees, with the majority of the environment exposed to direct sunlight), Western Sports Field (all areas are directly exposed to the sun, without any trees blocking them), Central Sports Field (all areas are directly exposed to the sun, without any trees blocking them), and Metasequoia forest (a large area shaded from the sun, and most of the training is located in the shade of the trees). Meanwhile, the Route March covered various areas on campus, including both shaded and sun-exposed spaces. Fish-eye photos were taken at the measurement points and processed using Rayman 1.2 software to calculate the sky view factor (SVF) values.

2.2. The Experimental Design

2.2.1. Physical Measurements

The investigation was performed for 7 days in September 2023 between the 5th and 15th. Throughout the duration of the survey, various meteorological parameters were measured using instruments, including air temperature (Ta), relative humidity (RH), globe temperature (Tg), wind speed (Va), and solar radiation (G), and recorded every minute. According to the ISO 7726 standard [38], the recommended location for measuring these parameters is the abdominal region, so the measurements were taken at a height of 1.1 m above the ground for each subject. The names and performance parameters of the measuring instruments are listed in Table 1, all in accordance with the ISO 7726 standard [38]. The mean radiant temperature (Tmrt) was calculated using the ISO 7726 standard, using Equation (1) shown below:
T m r t = T g + 273 4 + 1.10 × 10 8 V a 0.6 ε D 0.4 − T a 1 4 − 273
where D is the globe diameter ( D = 0.05 m in this study), and ε is the emissivity (ε = 0.95 in this study).

2.2.2. Questionnaire Surveys

A subjective survey was conducted using an online questionnaire to record the personal information of the participants, including their gender, height, weight, attire, and activity type, as well as their heat symptoms, thermal sensations, thermal comfort, and thermal acceptability. To ensure the validity of the questionnaire, the respondents were trained before conducting the survey. And the reliability and validity of the questionnaire were tested through a pre-experiment. The results showed that the Cronbach’s alpha coefficient was greater than 0.8, indicating that the questionnaire had good internal consistency, so as to ensure the validity and reliability of the data. During intense outdoor training in summer, different heat symptoms can arise. We inquired about whether the participants felt or experienced the following: no symptoms (NO), nausea (NA), headache (HE), restlessness (RE), chest tightness (CT), weakness (WE), stomach upset (SU), dizziness (DI), rapid heartbeat (RH), slight sweating (SS), or profuse sweating (PS). The traditional ASHRAE 7-point scale-rated thermal sensation votes are as follows: −3: cold; −2: cool; −1: slightly cool; 0: neutral; 1: slightly warm; 2: warm; and 3: hot. However, considering the mandatory nature of the student activities during military training, the ASHRAE 7-point scale was expanded to an 11-point scale [39], as follows: −5: unbearably cold; −4: very cold; −3: cold; −2: cool; −1: slightly cool; 0: neutral; 1: slightly warm; 2: warm; 3: hot; 4: very hot; and 5: unbearably hot. The thermal comfort vote (TCV) used a 5-point scale: −2: uncomfortable; −1: slightly uncomfortable; 0: neutral; 1: slightly comfortable; and 2: comfortable. The thermal acceptability vote (TAV) examined the participants’ level of acceptance of the thermal environment, with the following scale: −2: completely unacceptable; −1: unacceptable; 1: acceptable; and 2: completely acceptable. The data collected from the questionnaire was subjected to the statistical analysis and the regression analysis using SPSS Statistics 26.
Due to the confidentiality requirements of military training, access to the questionnaire was prohibited during regular training sessions, so the interviewed students were asked to fill in the online questionnaires at lunchtime and in the evening (at the end of training). The daily military training started at 8:00 am and ended at 17:30 pm, using the school bell as a cue. Each training session had a duration of 45 min, followed by a 5 min break before the subsequent session. A break was taken from 11:30 to 14:00 (Figure 3). The daily training was divided into four time periods: 8:00–9:35, 9:35–11:30, 14:00–15:35, and 15:40–17:30. The respondents were asked to record their thermal perceptions in each period. To ensure the students could recall their subjective feelings during specific time slots and fill out the questionnaire accurately, pre-training was conducted in advance.

2.2.3. Types of Military Training and Metabolic Rate Calculation

In order to investigate the effects of different activity intensities on thermal comfort, this paper classifies student training programs into five types: Protective and Rescue Training and Assessment (PRTA), Formation Training (FT), Shooting and Tactical Training and Assessment (STTA), Route March (RM), and Dagger Practice (DP).
Metabolic Equivalent (MET) is an essential indicator internationally used to define different activity intensities, representing the relative energy metabolism levels and exercise intensity. According to the ASHRAE Handbook, MET refers to the rate at which a person’s metabolic activities convert chemical energy into heat energy and mechanical work. The unit of the skin’s surface area (in meters) is equal to 58.2 W/m2, which is the energy generated by the unit of the surface area of an ordinary person’s skin while sitting still [40]. As the ASHRAE Handbook does not provide specific metabolic rates for military training activities, a time-weighted average metabolic rate approach was utilized to determine the metabolic rates for each training program. Specifically, the training programs were analyzed on an hourly basis, taking into account the proportional contributions of their respective components [40], and the resulting metabolic rates for the respective programs were as follows (Figure 4): PRTA (1.88 MET), FT (2.07 MET), STTA (2.45 MET), RM (2.6 MET), and DP (3 MET). This result differs significantly from that of another study [8] which positioned the activity intensity as light-intensity (sitting, standing, <3 MET), moderate-intensity (walking, 3–6.0 MET), and vigorous-intensity (rope-skipping, >6 MET). The lower metabolic rates observed in this study can be attributed to the calculations of the time-weighted average metabolic rates, which accounted for the composition of the different activities during a training session.

