Search Results (11)

Plastic pollution has emerged as one of the most pervasive environmental challenges, with microplastics (MPs) widely distributed across marine ecosystems worldwide. This study aimed to assess the uptake of MPs by key fish and invertebrate species from different locations in the coastal zone of the Bulgarian Black Sea. Fish were collected during routine monitoring surveys in September–November 2024, while invertebrates were obtained via scuba diving. The presence of MPs in fish stomachs and invertebrate soft tissues, and their polymer composition, shape and size were analyzed using an Agilent 8700 LDIR Chemical Imaging System. Potential biological effects of ingested MPs were evaluated by an integrated Specific Oxidative Stress (SOS) index. The results revealed MP uptake levels comparable to those reported globally. Small-sized particles (<50 µm) with rounded shapes were most abundant across studied taxa. Polymer composition varied considerably depending on species and sampling region, indicating differences in exposure sources and environmental conditions. Oxidative stress levels in both fish and invertebrates showed substantial interspecific variation, and clear differences between the northern and southern region of the Bulgarian Black Sea. Overall, elevated uptake of MPs appears to contribute to oxidative stress in marine organisms, potentially affecting their health status, resilience, and adaptive capacity, as reflected by increased SOS index values. Full article

Monitoring heart rate (HR) and peripheral oxygen saturation (SpO₂) in underwater environments has gained increasing importance due to the expanding popularity of diving activities such as SCUBA diving, freediving, and professional underwater operations. These physiological parameters are critical indicators for detecting adaptive responses and early signs of physiological distress caused by environmental stressors like elevated ambient pressure, hypoxia, cold temperatures, and psychological stress. Although recent advances in wearable sensor technologies offer new opportunities for real-time physiological monitoring underwater, significant limitations persist due to issues such as signal interference, cold-induced vasoconstriction, sensor durability, and the complexity of reliably measuring these parameters in dynamic underwater conditions. Evidence shows HR can fall by more than 50% in freedivers and SpO₂ may decline to below 50% during repeated dives, with proposed depth-specific thresholds (e.g., <98.5% at 30 m) serving as early warning levels. This review synthesizes current knowledge on the cardiovascular and oxygenation responses observed during diving, explores the technological challenges associated with underwater HR and SpO₂ monitoring, and discusses future directions, including the integration of multisensor platforms and predictive analytics to enhance diver safety and physiological monitoring capabilities. Addressing these technological and methodological gaps holds the potential to substantially improve safety standards and expand the clinical applicability of underwater physiological monitoring systems. Full article

Human engagement in extreme activities, from spaceflight to deep-sea diving and extreme sports, presents unique physiological challenges. Understanding the molecular mechanisms underlying adaptations to these demands is crucial for developing strategies to enhance human performance and resilience in such environments. This review integrates multi-omics data across a range of extreme phenotypes, including astronauts, scuba divers, acute alcohol consumers, long-haul flight passengers, bodybuilders, and simulation racers. We analyze current literature in genomic, transcriptomic, proteomic, metabolomic, and metagenomic studies to identify common and phenotype-specific adaptations, highlighting potential biomarkers and pathways associated with resilience in harsh conditions. This integrated approach offers insights into human adaptability and provides a foundation for developing personalized strategies to mitigate risks and enhance performance in extreme environments, with particular relevance to extended spaceflight. Full article

