Sex differences in the physiological responses to exercise-induced dehydration: consequences and mechanisms
K A Wickham1, D G McCarthy2, L L Spriet3
1Environmental Ergonomics Lab, Brock University, St. Catharines, Ontario, Canada.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|July 1, 2021
Summary
Mild dehydration increases exercise strain, potentially affecting females more due to lower body water. This review explores sex differences in thermoregulation and cardiac strain during exercise dehydration.
Area of Science:
- Exercise Physiology
- Environmental Physiology
- Human Performance
Background:
- Mild dehydration (1%-3% body mass loss) elevates physiological strain during exercise.
- Existing research lacks direct comparative data on sex-dependent responses to exercise dehydration.
- Thermoregulatory and cardiac strain are key physiological responses to dehydration during physical activity.
Purpose of the Study:
- To explore the potential impact of sex on thermoregulatory and cardiac strain during exercise-induced dehydration.
- To develop a framework for future research investigating sex differences in exercise physiology.
- To synthesize existing data to compare male and female responses to dehydration during exercise.
Main Methods:
- Systematic review comparing trends from studies with similar protocols recruiting males and females separately.
- Analysis of core body temperature (Tc) and cardiac strain indicators.
- Exploration of physiological mechanisms underlying potential sex differences.
Main Results:
- Higher core body temperature (Tc) observed in both sexes with dehydration, seemingly at lower body mass loss percentages in females.
- Similar trends suggesting potentially higher cardiac strain in females, though less conclusive.
- Females may experience greater physiological strain from the same percentage of body mass loss due to lower relative body water volume.
Conclusions:
- Limited evidence suggests sex-based differences in thermoregulatory and cardiac strain during exercise dehydration.
- Females may experience earlier and greater thermoregulatory challenges due to faster Tc increases and potentially lower sweating rates.
- Further research is warranted to elucidate the precise mechanisms and extent of sex differences in response to exercise-induced dehydration.
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