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Journal of the American Podiatric Medical Association is published by MDPI from Volume 116 Issue 1 (2026). Previous articles were published by another publisher in Open Access under a CC-BY (or CC-BY-NC-ND) licence, and they are hosted by MDPI on mdpi.com as a courtesy and upon agreement with American Podiatric Medical Association.
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Article

Perceived Stress and Coffee and Energy Drink Consumption Predict Poor Sleep Quality in Podiatric Medical Students. A Cross-sectional Study

by
Mohomad Al Sawah
1,
Naeemah Ruffin
1,
Mohammad Rimawi
1,
Carmen Concerto
2,
Eugenio Aguglia
3,
Eileen Chusid
1,
Carmenrita Infortuna
1 and
Fortunato Battaglia
2,*
1
Department of Pre-clinical Sciences, New York College of Podiatric Medicine, New York, NY
2
Department of Health and Medical Sciences, Seton Hall University, South Orange, NJ
3
Department of Clinical and Molecular Biomedicine, Psychiatry Unit, University of Catania, Catania, Italy
*
Author to whom correspondence should be addressed.
J. Am. Podiatr. Med. Assoc. 2015, 105(5), 429-434; https://doi.org/10.7547/14-082
Published: 1 September 2015
Versions Notes

Abstract

Background: A cross-sectional survey administered to first- and second-year podiatric medical students aimed to investigate the effect of coffee intake, energy drink consumption, and perceived stress on sleep quality in medical students during their preclinical studies. Methods: Ninety-eight of 183 students contacted (53.6%) completed a questionnaire comprising standard instruments measuring sleep quality (Pittsburgh Sleep Quality Index), daytime sleepiness (Epworth Sleepiness scale), and perceived stress (ten-item Perceived Stress Scale). Furthermore, we investigated coffee and energy drink consumption. Logistic regression was conducted to identify factors associated with poor sleep quality and the relation between sleep quality and academic performance (grade point average). Results: High prevalences of poor sleep quality, excessive daytime sleepiness, and perceived stress were reported. In addition, higher odds of developing poor sleep quality were associated with coffee and energy drink intake, perceived stress, and excessive daytime sleepiness. The total Pittsburgh Sleep Quality Index score was inversely correlated with grade point average. Conclusions: First- and second-year podiatric medical students have poor sleep quality. Further research is needed to identify effective strategies to reduce stress and decrease coffee and energy drink intake to minimize their negative effect on sleep quality and academic performance in podiatric medical students.

A growing body of literature in recent years describes the role of sleep in normal brain functions and the risks of sleep deprivation for physical and mental health. Given the role of sleep in encoding and memory consolidation, attention, reasoning, and executive functions [1,2,3], it is likely that poor sleep quality might affect medical student academic performance [4]. During the first- and second-year courses of podiatric medical education, the scientific basis of health and diseases are taught in numerous courses. Students are expected to learn and retain large amounts of information, adhere to tough schedules, and take multiple examinations. It is, thus, very difficult to balance a healthy lifestyle while pursuing podiatric medical education. Previous studies strongly suggest that college students have high prevalences of sleep deprivation, poor sleep quality, and excessive daytime sleepiness (EDS) [5,6]. It is likely that this abnormal sleep pattern might have a negative effect on mood [7,8], academic performance [9,10], and addictive behaviors [11]. In addition, medical students– exposure to high stress levels [12,13,14] might aggravate sleep disturbances [15,16]. The interplay between stress and sleep is supported by a large body of literature [17]. Several brain areas and circuits are modulated by acute and chronic stressors. The stress-related neurochemical imbalance and abnormal synaptic plasticity [18,19] may, ultimately, determine the alterations in sleep.
College students consume a large amount of coffee and energy drinks (EDs) for studying, for wakefulness, to overcome fatigue, and to enhance cognitive performance [20,21]. Caffeine consistently activates the hypothalamo-pituitary-adrenal axis [22] and increases plasma cortisol levels [23]. Thus, caffeine intake and stress may contribute to poor sleep quality in college students.
To further characterize sleep quality in medical education and the effect of perceived stress and coffee and ED consumption, we investigated sleep quality in podiatric medical students in their preclinical years to identify behavioral characteristics that increase the odds of poor sleep in this student population.

Methods

This cross-sectional study was performed at New York College of Podiatric Medicine (New York, New York). First- and second-year podiatric medical students were surveyed during the 2013 academic year (April). All of the students were informed about the study via e-mail, and those who consented were enrolled in the study. After lectures, a questionnaire was provided to the students. Participation was voluntary, and responses were anonymous. To ensure confidentiality, after completing the questionnaire, the students were invited to seal it in an envelope and drop it in an empty box. The study was approved by the institutional review board of the New York College of Podiatric Medicine.

