Fluid balance

Research overview

At a glance

• The study of the effect of coffee, and caffeine, on fluid balance can be split into two distinct areas: caffeine intake during exercise and caffeine intake at rest in the general population. Recent research shows that:

Moderate caffeine consumption does not lead to dehydration in the general population.

During exercise, caffeine is beneficial for endurance performance and does not contribute to dehydration.

• Advice to abstain from drinking moderate amounts of caffeinated coffee, in order to maintain adequate fluid balance, is unfounded.

Moderate coffee consumption contributes to our fluid requirements and does not lead to dehydration, or significant loss of body fluid.

The mild, short-term diuretic effect of caffeine is not strong enough to counter-balance the benefits of fluid intake from coffee drinking. Black coffee contains more than 95% water.