This review examines the relationship between the physiological demands of diving and premature ventricular complexes (PVCs) in divers. In the general population, some individuals have a greater tendency to experience PVCs, often without awareness or a clear understanding of the triggering factors. With the increasing availability and popularity of both scuba and apnoea diving, more people, including those with a predisposition to PVCs, are engaging in these activities. The underwater environment, with its unique stressors, may increase the risk of arrhythmogenic events, particularly PVCs. Here, we review the prevalence, pathophysiology, and aggravating factors of PVCs in divers, emphasising the need for a comprehensive cardiovascular assessment. Evidence suggests a higher prevalence of PVCs in divers compared with the general population, influenced by factors such as age, dive depth, gas bubbles, cold water immersion, pre-existing cardiovascular diseases, and lifestyle factors. The change in environment during diving could potentially trigger an increased frequency of PVCs, especially in individuals with a pre-existing tendency. We discuss diagnostic strategies, management approaches, and preventive measures for divers with PVCs, noting that although guidelines for athletes can be adapted, individual assessment is crucial. Significant knowledge gaps are identified, highlighting the need for future research to develop evidence-based guidelines and understand the long-term significance of PVCs in divers. This work aims to evaluate potential contributing factors to PVCs in divers and identify individuals who may be at higher risk of experiencing major adverse cardiovascular events (MACEs). This work aims to improve diver safety by promoting collaboration between cardiologists and diving medicine specialists and by identifying key areas for future investigation in this field. This work aims to improve the safety and well-being of divers by understanding the cardiovascular challenges they face, including pressure changes, cold water immersion, and hypoxia. We seek to elucidate the relationship between these challenges and the occurrence of PVCs. By synthesising current evidence, identifying knowledge gaps, and proposing preliminary recommendations, we aim to encourage collaboration between cardiologists and diving medicine specialists to optimise the screening, management, and risk stratification of PVCs in the diving population. Full article

The present study investigated the influence of SCUBA dives with compressed air at depths of 10 and 20 m on ECG-derived HRV parameters in apparently healthy individuals. We hypothesized that cardiac sympathetic activity (measured by HRV parameters) adapts proportionally to diving depth, and that both time- and frequency-domain parameters are sensitive enough to track changes in cardiac ANS function during diving activities and subsequently during the recovery period. Eleven healthy middle-aged recreational divers (nine men and two women, age 43 ± 8, all nonsmokers) volunteered to participate in the present study. The participants (all open-circuit divers) were equipped with dry suits and ECG Holter devices and were later randomly assigned to dive pairs and depths (10 m vs. 20 m), and each participant served as his or her own control. No interaction effects (diving depth x time epoch) were found for the most commonly used HRV markers. More precisely, in response to two different diving protocols, a significant post hoc effect of time was observed for HR and SDNN, as these parameters transiently decreased during the dives and returned to baseline after ascent (p < 0.001). The ULF, VLF (p < 0.003), TP, and LF parameters decreased significantly during the dives, while HF significantly increased (p < 0.003). SCUBA diving apparently challenges the cardiac ANS, even in healthy individuals. The observed changes reveal possible underwater methods of influencing the parasympathetic activity of the heart depending on the depth of the dive. These results identify autonomic nervous system markers to track the cardiovascular risk related to diving and point to the possibility of tracking cardiovascular system benefits during underwater activities in selected patients. Full article

Underwater activities are characterized by an imbalance between reactive oxygen/nitrogen species (RONS) and antioxidant mechanisms, which can be associated with an inflammatory response, depending on O₂ availability. This review explores the oxidative stress mechanisms and related inflammation status (Oxy-Inflammation) in underwater activities such as breath-hold (BH) diving, Self-Contained Underwater Breathing Apparatus (SCUBA) and Closed-Circuit Rebreather (CCR) diving, and saturation diving. Divers are exposed to hypoxic and hyperoxic conditions, amplified by environmental conditions, hyperbaric pressure, cold water, different types of breathing gases, and air/non-air mixtures. The “diving response”, including physiological adaptation, cardiovascular stress, increased arterial blood pressure, peripheral vasoconstriction, altered blood gas values, and risk of bubble formation during decompression, are reported. Full article

There are a considerable number of studies reporting the negative impacts of recreational diving and their causes, yet there is a gap in the information regarding the aspects of activity management. This paper presents a systematic approach to the management measures found in the literature. A large part of the measures identified address stakeholders’ awareness, data on the activity, and implementing adapted management measures. Stakeholders need to be integrated into the entire process of managing the activity because they are the target for correcting actions. A knowledge gap of the evaluation of the “ecological carrying capacity” of dive sites exists, along with a lack of methods for its assessment. This study informs future steps on the development of an integrated management and monitoring model that encompasses the assessment of ecological carrying capacity in further research. It also brings a vision of sustainable management of the recreational diving activity by advancing the conceptual framework of scuba diving and tourism integrated management. Full article

