Exercise and Hydration Status
Water is essential to every day life. It has many important functions in the body such as:
Eliminating waste
Transporting nutrients
Lubricating and cushioning joints
Moisturizing skin and tissues
Regulating body temperature through sweat
Aiding in digestion
Helping to strengthen muscles
Since water is so important to a healthy lifestyle, being properly hydrated is crucial, especially during times of physical activity. What many of us do not realize is that thirst is not the best indicator of how much fluid we actually need! Especially as we age, thirst becomes an even poorer indicator of the body’s fluid needs. Therefore, we need to be aware of our fluid consumption, whether exercising or not. Proper hydration status helps regulate body temperature and consuming fluids before, during, and after exercise help to replace body fluids lost through sweat. Dehydration can result when athletes do not properly replenish fluids during exercise. Signs of dehydration include:
Muscle cramps
Dizziness and lightheadedness
Headaches
Nausea
Fatigue
Heat illnesses such as heat exhaustion or heat stroke
It is important to recognize certain situations that can alter fluid losses during exercise. High altitudes increase your fluid losses and therefore increases your fluid needs. Exercising in hot temperatures increases your sweating rate and therefore increases your fluid needs. Cold temperatures can make your fluid requirements deceiving. Exercising in the cold often makes it hard to identify your fluid losses and needs, so make sure to drink plenty of water, even if you’re not sweating as much. Everyone has a different sweating rate and if you sweat a lot, you are at a greater risk for dehydration. But just because you don’t sweat a lot, doesn’t mean you’re in the clear. Make sure you weigh yourself before and after exercise to monitor your fluid needs. Lastly, exercise duration and intensity may increase your fluid needs. Endurance activities require you to drink more frequently to avoid dehydration.
Optimal performance cannot occur when an athlete is dehydrated. And since sweat rates and fluid losses vary among individuals, it is near impossible to create guidelines on how much fluid to consume during exercise. Therefore, each person needs to monitor their own hydration using the following two methods:
Monitor urine volume output and color. If your urine is a dark color, it probably means you are dehydrated. Light-colored urine, along with frequent urination, probably means you are adequately hydrated.
Weight yourself before and after exercise. Any weight that is lost during exercise is probably due to sweating. You want to replace fluids at a rate close to or equal to your sweating rate.
General guidelines have been created for fluid needs during exercise. Most people can use these guidelines as a starting point and then modify them according to their activity level and need. Two to three hours before exercise, consume 15-20 fl oz of water and 10-15 minutes before exercise, consume 8-10 fl oz of water. During exercise, it is important to drink 8-10 fl oz every 10-15 minutes of exercise. Those requirements will increase with exercise intensity and when exercising longer than 90 minutes. In that case, you may need to supplement your water consumption with a sports drink. After exercise, weigh yourself to determine your fluid losses (remember to weigh yourself before you start, as well). For every 1 lb lost, drink 20-24 fl oz of water. You may also want to consume a 4:1 ratio of carbohydrate to protein within the first 2 hours after exercise to replenish glycogen stores. Obviously not the topic of this article, but glycogen is the fuel your muscles use when exercising, so it’s important to replenish those stores, along with your fluid losses!
The next question that arises is whether sports drinks are necessary in replenishing fluid losses and can they be used instead of drinking plain water. Sports drinks are not necessary with normal training. During normal exercise, you do not need to replenish your electrolytes (sodium and potassium) because it is unlikely that you will deplete your body’s stores. However, high intensity exercise for more than 60 minutes or extreme exercise conditions such as a marathon may require supplemental calories and electrolytes from a sports drink for continual performance. Remember that some sports drinks are high in sugar and calories, which often defeats the purpose of every day exercise. Water is sufficient in replenishing fluid losses from exercise and will not provide any unneeded calories!
Remember, whether you are an avid exerciser or not, keep drinking water! Just because you are not thirsty, does not mean you are adequately hydrated. If you struggle getting in your 8-10 glasses of water a day, try keeping a water bottle on your desk. If it’s there, you’ll drink it!
References:
Quinn E. 2009. Proper Hydration for Exercise – Water or Sports Drinks. About.com. http://sportsmedicine.about.com/od/hydrationandfluid/a/ProperHydration.htm
Quinn E. 2007. ACSM Clarifies Indicators for Fluid Replacement. About.com. http://sportsmedicine.about.com/cs/hydration/a/022504.htm
Exercise and Fluid Replacement. 2007. ACSM Position Stand, American College of Sports Medicine. Medicine and Science in Sports & Exercise.
Institute of Medicine. 2005. Dietary Reference Intakes for Water, Sodium, Chloride, Potassium and Sulfate. National Academy Press 73-185.
