Salt intake affects hydration levels because excessive sodium consumption can lead to increased thirst and fluid retention. High salt levels can disrupt the body's fluid balance, causing dehydration symptoms when not compensated with adequate water intake. On the other hand, some sodium is essential for electrolyte balance and optimal hydration, especially during intense exercise. Maintaining a moderate salt intake supports proper cellular function while ensuring the body efficiently manages hydration, especially in high-temperature or strenuous conditions.