2.3. The Evaluation Indices

The proper selection of thermal comfort indices is crucial for evaluating the thermal comfort of outdoor environments. Studies have identified 165 different heat indices developed worldwide [41], among which the UTCI, PET, predicted mean vote (PMV), and standard effective temperature (SET) are commonly used in the field of thermal comfort [42]. These thermal indices consider the heat exchange between the human body and the thermal environment and are sensitive to variations in environmental parameters [43]. While PET, the PMV, and the UTCI are frequently employed in outdoor thermal perception research due to their broad applicability in thermal sensation and thermal stress classifications, the PET and UTCI are more suitable for outdoor thermal comfort studies compared to PMV [43,44], and their applicability has been validated in cold regions of northern China [45]. The UTCI covers a wider range of climatic regions than other thermal indices and can be applied to a variety of climatic conditions [41]. PET comprehensively considers the major climatic factors and physiological characteristics of the human body affecting thermal comfort [46]. Therefore, in this study, we selected the UTCI and PET as the thermal comfort indices and calculated them using the official website (http://www.utci.org/ accessed on 25 September 2023) and the Rayman 1.2 model, respectively.

2.4. The Statistical Analysis

The meteorological data measured in the field and the content of the questionnaire were collated and analyzed. The Excel and SPSS Statistics 26 were used to calculate the weighted average thermal sensation votes (TSV) on the UTCI and PET at 1 °C intervals. Meanwhile, the MTSV within 1 °C of the UTCI and PET intervals was calculated, and then, linear regressions of the MTSV versus the UTCI and PET were fitted. The neutral temperature and the neutral temperature range for different training programs were determined, and the differences in thermal benchmarks were compared. Additionally, the percentage of thermal discomfort for every 1 °C change in the UTCI and PET was calculated and fitted using polynomial regression to determine the thermal acceptability ranges (TAR) of the respondents. Moreover, a non-parametric Spearman’s correlation analysis was employed to explore the associations between the TSV and meteorological parameters Ta, RH, Va, Tg, Tmrt, and G as a means of exploring the extent to which physical factors influence human thermal perception. In this investigation, all analyses were based on 95% confidence intervals at a significance level of 0.05.

3. Results

3.1. The Descriptive Analysis

3.1.1. The Respondents’ Attributes

A total of 920 valid questionnaires completed by 52 (35%) males and 97 (65%) females were collected, of which 414 were completed by males and 506 by females, all of which were paid questionnaires. All volunteers were freshmen, with an age range of 17–22 years old and a mean age of 19.43 years old. The height range was 157–185 cm, with a mean of 167.23 cm, and the weight range was 47–87 kg, with a mean of 58.95 kg (Table 2). Where BMI refers to body mass index, which is an important standard commonly used internationally to measure the degree of obesity in the human body, the mean BMI value of the respondents was within the normal range (18.5 kg/m2 ≤ BMI < 24 kg/m2). The distribution of the respondents’ information is shown in Figure 5.

3.1.2. The Meteorological Parameters

In this study, the range, mean, and standard deviation for the outdoor meteorological parameters corresponding to each program (including Ta, Tg, RH, Va, Tmrt, and G); the thermal resistance of personal clothing (Iclo); and the thermal indexes (including UTCI and PET) were measured, as shown in Table 3. Among the training programs, PRTA exhibited the highest mean Ta value of 29.87 °C. The DP training showed significantly higher mean Tg (37.30 °C) and Tmrt (40.26 °C) values compared to those for the other training. The mean RH for the RM training reached 68.40%, indicating high outdoor humidity on that day. The DP training had the highest mean Va and G values of 1.44 m/s and 633.87 W/m2. The mean Iclo value was 0.65, which occurred mainly because military training required the students to dress uniformly. The mean UTCI and PET in FT training were both the lowest among the different types of training, at 27.44 °C and 28.11 °C, respectively. The mean PET for PRTA was the highest at 31.99 °C, and the mean UTCI for the RM was the highest at 31.31 °C.

3.1.3. The Distribution of Thermal Symptoms

As analyzed using the questionnaire, the respondents experienced varying degrees of thermal symptoms during the various training sessions, with the type and proportion of their symptoms varying according to the level of activity and the microclimate (Figure 6). During the PRTA, there were relatively high proportions of “slight sweating” (18%), “dizziness” (13%), and “rapid heartbeat” (12%), with only a very small number of people who experienced other thermal symptoms, while 7% had no symptoms. During the FT, there were higher proportions for most of the thermal symptoms, such as “profuse sweating” (35%) and “restlessness” (33%), which were the highest, followed by “weakness” (29%) and “dizziness” (28%). During the STTA, the highest proportions were observed for “profuse sweating” (38%), “weakness” (38%), “dizziness” (35%), and “stomach upset” (32%), likely due to the demanding nature of the activity, involving focused concentration and crawling movements, leading to increased discomfort among the participants. In contrast, the occurrence of heat symptoms was relatively low during the PRTA and RM, with the majority of the participants experiencing “slight sweating” (35%, 37%). In the more intense DP training, 63% of the volunteers reported “profuse sweating”, and 60% experienced a “rapid heartbeat”, along with varying degrees of the other thermal symptoms, reflecting the higher intensity of this training. The DP training exhibited the highest number and proportions of types of thermal symptoms, followed by those for the STTA and FT, while the PRTA and RM caused relatively fewer thermal symptoms. The relatively high proportion of “sweating” and “rapid heartbeat” in all of the training programs was attributed to increased metabolic rates, heart rates, and heat production during outdoor training in the summer months. Sweating is the body’s mechanism of accelerated heat dissipation in hot environments [8]. In summary, the hot outdoor thermal environment poses potential risks during training. The human body maintains its temperature balance by sweating in order to dissipate heat under training conditions. However, when evaporation fails to offset environmental and metabolic heat loads, body temperature rises, leading to additional sweating. The combined stress of hot environments and training content can overload the circulatory system, resulting in feelings of weakness, dizziness, and other issues [19]. Therefore, it is essential to accurately assess outdoor thermal environments during training to reduce the risks associated with heat exposure.

