Staying well-hydrated is crucial when working out. But does a sports drink offer more benefits than water? The answer depends on the length, type and intensity of exercise and personal preferences. Exercise raises the body temperature, which causes sweating and loss of water and salts.

For most people who work out at moderate intensity for less than 60 minutes, water is a perfect choice. It’s refreshing, calorie-free, moves quickly from the stomach to the bloodstream and costs less than sports drinks.

When it comes to just replacing fluids, water is wonderful. But sports drinks have more going for them than just marketing hype. The carbohydrates and electrolytes they contain can help endurance athletes who work out for 60 minutes at high intensity or 90 minutes or more at moderate intensity.

Sports drinks offer their greatest benefits during a workout by helping to delay muscle fatigue, but their primary purpose is to keep the body hydrated. During exercise, the body loses more water than many people realize, and most frequently those fluids are not adequately replaced.

For this reason, people should not overlook the benefits of water even if they prefer a sports drink during exercise. Before exercising, be sure to drink enough water to prevent beginning a workout with a fluid deficit. Once sweating begins, an athlete probably will not be able to make up that deficit during his or her workout.

If people wait until they are thirsty to take a drink during exercise, they have waited too long. It doesn’t take long for symptoms of mild dehydration to set in. In hot, humid weather, people can become dehydrated in as little as 15 minutes.

Water comprises 60 percent of the body and 80 percent of the muscles. It is the primary component of the blood, helping to transport oxygen and nutrients through the body and waste from the body.

Water also helps to regulate temperature through sweat. For every quart of sweat, the body dissipates roughly 600 calories of heat. A person may sweat between 1 to 2 quarts every hour, depending on his or her weight, intensity of exercise and environmental conditions.

People generally feel thirsty after losing just 1 percent of their body weight through sweat. If water loss reaches 2 to 4 percent, performance may be affected as symptoms of dehydration set in.

Do not wait until thirsty before drinking. By then, it is unlikely the body will be able to replace all the lost fluid as exercise continues. This may cause the exerciser to quit. Water is a perfect choice for fluid replacement. It moves quickly from the stomach into the bloodstream, and people can buy it bottled or get it free from a fountain.

Fitness experts recommend drinking water before working out, even if the exerciser plans to consume a sports drink during exercise. Drink one or two cups of water [8 to 16 ounces (240 to 480 milliliters)] two hours prior to the workout, and another one or two cups a half-hour before exercising. For exercise sessions that last longer than 30 minutes, experts agree that 3 to 6 ounces fluid should be taken every 15 to 20 minutes. Some experts recommend ranges as high as 6 to 12 ounces every 15 to 20 minutes, depending on the activity's intensity.

Along with water as the primary ingredient, a sports drink contains carbohydrates (glucose, sucrose, fructose) and electrolytes (e.g., sodium).

Carbohydrates are the fuel of choice for working muscles. They prevent glycogen (carbohydrates stored in muscles) from being depleted too quickly. When muscle glycogen is depleted, limbs feel heavy, fatigue sets in and the athlete “hits the wall.” A sports drink can provide carbohydrates to help supply the muscles with quick energy and prevent the body from dipping into its glycogen stores.

Electrolytes help increase the absorption of fluid from the gut to the bloodstream. They also replace sodium lost through sweat and maintain plasma volume. A sports drink may contain other minerals, such as potassium and chloride. Although the amount of potassium lost through sweat is not large and can be replaced through normal diet, it may be helpful in preventing some muscle cramping.

A sports drink does a better job than water in staving off fatigue during high-intensity workouts lasting 60 minutes or during prolonged exercise (more than 90 minutes) A good sports drink will contain 5 to 8 percent carbohydrates, which amounts to 50 to 80 calories per 8 ounces (240 milligrams).

Avoid drinks too high in carbohydrates (e.g., soda, fruit juice). The extra carbohydrates can cause stomach discomfort and inhibit absorption of fluid into the bloodstream. Drinks with higher levels of carbohydrates are better consumed after a workout, rather than during exercise activities. This type of drink may cause cramping, gas and diarrhea.

It is important to be aware of symptoms of dehydration to help ensure the safety and effectiveness of a personal workout, as well as to recognize when a workout partner may be in need of fluids. Symptoms of dehydration range from mild and easy to severe and potentially life threatening.

Mild symptoms of dehydration are sometimes slight and easy to miss. Early signs of dehydration may include increased thirst, concentrated dark yellow urine, a dry mouth, headaches, weakness, irritability or cramping. Severe symptoms of dehydration are more blatant and need to be addressed quickly by a healthcare provider. Severe symptoms of dehydration include extreme thirst, no urine or tears, fainting, rapid heart rate, low blood pressure, fast and weak pulse, sunken eyes, altered mental status, and skin dryness.

Preparing questions in advance can help patients to have more meaningful discussions regarding their conditions. Patients may wish to ask their doctor the following questions related to water and sports drinks:

1. Am I staying well hydrated during my workout?
   
   
2. Should I consider a sports drink during my workout?
   
   
3. Do you recommend any particular type of sports drink?
   
   
4. Do you recommend any particular type of bottle water?
   
   
5. How much water or sports drink should I drink during my workout?
   
   
6. Could drinking more water or sports drink improve how I feel following my workout?
   
   
7. How frequently should I pause for a drink during my workout?
   
   
8. Could I be drinking too much sports drink?