The impacts of scuba diving on people with physical impairments are unknown. Grounded on the social identity approach to health, the aim of this study was to test and describe the relationships between scuba diving social identity, self-efficacy, social health, psychological health, physical health, health-related quality of life (HRQOL), and disability level among recreational scuba divers with physical impairments. A mixed methods explanatory sequential design was employed. The quantitative strand used an 80-item cross-sectional survey, with the data analyzed via a path analysis. The qualitative strand used 1:1 interviews across 3 case study groups; the data were analyzed using deductive and inductive analyses. Mixing occurred via a joint display with meta-inferences. The quantitative results (n = 78) indicated that self-efficacy was a significant predictor of social health, psychological health, physical health, HRQOL, and disability level. The qualitative findings (n = 15) consisted of six themes, whereby participants described scuba as a positive social identity that provides them with meaning, purpose, and belonging. Furthermore, they described scuba diving as a positive contributor to their self-efficacy, social health, psychological health, physical health, and quality of life. During the mixing of data, the quantitative and qualitative results did not match on the influence of scuba diving social identity on self-efficacy, social health, psychological health, physical health, HRQOL, and disability level. A further analysis revealed that the range restriction impaired the conclusive quantitative evidence on the scuba diving social identity variable. The meta-inferences derived from the data integration suggest that scuba diving plays a role in the self-efficacy, health, HRQOL, and disability level among scuba divers with physical impairments. The findings point to the potential of scuba diving as a health promotion recreational activity and rehabilitation modality for people with physical impairments. Full article

In recent studies, oxidative stress after scuba diving has been explored by measuring urinary biomarkers in volunteers under controlled conditions. Dive depth and duration, water temperature, and workload are all variables that can elicit metabolic responses. A controlled diving experiment was performed in an indoor pool at 20, 30, and 40 m depths at a water temperature of 32 °C, on three different days. Samples of urine from five male scuba divers were taken before diving and at four time points after diving, and then tested for their concentration of five different oxidative stress biomarkers by means of liquid chromatography tandem mass spectrometry and by ¹H nuclear magnetic resonance metabolomics analysis. The results showed no variation in the five biomarkers after diving, but a decreasing trend was observed over the three days, with no differences among the three depths. The lack of effect on oxidative stress biomarkers has been attributed to the comfortable water temperature and to the absence of exercise in the divers during the experiment. Instead, an increase in hypoxanthine excretion, which can be considered a biomarker sensitive to hyperbaric exposure, was found after diving. Finally, the results suggest a physiological mechanism of metabolic adaptation to a new condition. Full article

Environmental Physiology at Boise State University, Idaho, is a multidisciplinary course that expands students’ understanding of human regulatory physiology through acute and chronic responses to environmental extremes. Students explore the physics (pressure, fluid dynamics, gas laws, sound, and light) of the underwater environment, marine flora and fauna adaptations to this environment, and the human experience within this environment. Included is completion of the Professional Association of Dive Instructors (PADI) Open Water Scuba Certification. The course culminates in an international dive trip where course concepts are further demonstrated and explored, and conservation activities are undertaken. Full article

Since ancient times humans observed animal and plants features and tried to adapt them according to their own needs. Biomimetics represents the foundation of many inventions from various fields: From transportation devices (helicopter, airplane, submarine) and flying techniques, to sports’ wear industry (swimming suits, scuba diving gear, Velcro closure system), bullet proof vests made from Kevlar etc. It is true that nature provides numerous noteworthy models (shark skin, spider web, lotus leaves), referring both to the plant and animal kingdom. This review paper summarizes a few of “nature’s interventions” in human evolution, regarding understanding of surface wettability and development of innovative special surfaces. Empirical models are described in order to reveal the science behind special wettable surfaces (superhydrophobic /superhydrophilic). Materials and methods used in order to artificially obtain special wettable surfaces are described in correlation with plants’ and animals’ unique features. Emphasis is placed on joining superhydrophobic and superhydrophilic surfaces, with important applications in cell culturing, microorganism isolation/separation and molecule screening techniques. Bio-inspired wettability is presented as a constitutive part of traditional devices/systems, intended to improve their characteristics and extend performances. Full article