3.1.4. The Thermal Sensation Votes (TSV)

As shown in Figure 7, the TSV for each training program in this survey showed variability. The TSV results for the five types of training are as follows: since the survey was conducted in summer, the vast majority of people felt hot (a TSV ≥ 1) during each training, at 80% (PRTA), 86% (FT), 87% (STTA), 80% (RM), and 87% (DP), respectively. Only a few volunteers felt cold (a TSV ≤ −1), at 5% (PRTA), 3% (FT), 4% (STTA), 6% (RM), and 3% (DP). The instances of feeling cold were primarily concentrated in the evening, possibly due to volunteers sweating after afternoon training sessions, followed by a decrease in activity intensity and a drop in temperature, accompanied by an increased wind speed. Moreover, it was observed that the number of “unbearable heat” votes (TSV = 5, 13%) for the DP training was higher compared to those for the other trainings. This could be attributed to the relatively higher mean values for meteorological parameters such as Tg, Tmrt, and G on the day of the survey, leading to overall stronger thermal sensations among the participants and a preference for selecting the option of extreme heat (a TSV = 5) in relation to other trainings. The PRTA and RM had the highest proportion of “neutral” votes (TSV = 0, 15%). This may be attributed to the lower intensity of these trainings, with the RM training specifically lacking weight-bearing exercises, resulting in a relatively relaxed state among the volunteers.
The reasons for these differences may be that activities such as shooting and individual combat involve movements like crawling and quick stepping, with strictly restricted limb movements. These constraints lead to the superposition of psychological stress and physiological discomfort [47], resulting in obvious sweating in volunteers. In contrast, the PRTA and RM are relatively relaxed, with relatively free training walking rhythms and routes including tree-shaded and ventilated areas. Traditional studies have suggested a linear correlation between exercise intensity and thermal perception, but this study found that the psychological impedance of the mandatory activities with a low degree of freedom (such as FT) amplified thermal discomfort, which is consistent with the conclusion in military training research [15] that “discipline constraints reduce thermal adaptability”.

3.1.5. The Thermal Comfort Votes (TCV)

Figure 8 presents the overall percentage of TCV for the five trainings, revealing notable variations in the TCV among the respondents across different training programs. The most frequent vote category was “neutral” (a TCV = 0, 28.7%), followed by “slightly uncomfortable” (a TCV = −1, 24.7%) and “uncomfortable” (a TCV = −2, 23.8%), while “slightly comfortable” (a TCV = 1, 16.9%) and “comfortable” (a TCV = 2, 5.9%) were less frequent categories. Overall, most of the five trainings made it uncomfortable to be in an outdoor training environment in the summer heat.
In the FT, the STTA, and the DP training, the proportion of volunteers that felt uncomfortable (a TCV ≤ −1) in the hot environment was significantly higher than the proportion that felt comfortable (a TCV ≥ 1), with percentages of 64%, 60%, and 48%, respectively. Although the FT corresponded to the second lowest metabolic rate among the five activity items, the proportion of volunteers who felt uncomfortable during this activity was the highest (a TCV ≤ −1, 64%). This could be attributed to the compulsory activities in FT, such as standing to attention, goose-stepping, and standing still, particularly the requirement to maintain a rigid posture with tight legs, as well as actions involving lifting the hips, tightening the abdomen, and straightening the chest; these movements may have led to symptoms of lower back pain and leg discomfort [47,48], resulting in the lowest level of comfort. Similarly, in the STTA, the perception of lower thermal comfort could be attributed to activities involving crawling and other movements. In the case of the DP training, the higher mean values for meteorological parameters such as Tg, Tmrt, and G may have contributed to the perceived discomfort. In the RM training, the proportions of volunteers that felt uncomfortable (a TCV ≤ −1, 30%) and comfortable (a TCV ≥ 1, 26%) were relatively close, while the highest proportion of the “neutral” category among the five trainings was seen here (a TCV = 0, 44%). This contradicts the expectation for RM training, which involves a higher metabolic rate compared to those in the other trainings, probably due to the fact that RM training is not weight-bearing and does not involve strenuous activities. Additionally, research suggests that the relatively higher air velocity generated during training like the RM, as opposed to more stationary training, enhances evaporative and convective heat loss, offsetting metabolic heat production [10]. In the PRTA, the proportion of participants that felt comfortable (a TCV ≥ 1, 46%) was significantly higher than the proportion that felt uncomfortable (a TCV ≤ –1, 28%). This could be attributed to the nature of protective training, which primarily involves sitting and bandaging without other strenuous activities.

