Human ACE I/D polymorphism is associated with individual differences in exercise heat tolerance.

Area of Science:

• Human Physiology
• Genetics
• Environmental Medicine

Background:

• The angiotensin I-converting enzyme (ACE) gene polymorphism, specifically the insertion (I)/deletion (D) variant, is linked to various physiological responses.
• Understanding genetic influences on thermoregulation is crucial for predicting human performance and health in heat stress environments.

Purpose of the Study:

• To investigate the association between the ACE (I/D) polymorphism and exercise heat tolerance in Caucasian men.
• To determine if ACE genotype influences physiological responses during heat exposure.

Main Methods:

• Fifty-eight Caucasian men underwent a 2-hour exercise heat-tolerance test.
• Genotyping for the ACE (I/D) polymorphism was performed.
• Physiological parameters including body core temperature, heat storage, and heart rate were measured and compared between ACE DD and I+ genotype groups.

Main Results:

• The ACE I+ genotype group showed significantly lower relative changes in body core temperature and heat storage compared to the DD genotype group during heat stress.
• Heart rate changes were also lower in the I+ group, though not statistically significant (P = 0.06).
• No significant associations were found between heat strain response and anthropometrical measurements or aerobic fitness.

Conclusions:

• The ACE I+ polymorphism is associated with enhanced exercise heat tolerance.
• ACE genotype may serve as a potential biomarker for predicting individual heat tolerance.
• Further research is warranted to elucidate the mechanisms underlying this association.