Which condition results from a lack of adequate water intake during activity?

Insufficient water intake during physical activity leads to dehydration, which significantly impairs several bodily functions and performance. When hydration levels drop, the body's ability to regulate temperature diminishes, resulting in increased body temperature and fatigue. Additionally, dehydration can lead to reduced blood volume, making it harder for the heart to pump blood effectively, thereby decreasing the delivery of oxygen and nutrients to muscles. This means that without adequate water intake, an individual's overall performance can decline, manifesting in decreased endurance, strength, and coordination. Hence, the condition of decreased performance is directly associated with a lack of proper hydration during exercise.