3.2. Outdoor Thermal Benchmarks

3.2.1. Neutral Temperature and Range

Neutral temperature refers to an ambient temperature that is considered comfortable, where individuals feel neither cold nor hot [49]. In this study, the NUTCI and NPET were calculated at various measurement points within the Dalian University of Technology campus. A linear model was employed to estimate the weighted average of the TSV for each 1 °C increase in the UTCI and PET (Figure 9). The findings revealed a strong linear correlation (R2 > 0.7) between the MTSV and the thermal comfort indices examined, with the MTSV increasing as the thermal comfort indices increased. Regarding the relationship between the UTCI and MTSV, the FT and the DP training exhibited the highest slopes of 0.482 and 0.584, respectively, while the RM training had the lowest slope of 0.273. Thus, FT and DP training showed the most significant changes in the MTSV. In terms of PET and the MTSV, DP also displayed the highest slope of 0.526, whereas the RM had the lowest slope of 0.284.
When the MTSV = 0, the corresponding UTCI and PET are neutral temperatures. The NUTCIs for the five activities (PRTA, FT, STTA, RM, and DP) were 25.7 °C, 22.2 °C, 24.3 °C, 25.9 °C, and 26.3 °C, respectively. Among these, DP has the highest neutral temperature; the PRTA and RM have relatively similar neutral temperatures; and FT has the lowest neutral temperature. In terms of PET, the NPET values for the five trainings (PRTA, FT, STTA, RM, and DP) are 27.3 °C, 18.8 °C, 23.2 °C, 27.8 °C, and 26.4 °C, respectively. RM training has the highest neutral temperature, followed by PRTA, DP, and STTA, while FT has the lowest neutral temperature.
When the MTSV falls within the range of −0.5 to 0.5, the corresponding UTCI/PET represents the neutral temperature range [50], representing the range generally accepted by most people. The NUTCIR/NPETR values for the five trainings (PRTA, FT, STTA, RM, and DP) are as follows: 24.2–27.1 °C/25.9–29.6 °C, 21.1–23.2 °C/17.3–20.4 °C, 23.2–25.4 °C/21.7–24.8 °C, 24.1–27.8 °C/26.1–29.4 °C, and 25.5–27.2 °C/25.4–27.3 °C. RM training exhibits slightly wider NUTCIR and NPETR ranges compared to those for the other trainings, with higher upper limits. This indicates that individuals engaged in RM training can tolerate higher temperatures, and the sensitivity of thermal sensation to changes in the UTCI/PET is lower compared to that during other training. Furthermore, the neutral temperature and the neutral temperature range mostly fell below the confidence intervals, which may be attributed to the fact that the majority of respondents voted with a TSV ≥ 1.

3.2.2. Thermal Sensation and Thermal Acceptability

According to ASHRAE 55, the TAR is defined as the range of temperatures that is acceptable to at least 80% (normal conditions) or 90% (strict conditions) of residents [40]. In this study, the temperature range acceptable to 80% of the respondents was utilized. The relationship between the percentage of thermal unacceptability and the thermal indices for each training is illustrated in Figure 10. Due to the survey being conducted in hot summer weather, very few respondents felt cold, as confirmed by the TSVs. This study lacked subjective perceptions related to cold stress (as it only examined a limited range of thermal sensations). Therefore, we calculated the percentage of thermal unacceptability for the UTCI/PET within 1 °C intervals and fitted it to an exponential function [51]. When the percentage of thermal unacceptability was equal to 20%, the upper limit of UTCI/PET acceptability was determined for each training: PRTA (30.7 °C/32.7 °C), FT (25.6 °C/26.1 °C), STTA (28.3 °C/27.4 °C), RM (31.5 °C/31.9 °C), and DP (29.7 °C/29.9 °C); the results showed that the highest acceptable thermal indices for the respondents were the UTCI for the RM (31.5 °C) and the PET for PRTA (32.7 °C), and the lowest acceptable thermal indices were both the UTCI/PET for FT (25.6 °C/26.1 °C). These findings align with the previous results on the TSV and TCV, which indicate that the percentage of respondents that felt hot (TSV ≥ 1) during the PRTA and RM was lower than that in the other trainings, as well as a significantly higher percentage of feeling comfortable (TCV ≥ 1) or neutral (TCV = 0) in TCV than in other activities, whereas FT had a high percentage of thermal sensation and the lowest level of comfort. The reason for this phenomenon may be attributed to the lower actual intensity of the activity in the PRTA and the RM training, while FT involves compulsory activities such as standing to attention, goose-stepping, and standing still. As a result, FT has the lowest thermal acceptability.