Survey Instruments

We collected self-reported information on students’ demographic features and coffee and ED consumption (coffee, ≥ 1 cup per day; EDs, ≥ 1 can per week). Academic performance was based on self-reported grade point average.
The Epworth Sleepiness Scale is an eight-item questionnaire designed to identify persons with EDS. Each item addresses, on a scale ranging from 0 to 3, the possibility of falling asleep in daily living. A total score of 10 or higher indicates EDS [24]. The scale has high internal consistency and reliability [25].
The Pittsburgh Sleep Quality Index (PSQI) [26] was used to assess sleep quality. The PSQI is a 19-item self-reported questionnaire that has open-ended questions and multiple-choice questions with answers about sleep-related variables during the preceding month. The PSQI investigates seven sleep components. Each sleep component is scored ranging from 0 to 3, with 3 indicating the greatest dysfunction. A total score of 5 or higher indicates poor sleep quality [26]. The PSQI has high internal consistency and reliability [27].
The ten-item Perceived Stress Scale (PSS-10) inquires about feelings and thoughts that are perceived as unpredictable and stressful. The PSS-10 uses a 5-point Likert scale: 0 = never, 1 = almost never, 2 = sometimes, 3 = fairly often, and 4 = very often. A higher score indicates greater perceived stress. This instrument has adequate internal and test-retest reliability [28,29].

Statistical Analysis

Sociodemographic characteristics, coffee and ED intake, perceived stress, sleep quality, and EDS were summarized using descriptive statistics. Factorial analysis of variance and the 𝒳2 test were used to compare sleep quality, EDS, and perceived stress scales with age, sex, academic year, and marital status. A logistic regression analysis was conducted to determine the impact of the variables on sleep quality. The collected data were statistically analyzed using a software program (IBM SPSS Statistics for Windows, Version 19.0; IBM Corp, Armonk, New York). A p < 0.05 was taken as the level of significance.

Results

Of 183 students contacted, 98 (53.6%) agreed to participate and completed the survey. The mean ± SD age of the respondents was 24.9 ± 2.9 years, 41 (41.8%) were women, 20 (20.4%) were married, and their mean ± SD grade point average was 3.0 ± 0.4. Sixty-nine of the respondents (70.4%) were first-year podiatric medical students (Table 1), 79 (80.6%) were coffee drinkers, and 48 (49.0%) regularly consumed EDs.
Table 1. Demographic Characteristics of the 98 Study Participants.
Table 1. Demographic Characteristics of the 98 Study Participants.
Japma 105 00429 i001
Sixty-seven students (68.4%) showed poor sleep quality (mean ± SE PSQI score, 7.3 ± 5.9), with a mean ± SE sleep duration of 5.9 ± 1.1 hours per night and median ± SE sleep latency of 24.33 ± 16.5 minutes. In addition, 44 students (44.9%) had EDS (mean ± SE Epworth Sleepiness Scale score: 8.6 ± 4.7) (Table 2). The overall mean ± SE PSS-10 score was 21.3 ± 5.9. Furthermore, the PSQI total score was inversely correlated with grade point average (p = 0.004).
Table 2. Sleep Quality and Its Component Scores.
Table 2. Sleep Quality and Its Component Scores.
Japma 105 00429 i002
There were no age, sex, or marital status differences in mean PSQI, Epworth Sleepiness Scale, and PSS-10 scores (p > 0.05) (Table 3). First-year students demonstrated a higher prevalence of poor sleep quality and higher stress levels (p < 0.05) (Table 3).
Table 3. Demographic Differences in Poor Sleep Quality, Excessive Daytime Sleepiness, and Perceived Stress
Table 3. Demographic Differences in Poor Sleep Quality, Excessive Daytime Sleepiness, and Perceived Stress
Japma 105 00429 i003
Logistic regression analysis was performed to identify the risk factors associated with poor sleep quality. Results are reported in Table 4. No relation was observed between female sex, age, academic year, grade point average, and marital status and the odds of developing poor sleep quality. Conversely, drinking a cup of coffee per day (adjusted odds ratio (AOR), 0.4; 95% confidence interval [CI], 0.2–0.9) and at least 1 can of ED per week (AOR, 3.8; 95% CI, 1–14.1) were associated with poor sleep quality. Furthermore, higher Epworth Sleepiness Scale (AOR, 6.4; 95% CI, 1.3–30.6) and PSS-10 (AOR, 1.2; 95% CI, 1.1–1.4) scores strongly increased the odds of poor sleep in podiatric medical students.
Table 4. Predictors of Poor Sleep Quality.
Table 4. Predictors of Poor Sleep Quality.
Japma 105 00429 i004

