Hydration is crucial for performance, especially in hot environments. When exercising in heat, the body loses fluids rapidly through perspiration, which can lead to dehydration and impaired physical performance. Maintaining hydration helps regulate body temperature and supports cardiovascular function, enhancing endurance and reducing fatigue. It's essential to prehydrate and hydrate during and after exercise, consuming electrolytes when necessary to replace lost salts. Balancing hydration is key to optimizing performance and avoiding heat-related illnesses.