Cardiovascular adaptations supporting human exercise-heat acclimation.

Area of Science:

• Physiology
• Environmental Health
• Exercise Science

Background:

• The cardiovascular system plays a critical role in exercise-heat acclimation, minimizing physiological strain and heat illness risk.
• Human physiology faces challenges in regulating circulation and blood pressure during exercise in heat, balancing muscle and skin blood flow.
• Recent research indicates temperature-sensitive mechanisms may influence skeletal muscle blood flow during heat stress, challenging traditional views.

Purpose of the Study:

• To review the cardiovascular adaptations and fluid volume adjustments during exercise-heat acclimation.
• To explore how these adaptations improve heat loss and exercise capacity.
• To examine the interplay between cardiovascular regulation, heat dissipation, and skeletal muscle perfusion.

Main Methods:

• This is a review article, synthesizing existing research on exercise-heat acclimation.
• It analyzes studies focusing on cardiovascular responses, total body water, and plasma volume changes.
• The review considers factors influencing the magnitude of these adaptations.

Main Results:

• Exercise-heat acclimation leads to increased total body water and plasma volume expansion.
• Adaptations include improved stroke volume, reduced heart rate, enhanced ventricular filling, and myocardial efficiency.
• Enhanced skin blood flow and sweating responses are key outcomes, alongside potential increases in skeletal muscle blood flow.

Conclusions:

• Cardiovascular adaptations are integral to successful exercise-heat acclimation, supporting both heat loss and sustained exercise.
• Fluid volume expansion and improved cardiac function are critical for managing exercise-heat stress.
• The extent of these adaptations varies based on exercise parameters and environmental conditions.