Discussion

This is the first study investigating sleep quality in podiatric medical students. The results showed a high prevalence of poor sleep quality, daytime sleepiness, and perceived stress. Coffee and ED intake and stress increased the odds of poor sleep quality.
A total of 68.3% of podiatric medical students showed poor sleep quality. This is a relatively high percentage compared with results from other sleep studies in college students {30,31] and might be because the study was performed in April, just a few weeks before final examinations. This is further supported by the high stress perceived by the students. A high percentage of podiatric medical students consumed coffee and EDs. This habit has a negative effect on sleep in college students [32] and leads to growing concern about student health hazards, particularly cardiovascular and neurologic toxic effects [33,34,35]. Energy drinks contain 80 to 140 mg of caffeine. Besides caffeine, ED formulations include ingredients such as ginseng, taurine, guarana, carbohydrates, panthenol, glucuronolactone, multivitamins, inositol, and niacin. These molecules still have largely unknown effects on brain function and may have synergistic pharmacologic effects beyond those of caffeine alone. Coffee consumption and ED intake improve psychomotor performance [36,37,38,39]; at the same time, they have a detrimental effect on sleep and [40,41,42] daytime functioning [43], and they increase depression and anxiety in college students [39,44] Caffeine also elevates glucocorticoid, catecholamine, and adrenocorticotropin levels and cortisol secretion, contributing to abnormal stress responses [45,46]. Thus, there is a large body of literature that supports the present results and the link between coffee and ED consumption and stress and sleep abnormalities.
Daytime sleepiness is highly prevalent in podiatric medical students. The data indicate a higher prevalence compared with the general population [47] and similar EDS compared with other medical students [48].
An important finding of this study is the relationship between sleep quality and grade point average. The link between sleep quality and academic performance is as yet insufficiently addressed in medical students [49,50,51]. As previously reported, this link might be stronger in students carrying an intense course load and examination schedule [52], as in the cohort we studied.
This study has some limitations. This is a single-institution study performed in a specific student population (podiatric medicine). However, owing to the similarity in the preclinical curriculum, we believe that these findings could be generalized to other medical student populations. In addition, we focused on specific behavioral habits (coffee and ED intake) often used by students during high academic demand. It cannot be excluded that other caffeinated drinks (soda and tea) might significantly contribute to poor sleep quality in podiatric medical students.

Conclusions

The present findings suggest that behavioral intervention aimed at managing stress and decreasing coffee and ED intake might reduce the occurrence of disturbed sleep in podiatric medical students.

Financial Disclosure

None reported.

Conflicts of Interest

None reported.

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MDPI and ACS Style

Al Sawah, M.; Ruffin, N.; Rimawi, M.; Concerto, C.; Aguglia, E.; Chusid, E.; Infortuna, C.; Battaglia, F. Perceived Stress and Coffee and Energy Drink Consumption Predict Poor Sleep Quality in Podiatric Medical Students. A Cross-sectional Study. J. Am. Podiatr. Med. Assoc. 2015, 105, 429-434. https://doi.org/10.7547/14-082

AMA Style

Al Sawah M, Ruffin N, Rimawi M, Concerto C, Aguglia E, Chusid E, Infortuna C, Battaglia F. Perceived Stress and Coffee and Energy Drink Consumption Predict Poor Sleep Quality in Podiatric Medical Students. A Cross-sectional Study. Journal of the American Podiatric Medical Association. 2015; 105(5):429-434. https://doi.org/10.7547/14-082

Chicago/Turabian Style

Al Sawah, Mohomad, Naeemah Ruffin, Mohammad Rimawi, Carmen Concerto, Eugenio Aguglia, Eileen Chusid, Carmenrita Infortuna, and Fortunato Battaglia. 2015. "Perceived Stress and Coffee and Energy Drink Consumption Predict Poor Sleep Quality in Podiatric Medical Students. A Cross-sectional Study" Journal of the American Podiatric Medical Association 105, no. 5: 429-434. https://doi.org/10.7547/14-082

APA Style

Al Sawah, M., Ruffin, N., Rimawi, M., Concerto, C., Aguglia, E., Chusid, E., Infortuna, C., & Battaglia, F. (2015). Perceived Stress and Coffee and Energy Drink Consumption Predict Poor Sleep Quality in Podiatric Medical Students. A Cross-sectional Study. Journal of the American Podiatric Medical Association, 105(5), 429-434. https://doi.org/10.7547/14-082

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