Hydrating the Athlete

Hydration is key to optimal exercise performance.  Poor hydration in athletes leads to decreased blood volume.  Lower blood volume (thicker blood) causes the heart and the rest of the cardiovascular system to work harder and results in lower cardiac output.  Decreased blood volume also promotes rapid use of glycogen which makes us fatigue faster. It also causes a greater rise in body temperature putting athletes at risk for heat stroke.  Even a slight dehydration can affect athletic performance.  Signs of dehydration include excessive sweating, tiredness, cramping, loss of appetite, flushed skin, headache, dizziness, nausea, dark yellow urine, sticky feeling mouth.

Hydration recommendations:


2-3 hours before exercise: 16-20 oz fluid

During exercise

The goal is to replace same amount of fluids lost in sweat during exercise. Pre and post exercise weight can be obtained to figure this out.  Multiply pounds lost by 16 to obtain ounces lost.  This is the ideal number of ounces to drink during exercise.  Ideally, you would split this amount up every 15 minutes during exercise (usually between 5-10 oz every 15 minutes). If not, replace after.  Sports drinks are helpful because they replenish sodium and potassium lost in sweat.


16-20 oz of fluid for every pound lost.

Rest Days

Divide weight in pounds by 2.2 to get kilograms of bodyweight.  This is the # of ounces most people need to maintain normal hydration.

What counts as fluid? Water, flavored, waters, sports drinks, tea, coffee, fruit juice, smoothies, Jell-o, Soup, Fruits and Vegetables with a high water content.

It is possible to over-hydrate and cause water intoxication.  This can dilute the sodium levels in your body and is also called hyponatremia. To avoid over-hydration, don’t drink more than you sweat or lose in urine. Drinking sports drinks can decrease the likelihood of hyponatremia because they contain some sodium.

Read more about fueling the athlete: Micronutrient Concerns for Athletes and  Feeding the Athlete

Gina LileComment