Healthy Hydration for Summer Exercise

We’re heading into summer. That means many of us will be spending a lot of time outdoors exercising so that we can enjoy the very best of summer. It also means that we can experience exceptionally high temperatures with significant differences in humidity, all of which we need to do a little planning for. Being hydrated is a critical component of that planning, and consuming the right amount of liquid before, during and after exercise will help our bodies stay comfortable, perform well and avoid the health risks associated with too much or too little fluid.

How Much is the Right Amount?  
A review of research done by major universities and the American College of Sports Medicine on the question of how much is the right amount comes out to the unsatisfying answer of “that depends.” The right amount depends on variables such as an individual’s physiology, level of fitness and acclimation to summer weather; the weather itself, the type of activity, and the duration of the activity.

Adequate Fluid Intake for Athletes: Forget About Thirst
Because there is wide variability in sweat rates, losses and hydration levels of individuals, it is nearly impossible to provide specific recommendations or guidelines about the type or amount of fluids athletes should consume. As a result, an athlete needs to actively monitor their body functions during exercise to assess how effective their current hydration plan is working.

And, thirst is not a great indicator. The American College of Sports Medicine (ACSM) released a statement noting that “thirst is important during and after physical activity, especially in hot environmental conditions,” said ACSM President W. Larry Kenney, Ph.D. “How-ever, the clear and important health message should be that thirst alone is not the best indicator of dehydration or the body’s fluid needs.” To minimize the potential for heat exhaustion and other forms of heat illness, Kenney and other ACSM experts recommend two strategies for monitoring hydration. They include:

Urine color and volume. While not a perfect tool for measuring hydration, in general, a large amount of light-colored, diluted urine probably means you are hydrated; dark-colored, concentrated urine probably means you are dehydrated.
Weight. Weigh yourself before and after exercise because if any weight is lost, it is likely from fluid loss. You need to drink enough to replenish those losses and ACSM experts note that consuming “beverages containing electrolytes and carbohydrates can help sustain fluid electrolyte balance and exercise performance.” A weight gain, however, could mean you are drinking more than you need.

What about Sports Drinks?
For athletes working out intensely for longer than an hour, sports drinks can be useful. Fluids supplying 60 to 100 calories per 8 ounces help provide needed calories required for continuous performance. In most cases, it’s really not necessary to replace losses of sodium, potassium and other electrolytes during exercise as you are unlikely to deplete your body’s stores unless you are racing in a marathon, Ironman or other similar endurance activity lasting more than three hours.

General Guidelines for Fluid Needs During Exercise
While specific fluid recommendations aren’t possible due to the wide range of individuals’ needs, exercise levels, level of fitness, weather and more, most athletes can use the following guidelines as a starting point, and modify their fluid needs accordingly.

Hydration Before Exercise
–Drink about 15-20 fl oz, 2-3 hours before exercise.
–Drink 8-10 fl oz, 10-15 minutes before exercise.
Hydration During Exercise
–Drink 8-10 fl oz every 10-15 minutes during exercise.
–If exercising longer than 90 minutes, drink 8-10 fl oz of a sports drink (with no more than 8 percent carbohydrate) every 15 – 30 minutes.
Hydration After Exercise
–Weigh yourself before and after exercise and replace fluid losses. Drink 20-24 fl oz water for every 1 pound lost.
–Consume a 4:1 ratio of carbohydrate to protein within the 2 hours after exercise to replenish glycogen stores.

Treating Heat Stroke
Treating heat stroke immediately is essential. You should immediately stop whatever you are doing and find a cool place to rest, drink plenty of cool water, or take a shower using cool water (or jump in a pool or turn on a garden hose).

Preventing Heat Stroke
The best way to prevent heat stroke is to prevent heat exhaustion. This includes slowly getting used to hot weather, drinking plenty of fluids so you can stay hydrated and working out during cooler parts of the day. Make sure to hydrate well both before you exercise and after you finish, paying particular attention to adding in electrolytes like magnesium, sodium and potassium with your food or sports drink. A general rule – and remember, each situation is different – drink 16 to 20 oz every hour.