Thermoregulation refers to the physiological processes by which the human body maintains its core temperature within a narrow range, typically around 37°C, despite variations in environmental conditions. Maintenance of body temperature is essential because enzymatic reactions, cellular metabolism, and organ functions are highly temperature dependent. Even slight deviations from normal body temperature can adversely affect physiological functions and may become life-threatening if not corrected.¹

The hypothalamus serves as the principal thermoregulatory center of the body. It receives input from central and peripheral thermoreceptors and coordinates responses that either conserve heat or promote heat loss. When body temperature rises, mechanisms such as vasodilation and sweating are activated to facilitate heat dissipation. Conversely, exposure to cold triggers vasoconstriction and shivering to conserve and generate heat.²

Sweat glands are specialized exocrine glands distributed throughout the skin. Humans possess approximately 2–4 million sweat glands, primarily of the eccrine type, which are responsible for thermoregulatory sweating. Eccrine glands are especially abundant on the palms, soles, forehead, and trunk. Apocrine glands, located mainly in the axillary and genital regions, contribute minimally to thermoregulation and are primarily involved in scent production.³

Sweating is considered the most effective mechanism for heat loss in humans, particularly in hot environments and during physical activity. The evaporation of sweat from the skin surface removes heat from the body and helps maintain thermal equilibrium. The process is controlled by the sympathetic nervous system through cholinergic nerve fibers that stimulate eccrine sweat glands.⁴

Several factors influence sweat production, including age, sex, physical fitness, hydration status, acclimatization to heat, emotional stress, and environmental temperature. Men generally exhibit higher sweat rates than women because of differences in body composition, hormonal influences, and sweat gland output. Furthermore, trained individuals demonstrate enhanced sweating efficiency and improved heat tolerance compared with sedentary individuals.⁵

Abnormalities in sweating can lead to significant clinical conditions. Excessive sweating (hyperhidrosis) may impair quality of life, while reduced sweating (hypohidrosis or anhidrosis) can increase susceptibility to heat-related illnesses. Heat exhaustion and heat stroke remain important public health concerns, especially in tropical climates and among individuals exposed to prolonged heat stress.⁶

Previous studies have investigated various aspects of thermoregulation and sweat gland function; however, there remains a need for observational studies evaluating physiological responses under controlled heat exposure. Understanding normal sweating responses provides valuable insight into mechanisms that maintain thermal homeostasis and can aid in identifying pathological deviations.

Therefore, the present study was conducted to assess thermoregulatory responses and sweat gland physiology among healthy adults exposed to controlled thermal stress conditions.

A cross-sectional observational study was conducted in the Department of Physiology over a period of three months. Study Population A total of 100 healthy adult volunteers between 18 and 40 years of age were recruited from students and staff members of the institution. Inclusion Criteria 1. Healthy adults aged 18–40 years. 2. Both male and female participants. 3. Individuals willing to provide informed consent. Exclusion Criteria 1. History of cardiovascular disease. 2. Endocrine disorders affecting thermoregulation. 3. Skin disorders involving sweat glands. 4. Current febrile illness. 5. Use of medications affecting sweating. Ethical Considerations The study protocol was approved by the Institutional Ethics Committee. Written informed consent was obtained from all participants before enrollment. Study Procedure Participants were instructed to avoid strenuous exercise, caffeine, and alcohol for 24 hours before testing. Baseline measurements were recorded in a climate-controlled laboratory maintained at 24°C. The following parameters were measured: • Body temperature (oral thermometer) • Heart rate • Blood pressure • Sweat rate Participants were then exposed to an environmental chamber maintained at 35°C with 50% relative humidity for 30 minutes. Sweat rate was estimated using pre- and post-exposure body weight measurements and standardized sweat collection methods. Body temperature and physiological parameters were recorded at baseline and immediately after heat exposure. Outcome Measures Primary Outcome • Change in sweat rate following heat exposure. Secondary Outcomes • Change in body temperature. • Change in heart rate. • Gender differences in sweating response. Statistical Analysis Data were entered into Microsoft Excel and analyzed using SPSS version 25. Continuous variables were expressed as mean ± standard deviation. Categorical variables were expressed as percentages. Comparisons between groups were performed using Student’s t-test. A p-value <0.05 was considered statistically significant.

Table 1. Demographic Characteristics of Participants (n=100)

The study included 100 healthy adults, with males representing 55% of participants. The average age was 26.8 years.

Table 2. Physiological Parameters Before and After Heat Exposure

Heat exposure resulted in significant increases in body temperature, heart rate, and sweat production. Sweat rate increased more than sixfold following thermal stress.

Table 3. Comparison of Sweat Rate Between Males and Females

Male participants exhibited higher sweat rates than female participants, suggesting sex-related differences in thermoregulatory responses.

The present study evaluated thermoregulatory responses and sweat gland activity among healthy adults exposed to controlled heat stress. The findings demonstrated significant increases in sweat production and physiological adaptations that facilitate heat dissipation. The hypothalamus plays a central role in maintaining body temperature by integrating thermal information from peripheral and central receptors. Increased body temperature activates heat-loss mechanisms, particularly sweating and cutaneous vasodilation. The observed rise in sweat production following heat exposure is consistent with established thermoregulatory physiology.² The average sweat rate increased markedly after heat exposure, highlighting the importance of eccrine sweat glands in evaporative cooling. Similar findings were reported by Shibasaki and Crandall, who demonstrated that sweat secretion increases proportionally with rising body temperature and environmental heat stress.⁷ The increase in heart rate observed during heat exposure reflects cardiovascular adjustments that facilitate heat dissipation. Enhanced skin blood flow allows transfer of core heat to the body surface, where it can be lost through radiation, convection, and evaporation.⁸ The present study also found higher sweat rates among male participants. Previous investigations have attributed sex differences in sweating to hormonal influences, body composition, and sweat gland output. Gagnon and Kenny reported that men generally produce greater sweat volumes than women under comparable thermal conditions.⁹ Efficient sweating is essential for preventing heat-related illnesses. Failure of thermoregulatory mechanisms may result in heat exhaustion or heat stroke, particularly during prolonged exposure to hot environments. Climate change and increasing global temperatures have heightened the importance of understanding human thermoregulation.¹⁰ The findings of this study support previous research indicating that sweating remains the primary avenue of heat dissipation in humans. The strong relationship between body temperature and sweat production demonstrates the adaptive capacity of the thermoregulatory system. A limitation of this study is the relatively short duration of heat exposure and the inclusion of only healthy adults. Future studies should evaluate thermoregulatory responses across different age groups, occupational settings, and disease conditions. Overall, the results contribute to the understanding of normal sweat gland physiology and highlight the importance of sweating in maintaining thermal homeostasis.

Sweat glands play a critical role in thermoregulation by facilitating evaporative heat loss. Heat exposure significantly increases sweat production, body temperature, and cardiovascular responses. Male participants demonstrated greater sweating capacity than females. Understanding thermoregulatory mechanisms is essential for preventing heat-related disorders and promoting human health under varying environmental conditions.

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