4. Discussion

4.1. Factors Influencing Thermal Perception

The diversity of outdoor activities gives rise to varying levels of activity and metabolic rates, which subsequently influence physiological parameters and individual thermal perception. Niu et al. [8] conducted an investigation into the thermal responses associated with different activity intensities (light, moderate, and vigorous). They observed that the MTSV increased as activity intensity heightened within similar spatial environments. Similar results were obtained in another study, Wang et al. [10], focused on three basketball training exercises: shooting (3.7 ± 1.4 MET), layup (5.2 ± 1.4 MET), and full-court dribbling shuttle run (7.2 ± 1.4 MET). It was observed that exercise intensity significantly impacted the TSV and the TAV, with the TSV increasing and the TAV decreasing as the exercise intensity escalated. However, previous studies failed to distinguish the differences between “voluntary exercise” and “mandatory exercise”. Nevertheless, the results of this study did not reveal a strong correlation between activity intensity and thermal perception in military training, as the RM with a higher activity intensity had lower TSV and higher TCV and TAV compared to those for the other trainings, whereas FT, with a lower activity intensity, had higher TSV and the lowest TCV and TAV. We believe that this may be related to the degree of freedom of each program in military training. When training involves dynamic movement (RM) and allows for limited environmental interactions (tree shade, ventilation), the human body can alleviate its thermal load through behavioral regulation (such as adjusting one’s step frequency). In contrast, the static standing (military posture) in FT lacks autonomous regulatory space, leading to psychological impedance and amplifying the thermal discomfort [15], which is consistent with the findings of another study on military training. This study indicates that psychological adaptation, emotional states (positive/negative), and pleasure levels are crucial factors affecting outdoor thermal comfort. Additionally, it may also be influenced by the microclimate conditions of each training project.
Many studies have emphasized that human thermal comfort is highly correlated with the meteorological indicators Ta, RH, Va, Tg, Tmrt, and G [19,52,53]. Fang et al. [19] found that Ta had the most significant effect on TSV, followed by Tmrt, in a survey of university students in Guangzhou assessing their thermal comfort during outdoor training. Liu et al. [53] examined the impact of different meteorological parameters on outdoor thermal comfort in cold regions of China and found that during the autumn and winter seasons, G had the greatest influence on thermal perception, followed by Ta, Va, and RH. This study explores the correlation and degree of influence between various meteorological parameters and TSV in different training programs. The results indicate significant correlations between Ta, RH, Tg, Tmrt, G, and the TSV across the five trainings, with RH exhibiting a significant negative correlation with the TSV. The impact of the meteorological parameters on thermal comfort varies significantly across different training programs. The physical factor with the most significant effect on the TSV for the RM training was Ta (ρ = 0.649), which is in line with most studies, which have concluded that Ta is the physical factor with the greatest effect and highest correlation for outdoor thermal comfort [54,55]. Interestingly, during the PRTA, RH demonstrated the most significant influence on the TSV (ρ = −0.410), contrary to the non-significant impact of RH on thermal perception observed in many studies [45,54]. This discrepancy may be attributed to factors such as coastal climatic conditions, seasonality, or the characteristics of the study population. A study on the outdoor thermal comfort in a park in Dalian also confirms the significant influence of RH on human thermal perception, with an increase in RH leading to decreased TSV among the participants [56]. During FT, Tg exhibited the highest degree of influence on the TSV (ρ = 0.593). In the STTA and the DP training, G demonstrated higher correlations with the TSV compared to those for the other meteorological parameters (ρ = 0.557, ρ = 0.349). Additionally, it was observed that Va had no significant impact on the TSV in any of the trainings except the STTA, possibly due to the minimal fluctuation in the daily mean wind speed during the survey period (Table 4). However, it should be noted that shooting training requires heightened sensitivity, and an increase in wind speed may lead to heightened tension among students, rendering them more sensitive to thermal perception than usual [57].

