Exercise-heat acclimation in young and older trained cyclists

Area of Science:

• Exercise Physiology
• Environmental Physiology
• Aging Research

Background:

• Heat acclimation improves physiological responses to exercise in hot environments.
• Understanding age-related differences in heat acclimation is crucial for optimizing training and safety.

Purpose of the Study:

• To investigate the influence of age on the capacity to acclimatize to exercise-heat stress.
• To test the hypothesis that age does not affect body temperature and heat loss responses during short-term exercise-heat acclimation in trained individuals.

Main Methods:

• Seven young (19-32 years) and seven older (50-63 years) highly trained subjects were studied.
• Subjects underwent exercise testing (60 min at 70%VO2max) in hot-dry and thermoneutral conditions before and after 6 days of exercise-heat acclimation.
• Measurements included rectal temperature, skin temperature, heart rate, cutaneous vascular conductance, and whole body sweat loss.

Main Results:

• Body temperature, skin temperature, heart rate, cutaneous vascular conductance, and sweat loss were similar between age groups pre- and post-acclimation.
• Both young and older groups showed similar relative decreases in rectal temperature and increases in sweat loss after heat acclimation.
• Younger subjects exhibited significant reductions in heart rate and increases in cutaneous vascular conductance post-acclimation, which were not observed in older subjects.

Conclusions:

• Age does not alter the capacity for acclimatization of body temperature or sweat loss to exercise-heat stress in highly trained adults.
• Cardiovascular adaptations to short-term exercise-heat acclimation differ between young and older trained individuals.
• These findings suggest that while cardiovascular responses vary, the fundamental physiological adjustments for heat tolerance are preserved with age in trained populations.