Dehydration in Sports

The body uses the kidney, bladder, and thirst mechanisms in an intricate system to maintain the proper fluid levels in the body. When this system is stressed, such as during exercise, the system may not be able to maintain these levels. This results in the body lacking water (dehydration). Dehydration can be a problem because the body requires a certain amount of water and other fluids to maintain its blood volume. Fluid is lost when you urinate, sweat, breathe, vomit, or have diarrhea. Dehydration occurs when you drink less fluid than you lose. Dehydration may occur even before you become thirsty. It is important for athletes to keep drinking during activity, even if they do not feel thirsty.


  • Thirst.

  • Dry mouth.

  • Tiredness (lethargy).

  • Dark urine.

  • Headache.

  • Muscle cramps.

  • Rapid breathing.

  • Lightheadedness, especially when you stand from a sitting position.

  • Dry, warm skin.

  • Little or no urination.

  • Low blood pressure.

  • Fainting (syncope).

  • Delirium or unconsciousness.


  • Diarrhea.

  • Vomiting.

  • Inadequate fluid intake during an illness or strenuous exercise.

  • Inadequate food intake during an illness, during strenuous exercise, or after strenuous exercise.

  • Use of diuretic medicines, which control excess body fluid by causing fluid loss.

  • Certain age groups. Infants and the elderly are at greater risk.


  • Drink frequently throughout physical activity even if you do not feel thirsty. Drink small amounts of fluid frequently throughout and after sporting events.

  • Drink extra fluids to keep up with any ongoing losses (sweating, diarrhea).

  • Carry extra water and the ingredients for making an oral rehydration solution (ORS).

  • If you have diarrhea or vomiting or you are not drinking much, force yourself to drink more liquids before you become dehydrated.


  • Reduced ability to dissipate heat, resulting in elevated core body temperatures.

  • Heat illness.

  • Heat stroke.

  • Kidney failure.


Mild dehydration is treated by drinking enough fluid to replace the fluids you have lost. You may also need to replace the electrolytes you have lost. Recommendations for replenishing fluids and electrolytes include drinking sips of water slowly, eating foods with salt, drinking sports drinks, or taking over-the-counter dehydration medicines. Treat dehydration immediately. Do not wait until dehydration becomes severe.

Packets of ORS are widely available. Follow the directions on the packet. If no instructions are given, mix the contents of the ORS with 1 quart or liter of drinking water. If you are not sure if the water is safe to drink, first boil the water for at least 5 minutes.

If you are unable to obtain ORS you may create your own by adding 2 tbs of sugar or honey, ¼ tsp salt, and ¼ tsp baking soda to 1 quart or liter of water. If you do not have any baking soda, add another ¼ tsp of salt. If possible, add ½ cup orange juice or some mashed banana to improve the taste and provide some potassium.

Drink sips of the ORS every 5 minutes until urination becomes normal. It is normal to urinate 4 or 5 times a day. Adults and adolescents should drink at least 3 quarts or liters of ORS a day until they are well. For individuals who are vomiting or have diarrhea, it is important to keep trying to drink the ORS. Your body may retain some of the fluids and salts you need even if you are vomiting or have diarrhea. Remember to take only sips of liquids. Chilling the ORS may help.

Severe dehydration is a medical emergency. If you have symptoms of severe dehydration, seek medical care immediately. It may be necessary for you to receive intravenous (IV) fluids. If you are able to drink, you should also drink the ORS. With treatment for dehydration, whatever is causing diarrhea, vomiting, or other symptoms should also be treated.