4.2. Differences in Thermal Benchmarks

By analyzing the data for each student military training program, it can be seen that the slope of the regression model, i.e., the sensitivity of the TSV and the UTCI/PET, for RM training is significantly lower than that for all other trainings, while the sensitivity of DP training is the highest. The NUTCIR and the NPETR for FT are significantly lower than those for the other programs, which indicates that the students’ tolerance of the thermal environment in this program is low, which is because most of the program involves compulsory activities such as standing to attention, goose-stepping, and standing still in FT. Although there is no intense physical exercise involved, the prolonged static posture and muscle tension may lead to discomfort such as backache and leg pain [47,48], consequently influencing the participants’ thermal perception [10]. The upper and lower limits of the NUTCIR and the NPETR in the STTA are similarly biased towards lower values. This may be attributed to the inclusion of actions such as crawling, which are rarely encountered in everyday life and may enhance the students’ discomfort. The upper limit of the NUTCIR and the NPETR for RM training is the highest among the trainings (Figure 8), indicating a higher tolerance for the thermal environment in this training. This can be attributed to the fact that RM training offers more freedom compared to that in other trainings and, unlike previous training sessions, did not involve carrying heavy loads (likely due to considerations regarding the ongoing impact of COVID-19). The NUTCIR values for the PRTA and RM and DP training are relatively high and close to each other, suggesting similar thermal perceptions among the participants.
Interestingly, the present study observed a lack of a linear correlation between activity intensity and thermal perception, which contrasts with existing research findings. Most studies [8,13] have reported a decrease in neutral temperature with increasing activity intensity. This is attributed to the heightened metabolic heat production associated with a higher exercise intensity, leading to an elevated thermal perception among participants. In another investigation of outdoor training and thermal comfort among university students in Guangzhou [58], it was found that the post-training MTSV values significantly increased, while post-training neutral temperature was significantly lower than pre-training neutral temperature. In the current study, the five training programs were determined to have the following metabolic rates: 1.88 MET (PRTA), 2.07 MET (FT), 2.45 MET (STTA), 2.6 MET (RM), and 3 MET (DP). Correspondingly, the ranking of the NUTCI and NPET values was as follows: 22.2 °C (FT) < 24.3 °C (STTA) < 25.7 °C (PRTA) < 25.9 °C (RM) < 26.3 °C (DP) and 18.8 °C (FT) < 23.2 °C (STTA) < 26.4 °C (DP) < 27.3 °C (PRTA) < 27.8 °C (RM). It can be observed that the neutral temperature in the five training activities did not exhibit a decreasing trend with an increasing exercise intensity. For instance, the RM training, which had a higher metabolic rate (2.6 MET), still displayed a relatively high neutral temperature, indicating a higher overall thermal comfort among the students. Conversely, FT, with a lower activity intensity (2.07 MET), exhibited the lowest neutral temperature, suggesting the lowest overall thermal comfort among the participants. Therefore, based on these findings, it can be inferred that defining the metabolic rates for various military training programs based on the normal values is inadequate, necessitating a revision of the metabolic rates associated with these activities.
As evident from Figure 11, the neutral temperature range in this study is noticeably narrower compared to that in previous research, which can be attributed to the higher slope of the linear regression equation between the MTSV and the thermal indices, resulting in a narrower neutral temperature range. Typically, during aerobic activities, the neutral temperature range is wider than that during periods of inactivity. In a study conducted by Niu et al. [8] investigating thermal comfort in outdoor campus settings, it was observed that outdoor activity levels exhibited a significant negative correlation with neutral temperature, indicating that as the activity intensity increased, the neutral temperature decreased, resulting in a lower slope of the regression equation and a broader neutral temperature range. Similarly, Lin et al. [13] found that the thermal acceptability range for individuals engaged in exercise was greater than that for individuals at rest. However, in the context of this study, it was observed that the neutral temperature range during military training was narrower compared to that during general aerobic exercise. This discrepancy may be attributed to the distinct difference in freedom between compulsory and aerobic exercise. Military training programs are mandatory, requiring individuals to adhere to specific arrangements for training, even in the presence of discomfort, with a limited ability to modify their exercise status. Conversely, during aerobic exercise, although its intensity may be high, individuals have the flexibility to self-regulate their activity. Consequently, individuals engaged in compulsory exercise display heightened sensitivity to changes in thermal indices, both psychologically and physiologically.
Compared to a study on outdoor thermal comfort during summer in the same region [51], the NUTCI values for the students engaged in outdoor training in this study were mostly lower than those observed in commercial streets, which can be attributed to the nature of compulsory outdoor training. Conversely, the NUTCI values were generally higher than those in coastal areas, which can be attributed to various factors, such as the microclimatic conditions, characteristics of the surveyed population, spatial morphology, and psychological influences, as consistent with previous research on summer in coastal cities [56]. Additionally, in a summer study conducted in Safidon [59], both the NUTCI and NPET were higher than those in most cities in China. This may be due to the tropical climate of the Indian region, where the air temperature and other climatic parameters are higher, and local residents have a higher adaptability to high temperatures, resulting in a higher neutral temperature. In comparison to other studies on outdoor summer thermal comfort [19,51,55,60,61,62,63,64,65], the neutral temperature in this study was relatively higher. This may be due to the specific characteristics of the study city, as Dalian has a maritime climate, and people have a higher tolerance for its climate compared to that in hot cities. It is also influenced by the study’s geographical location, as the research was conducted in an open playground during summer without obstacles, resulting in generally higher recorded climatic data. Furthermore, the results indicate conflicts among different research methods, highlighting the limitations associated with different methodologies [66].

4.3. Limitations and Prospects

Although this study received support from the United Front Work Department of the university and the School of Architecture and Art and the respondents enthusiastically cooperated in the questionnaire, several limitations still exist. First, this study was conducted during the first freshmen military training activity after the full relaxation of COVID-19 restrictions. Through interviews with the instructors, it was learned that the training intensity requirements for this military training were lower than those in previous years, mainly considering that some people’s physical fitness was relatively weak after the lifting of COVID-19 restrictions. Second, although this study received support from relevant departments, due to the strictness of military training, the measurement instruments could only be placed at the edges of the training ground to avoid interfering with the training, which may have caused errors in the meteorological data. Third, each project in this study was carried out in different activity venues with certain randomness, so spatial environmental variations during the research process may have affected the results. Future research could explore thermal comfort in various open spaces for activities of different intensities. Fourth, this study found significant differences in the acceptance ranges between mandatory exercise and ordinary aerobic exercise, with the former being significantly smaller than the latter. In the future, in-depth analyses on thermal perception and its influencing factors for activity types with different degrees of freedom can be conducted. Fifth, the theoretical model did not incorporate physiological and psychological factors, thermal adaptability, etc. Future research could measure heart rate and skin temperature and explore the influence of physiological and psychological factors on the outdoor thermal perception across different individuals further.

