What physiological change is caused by exercising in heat?

Exercising in heat leads to several physiological adaptations to help maintain homeostasis and optimize performance. One key change is the increased heart rate. As the body temperature rises, blood flow is redirected to the skin to facilitate heat loss through sweating and evaporation. This diversion of blood flow can lead to a decrease in arterial blood pressure, prompting an increase in heart rate to ensure adequate circulation and oxygen transport to working muscles and vital organs.

Additionally, the heart rate increases as a response to the cardiovascular demands of exercise, particularly in hot conditions where thermoregulation is crucial. This heightened heart rate is important for maintaining performance and meeting metabolic demands during exercise in a heated environment.

The other options do not accurately reflect the physiological responses to exercising in heat. For instance, exercising in heat typically prompts increased blood flow to the skin rather than a decrease, and respiratory rates tend to increase, not decrease, as the body attempts to manage temperature and maintain adequate oxygen levels. VO2 max, which is an indicator of maximal oxygen uptake, may not necessarily increase due to heat exposure; instead, it can be affected more by factors like training adaptations over time rather than acute thermal stress.