What should be monitored closely to prevent heat injuries in individuals with pre-existing conditions?

Monitoring hydration levels is essential for preventing heat injuries, especially in individuals with pre-existing conditions such as cardiovascular issues, kidney problems, or those taking certain medications that affect fluid balance. Proper hydration helps regulate body temperature and allows the body to effectively cool itself through sweating. When hydration levels are low, the risk of heat exhaustion or heat stroke increases significantly, as the body's ability to dissipate heat becomes compromised.

While mental state, dietary preferences, and resting heart rate can be important indicators of overall health and performance, they do not directly address the critical need for adequate fluid intake in hot environments. Hydration affects physical performance, cognitive function, and physiological responses to heat stress, making it a top priority in heat injury prevention strategies.