5. Conclusions

In this study, a field survey of outdoor military training for university students was conducted during the summer season in Dalian, China, to obtain the respondents’ thermal perceptions (TSV, TCV, and TAV) of five training programs (PRTA, FT, STTA, RM, and DP), as well as to record microclimate data (Ta, RH, Tg, Va, and G) for the corresponding training. The following results were obtained through the statistical analysis:
(1) The majority of the participants experienced a strong thermal sensation during military training (a TSV ≥ 3). Among them, the highest proportion of extreme thermal sensations was experienced during DP training (a TSV = 5, 13%), while the PRTA and the RM training involved the highest proportions of “neutral” thermal sensations (a TSV = 0, 15%). The FT, the STTA, and the DP training involved significantly higher proportions of discomfort (a TCV ≤ −1) compared to those in the other trainings. The TSV and TCV results for each training corresponded to the occurrence of thermal symptoms. For instance, during DP training, most of the volunteers experienced “profuse sweating” and a “rapid heartbeat”, while FT resulted in higher proportions of various thermal symptoms, such as “profuse sweating”, “restlessness”, “weakness”, and “dizziness”. On the other hand, the PRTA and the RM involved relatively fewer thermal symptoms during training.
(2) The correlation between the TSV and meteorological parameters was explored. It was found that Ta, Tg, RH, Tmrt, and G significantly influenced the TSV for all trainings, while Va only had a significant influence on the STTA. In the PRTA, RH had the most significant impact on the TSV. In FT, Tg had the highest correlation with the TSV. In the STTA and the DP training, G had higher correlations with the TSV compared to those for the other meteorological parameters. In the RM training, Ta had the most significant effect on the TSV. Therefore, for outdoor training, students should avoid exposure to extremely hot outdoor thermal environments without shade for long periods.
(3) Calculations using regression equations for the MTSV and the thermal comfort indices (UTCI, PET) were applied, along with the neutral temperatures and their ranges for the five training programs. The lowest neutral temperature across all activities was observed in FT (22.2 °C/18.8 °C), while the highest NUTCI was recorded in DP (26.3 °C), and the highest NPET was found in both DP and the RM (27.8 °C). In terms of the neutral temperature ranges (NUTCIR/NPETR), FT exhibited a significantly narrower range (NUTCIR = 21.1–23.2 °C, NPETR = 17.3–20.4 °C) compared to those in the other programs, followed by that for the STTA. The highest acceptable thermal indices for the respondents were the UTCI in the RM (31.5 °C) and the PET in the PRTA (32.7 °C), whereas the lowest acceptable indices were both the UTCI/PET in FT (25.6 °C/26.1 °C). Therefore, it is recommended to provide targeted military training arrangements and formulate differentiated thermal protection strategies based on the different training types.
(4) Based on the ASHRAE Handbook, the weighted metabolic rates for the five trainings were calculated. This study found no strong correlation between exercise intensity and thermal perception or the thermal benchmarks for the different activities. The influence of the activity types and their degrees of freedom (mandatory and autonomous) on thermal comfort may surpass that of metabolic rate itself. RM training had a higher activity intensity (2.6 MET) but had a relatively higher thermal comfort compared to those for the other trainings. FT had a lower activity intensity (2.07 MET) but had the lowest thermal comfort among the five trainings. Additionally, the neutral temperature range during military training was significantly narrower compared to that during regular aerobic exercises, indicating that the factors influencing thermal perception and metabolic rate adjustments for mandatory activities should be discussed further and calculated.
This study, distinct from the previous research on thermal comfort during exercise that has centered on activity intensity or environmental factors, reveals for the first time the role of “non-intensity factors” in mandatory training. It provides a theoretical basis for optimizing military training arrangements and formulating differentiated thermal protection strategies, with the aim of reducing the risk of heat-related health hazards and ensuring the normal implementation of outdoor activities.

Author Contributions

Methodology, H.Z.; Software, H.Z. and Y.W.; Formal analysis, H.Z. and L.Y.; Investigation, L.Y., B.C. and Y.W.; Resources, H.Z. and P.Z.; Data curation, L.Y. and B.C.; Writing—original draft, H.Z. and L.Y.; Writing—review & editing, F.G.; Visualization, F.G.; Supervision, F.G.; Project administration, F.G. and P.Z.; Funding acquisition, H.Z. All authors have read and agreed to the published version of the manuscript.

Funding

This study was supported by the National Natural Science Foundation of China (No. 52108044 and No. 52278092).

Institutional Review Board Statement

This study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Review Board (or Ethics Committee) of the Ethics Committee of Dalian University of Technology (protocol code DUTSAFA230823-01 and 2024.05.23) for studies involving humans.

Informed Consent Statement

This study only involved human participation in surveys on outdoor thermal comfort and aimed to investigate subjective information on the participants. This study was an experiment that involved paid questionnaires, and the respondents anonymously filled out the questionnaire without any personal privacy issues. The participants were informed of the relevant information before the questionnaire and were aware of the content and process of the experiment, so there was no informed consent form.

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Conflicts of Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Abbreviations

OTC, outdoor thermal comfort; UTCI, Universal Thermal Climate Index; PET, Physiological Equivalent Temperature; Ta, air temperature (°C); Tg, globe temperature (°C); RH, relative humidity (%); Va, wind speed (m/s); G, global radiation (W/m2); Tmrt, mean radiant temperature (°C); TSV, thermal sensation vote; TCV, thermal comfort vote; TA, thermal acceptability; MTSV, mean thermal sensation vote; NUTCI, neutral UTCI (°C); NUTCIR, neutral UTCI range (°C); NPET, neutral PET (°C); NPETR, neutral PET range (°C); TAR, thermal acceptability range (°C); Clo, clothing insulation; SVF, sky view factor; ASHRAE, American Society of Heating, Refrigerating and Air-conditioning Engineers; Met, activity level; PRTA, Protective and Rescue Training and Assessment; FT, Formation Training; STTA, Shooting and Tactical Training and Assessment; RM, Route March; DP, Dagger Practice; NO, no symptoms; NA, nausea; HE, headache; RE, restlessness; CT, chest tightness; WE, weakness; SU, stomach upset; DI, dizziness; RH, rapid heartbeat; SS, slight sweating; PS, profuse sweating; HR, heart rate.

