Did you know the human body is made up of 40–75% water? Muscle tissue alone contains 70–75% water, which makes hydration essential for both health and performance.

Water supports nearly every system in the body. It plays a role in:

Regulating body temperature

Transporting nutrients through the bloodstream

Providing structure to cells and tissues

Supporting cardiovascular and kidney function

Lubricating joints

Hydrating the skin

Cushioning the brain and spinal cord

Aiding digestion

Supporting physical performance during exercise

What Happens When You’re Dehydrated?

Dehydration occurs when fluid intake doesn’t match fluid loss. This can happen if you don’t drink enough water or if you lose excessive fluids through sweating, vomiting, or illness.

Even a 2% loss of body weight from fluid loss can begin to affect the body. Common signs and symptoms of dehydration include:

Dizziness

Increased thirst

Dark-colored urine

Fatigue

Headaches

Dry or sticky mouth

Confusion

Muscle cramps

Constipation

Low blood pressure

Electrolyte imbalances

Dehydration impacts more than just how you feel—it directly affects both physical and cognitive performance.

Effects of Dehydration on Performance

Physical performance effects:

Decreased strength

Decreased power

Reduced endurance

Cognitive effects:

Slower reaction time

Decreased coordination

Increased difficulty focusing

How Much Water Do You Need for Exercise?

The American College of Sports Medicine provides general guidelines for fluid intake around exercise:

Before exercise: Drink 14–22 oz of fluid about 2 hours before activity

During exercise: Consume 6–12 oz of water or a sports drink every 15–20 minutes

After exercise: Drink 16–24 oz of fluid for every pound of body weight lost during exercise

Sports drinks work best for workouts lasting longer than one hour or when exercising in hot conditions. For shorter or lower-intensity sessions, water typically meets hydration needs.

Staying hydrated supports performance, recovery, and overall health. Making water intake a consistent habit can have a meaningful impact on how your body feels and functions every day.

Sources:

-Riebl SK, Davy BM. The Hydration Equation: Update on Water Balance and Cognitive Performance. ACSMs Health Fit J. 2013;17(6):21-28. doi:10.1249/FIT.0b013e3182a9570f

-Penney, S. (no date) Recommended daily water intake for health and performance, NASM. Available at: https://blog.nasm.org/nutrition/hydration-health-performance (Accessed: 28 June 2024).