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Whether you’re a serious athlete or a recreational exerciser, it’s important to make sure you get the right amount of water before, during, and after exercise. Water regulates your body temperature and lubricates your joints. It also helps transport nutrients to give you energy and keep you healthy. If you’re not properly hydrated, your body can’t perform at its highest level. You may experience fatigue, muscle cramps, dizziness, or more serious symptoms.

Path to improved health

A simple way to make sure you’re staying properly hydrated is to check your urine. If your urine is consistently colorless or light yellow, you are most likely staying well hydrated. Dark yellow or amber-colored urine is a sign of dehydration.

How much water should I drink while exercising?

There are no exact rules for how much water to drink while exercising because everyone is different. You need to consider factors including your sweat rate, the heat and humidity in your environment, and how long and hard you are exercising.

Dietitians of Canada has suggested the following basic guidelines for drinking water before, during, and after exercise:

• Drink 250 to 500 mL (1 to 2 cups) of fluid 4 hours before you start exercising
• Drink 125 to 375 mL (½ to 1½ cups) of fluid 2 hours or less before you start exercising if you have not urinated or only produced a small amount of dark yellow urine.
• Sip fluid during your activity. Avoid gaining weight, which can be a sign of overhydration. 
• If you drank regularly during your workout and there was no weight change, drink according to your thirst for the rest of the day. If you didn’t drink enough and lost weight, drink 500 to 750 mL (2 to 3 cups) of fluid per 0.5 kg (1 lb) of weight you lost.

What about sports drinks?

For most people, water is all that is needed to stay hydrated. However, if you will be exercising at a high intensity for longer than an hour, a sports drink may be helpful. The calories, potassium, and other nutrients in sports drinks can provide energy and electrolytes to help you perform for a longer period of time.

Choose a sports drink wisely. They are often high in calories from added sugar and may contain high levels of sodium.  Also, check the serving size. One bottle may contain several servings. If you drink the entire bottle, you may need to double or triple the amounts given on Nutrition Facts Label. Some sports drinks contain caffeine. If you use a sports drink that contains caffeine, be careful not to get too much caffeine in your diet. Caffeine may cause a diuretic effect on your body. This means that you may have to urinate more often.

Things to consider

Dehydration happens when you lose more fluid than you drink. When your body doesn’t have enough water, it can’t work properly. Dehydration can range from mild to severe. Symptoms of dehydration can include the following:

• Dizziness or lightheaded feeling
• Nausea or vomiting
• Muscle cramps
• Dry mouth
• Lack of sweating
• Hard, fast heartbeat

Symptoms of severe dehydration can include mental confusion, weakness, and loss of consciousness. You should get emergency medical attention immediately if you have any of these symptoms.

What is heat illness?

Heat illness can occur when the body is dehydrated and can’t cool itself effectively during exercise in hot or humid weather. There are 3 stages of heat illness:

• Heat cramps
• Heat exhaustion
• Heatstroke

Symptoms of heat cramps include painful muscle spasms in the legs, stomach, arms, or back. Symptoms of heat exhaustion are more serious. They can include faint or weak feelings, nausea, headache, fast heartbeat, and low blood pressure.

The most serious heat-related illness is heatstroke. Symptoms can include high body temperature (higher than 40°C (104°F)), fast heartbeat, flushed skin, fast breathing, and possibly even delirium, loss of consciousness, or seizures. You should get emergency medical attention immediately if you experience any of the symptoms of heatstroke. Untreated heatstroke can lead to death.

How much water is too much?

This depends on your body and the kind of activity you are doing. Talk to your healthcare provider if you have questions about the right amount of water to drink while exercising.

FOR MORE INFORMATION

Dietitians of Canada
https://www.dietitians.ca