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Figure 1. Research design and data analysis flowchart.
Figure 1. Research design and data analysis flowchart.
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Figure 2. An overview of the study area.
Figure 2. An overview of the study area.
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Figure 3. Experimental procedure.
Figure 3. Experimental procedure.
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Figure 4. Types of activity and metabolic rate calculation.
Figure 4. Types of activity and metabolic rate calculation.
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Figure 5. Alluvial plot of respondent attributes.
Figure 5. Alluvial plot of respondent attributes.
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Figure 6. Frequency of thermal symptoms.
Figure 6. Frequency of thermal symptoms.
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Figure 7. TSV for each training.
Figure 7. TSV for each training.
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Figure 8. TCV for each type of training.
Figure 8. TCV for each type of training.
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Figure 9. Correlations between MTSV and thermal comfort indices: (A–E) UTCI and (F–J) PET.
Figure 9. Correlations between MTSV and thermal comfort indices: (A–E) UTCI and (F–J) PET.
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Figure 10. The relations between the percentage of unacceptability and each thermal index: (A–E) UTCI; (F–J) PET.
Figure 10. The relations between the percentage of unacceptability and each thermal index: (A–E) UTCI; (F–J) PET.
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Figure 11. NUTCI, NUTCIR, NPET, and NPETR in summer in different climatic regions: (A) UTCI; (B) PET.
Figure 11. NUTCI, NUTCIR, NPET, and NPETR in summer in different climatic regions: (A) UTCI; (B) PET.
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Table 1. Instruments for measuring micrometeorological parameters.
Table 1. Instruments for measuring micrometeorological parameters.
ParameterInstrumentRangePrecisionManufacturer Information
Air Temperature (Ta)HOBO MX2301 −40–0 °C
0–70 °C		±0.25 °C
±0.2 °C		Onset HOBO, Bourne, MA, USA
Relative Humidity (RH)HOBO MX23010–10%
10–90%
90–100% 		±5% RH
±2.5% RH
±5% RH		Onset HOBO, Bourne, MA, USA
Air Velocity (Va)Kestrel 55000.1–9.99 m/s
10.0–20.0 m/s		+(0.05 m/s + 5% readout)
+(5% readout)		Kestrel Meters, Boothwyn, PA, USA
Globe Temperature (Tg)Delta OHM HD 32.3TC−30–120 °C±0.1 °CDelta OHM, Parma, Italy
Global Radiation (G)Delta OHM HD2102.20.01 W/m2–199.99 × 103 W/m2±5% W/m2Delta OHM, Parma, Italy
Table 2. Respondents’ attributes.
Table 2. Respondents’ attributes.
SexNumberAge (Years)Height (m)Weight (kg)BMI (kg/m2)
Male5219.351.7570.8023.12
Female9719.481.6352.6119.75
Male + female14919.441.6758.9620.92
range 17–221.55–1.8547.1–86.119.11–31.07
Body Mass Index (BMI) = Mass/Height2 (kg/m2)
Table 3. Statistical results on mean values of climatic parameters for outdoor training.
Table 3. Statistical results on mean values of climatic parameters for outdoor training.
ParametersPRTAFTSTTARMDP
Ta (°C)29.8727.2727.6628.7528.71
Tg (°C)33.8832.7133.7132.8637.30
RH (%)61.8247.5565.0168.4059.27
Va (m/s)0.501.350.580.541.44
Iclo (clo)0.650.650.650.650.65
Tmrt (°C)34.5734.6932.6033.3940.26
G (W/m2)214.28443.59239.57261.27633.87
UTCI (°C)30.8227.4429.6031.3130.42
PET (°C)31.9928.1129.9130.9830.30
Table 4. Thermal sensation.
Table 4. Thermal sensation.
TaRHVaTgTmrtG
PRTA0.375 **−0.410 **0.1230.219 **0.191 *0.255 **
FT0.272 **−0.467 **0.0450.593 **0.581 **0.590 **
STTA0.499 **−0.246 **0.225 **0.548 **0.548 **0.557 **
RM0.649 **−0.421 **0.0900.546 **0.580 **0.577 **
DP0.291 **−0.300 **0.0140.348 **0.276 **0.349 **
** Significance at the 0.01 level; * significance at the 0.05 level.
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Zhang, H.; You, L.; Chen, B.; Wang, Y.; Guo, F.; Zhu, P. A Study on Outdoor Thermal Comfort During Military Training for College Freshmen: A Survey in a Cold Region of China. Buildings 2025, 15, 2454. https://doi.org/10.3390/buildings15142454

AMA Style

Zhang H, You L, Chen B, Wang Y, Guo F, Zhu P. A Study on Outdoor Thermal Comfort During Military Training for College Freshmen: A Survey in a Cold Region of China. Buildings. 2025; 15(14):2454. https://doi.org/10.3390/buildings15142454

Chicago/Turabian Style

Zhang, Hongchi, Liangshan You, Bingru Chen, Yuqiu Wang, Fei Guo, and Peisheng Zhu. 2025. "A Study on Outdoor Thermal Comfort During Military Training for College Freshmen: A Survey in a Cold Region of China" Buildings 15, no. 14: 2454. https://doi.org/10.3390/buildings15142454

APA Style

Zhang, H., You, L., Chen, B., Wang, Y., Guo, F., & Zhu, P. (2025). A Study on Outdoor Thermal Comfort During Military Training for College Freshmen: A Survey in a Cold Region of China. Buildings, 15(14), 2454. https://doi.org/10.3390/buildings15142454

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