High skin temperature and hypohydration impair aerobic performance

Area of Science:

• Exercise Physiology
• Environmental Physiology
• Human Performance

Background:

• Submaximal aerobic exercise performance is sensitive to thermal stress.
• Both hot skin and hypohydration independently affect physiological responses during exercise.
• Understanding the interplay between skin temperature and hydration status is crucial for optimizing athletic performance.

Purpose of the Study:

• To review the roles of hot skin and hypohydration in impairing submaximal aerobic performance.
• To differentiate the independent and combined effects of hot skin and hypohydration on exercise capacity.
• To identify the primary thermal factor responsible for aerobic performance impairment.

Main Methods:

• Review of existing literature on exercise physiology and thermal stress.
• Analysis of studies investigating the effects of varying skin temperatures and hydration levels.
• Examination of physiological mechanisms, including skin blood flow and cardiac filling.

Main Results:

• Hot skin, characterized by high skin blood flow requirements, impairs aerobic performance even with modest core temperature elevation in euhydrated individuals.
• High core temperature alone (around 40°C) does not impair aerobic performance if skin temperature is cool-warm.
• Hypohydration exacerbates aerobic performance impairment, with significant decrements observed as skin temperature rises above 27°C.

Conclusions:

• Hot skin, rather than high core temperature, is the primary factor limiting submaximal aerobic performance in euhydrated states.
• Hypohydration significantly amplifies the negative impact of hot skin on aerobic exercise capacity.
• Maintaining optimal hydration and managing skin temperature are critical for sustaining aerobic performance under thermal stress.