Johnson M. Fluids and Hydration. University of Minnesota Extension Service. http://www.extension.umn.edu/family/W00031.pdf
Hunter JG and Cason KL. 2009. Fluid Needs. Clemson Cooperative Extension. http://www.clemson.edu/extension/hgic/food/nutrition/nutrition/special_needs/hgic4151.html
Water is essential to every day life. It has many important functions in the body such as:
Eliminating waste
Transporting nutrients
Lubricating and cushioning joints
Moisturizing skin and tissues
Regulating body temperature through sweat
Aiding in digestion
Helping to strengthen muscles
Since water is so important to a healthy lifestyle, being properly hydrated is crucial, especially during times of physical activity. What many of us do not realize is that thirst is not the best indicator of how much fluid we actually need! Especially as we age, thirst becomes an even poorer indicator of the body’s fluid needs. Therefore, we need to be aware of our fluid consumption, whether exercising or not. Proper hydration status helps regulate body temperature and consuming fluids before, during, and after exercise help to replace body fluids lost through sweat. Dehydration can result when athletes do not properly replenish fluids during exercise. Signs of dehydration include:
Muscle cramps
Dizziness and lightheadedness
Headaches
Nausea
Fatigue
Heat illnesses such as heat exhaustion or heat stroke
It is important to recognize certain situations that can alter fluid losses during exercise. High altitudes increase your fluid losses and therefore increases your fluid needs. Exercising in hot temperatures increases your sweating rate and therefore increases your fluid needs. Cold temperatures can make your fluid requirements deceiving. Exercising in the cold often makes it hard to identify your fluid losses and needs, so make sure to drink plenty of water, even if you’re not sweating as much. Everyone has a different sweating rate and if you sweat a lot, you are at a greater risk for dehydration. But just because you don’t sweat a lot, doesn’t mean you’re in the clear. Make sure you weigh yourself before and after exercise to monitor your fluid needs. Lastly, exercise duration and intensity may increase your fluid needs. Endurance activities require you to drink more frequently to avoid dehydration.
Optimal performance cannot occur when an athlete is dehydrated. And since sweat rates and fluid losses vary among individuals, it is near impossible to create guidelines on how much fluid to consume during exercise. Therefore, each person needs to monitor their own hydration using the following two methods:
Monitor urine volume output and color. If your urine is a dark color, it probably means you are dehydrated. Light-colored urine, along with frequent urination, probably means you are adequately hydrated.
Weight yourself before and after exercise. Any weight that is lost during exercise is probably due to sweating. You want to replace fluids at a rate close to or equal to your sweating rate.
General guidelines have been created for fluid needs during exercise. Most people can use these guidelines as a starting point and then modify them according to their activity level and need. Two to three hours before exercise, consume 15-20 fl oz of water and 10-15 minutes before exercise, consume 8-10 fl oz of water. During exercise, it is important to drink 8-10 fl oz every 10-15 minutes of exercise. Those requirements will increase with exercise intensity and when exercising longer than 90 minutes. In that case, you may need to supplement your water consumption with a sports drink. After exercise, weigh yourself to determine your fluid losses (remember to weigh yourself before you start, as well). For every 1 lb lost, drink 20-24 fl oz of water. You may also want to consume a 4:1 ratio of carbohydrate to protein within the first 2 hours after exercise to replenish glycogen stores. Obviously not the topic of this article, but glycogen is the fuel your muscles use when exercising, so it’s important to replenish those stores, along with your fluid losses!
The next question that arises is whether sports drinks are necessary in replenishing fluid losses and can they be used instead of drinking plain water. Sports drinks are not necessary with normal training. During normal exercise, you do not need to replenish your electrolytes (sodium and potassium) because it is unlikely that you will deplete your body’s stores. However, high intensity exercise for more than 60 minutes or extreme exercise conditions such as a marathon may require supplemental calories and electrolytes from a sports drink for continual performance. Remember that some sports drinks are high in sugar and calories, which often defeats the purpose of every day exercise. Water is sufficient in replenishing fluid losses from exercise and will not provide any unneeded calories!
Remember, whether you are an avid exerciser or not, keep drinking water! Just because you are not thirsty, does not mean you are adequately hydrated. If you struggle getting in your 8-10 glasses of water a day, try keeping a water bottle on your desk. If it’s there, you’ll drink it!
References:
Quinn E. 2009. Proper Hydration for Exercise – Water or Sports Drinks. About.com. http://sportsmedicine.about.com/od/hydrationandfluid/a/ProperHydration.htm
Quinn E. 2007. ACSM Clarifies Indicators for Fluid Replacement. About.com. http://sportsmedicine.about.com/cs/hydration/a/022504.htm
Exercise and Fluid Replacement. 2007. ACSM Position Stand, American College of Sports Medicine. Medicine and Science in Sports & Exercise.
Institute of Medicine. 2005. Dietary Reference Intakes for Water, Sodium, Chloride, Potassium and Sulfate. National Academy Press 73-185.
Johnson M. Fluids and Hydration. University of Minnesota Extension Service. http://www.extension.umn.edu/family/W00031.pdf
Hunter JG and Cason KL. 2009. Fluid Needs. Clemson Cooperative Extension. http://www.clemson.edu/extension/hgic/food/nutrition/nutrition/special_needs/hgic4151.html
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