Ok, you think you’re committed to a healthy lifestyle. You make sure to eat plenty of fruits and vegetables, and you’ve cut out most of the saturated fat in your diet. You watch your weight, exercise consistently. Still, you may be neglecting an important component of your body’s health—your hydration.
Think about it. You may be able to recall what you ate yesterday, but can you remember what you drank? While water is a vital nutrient, the majority of Americans don’t consume the amount their bodies need. If you short yourself on water, you may notice the results in the gym—dehydration can impair your exercise performance. Because our bodies need water to function normally, when you’re dehydrated you may feel tired, have trouble concentrating or wind up eating more than usual since our bodies may misinterpret thirst as hunger. And taken to extremes, dehydration can even have life-threatening consequences as a result.
Why We Need Water
While there are countless books devoted to proper nutrition and effective exercise regimes, water is sometimes overlooked as an integral part of any fitness program. "Part of the reason is that many people don’t realize water’s importance for good health," says Kristine L. Clark, Ph.D., director of sports nutrition department at Penn State University. "People don’t realize that water is one of the six classes of nutrients," Clark says. "The average person thinks of water as an insignificant beverage, and it’s very significant. It’s like a vitamin or mineral—if you don’t get enough of it, you’re really missing out."
"There are both health reasons and physical performance reasons that make proper hydration important to all adults and children," says Larry Armstrong, Ph.D., professor of environmental and exercise physiology at the University of Connecticut. "Our bodies are made up of 60 percent water by weight, and we need to maintain that water for proper functioning of our cells and our body organs," Armstrong says. "For example, the circulatory system includes blood, which is primarily water, and the inside of our cells contains primarily water; thus, it’s important to replace the water each day." Our bodies also use water to convert food into energy, remove waste, regulate body temperature and carry nutrients and oxygen throughout our bodies.
The Mechanisms of Thirst
Unfortunately, however, it’s easy to be dehydrated and not even realize it. "We have the ability to mask our thirst mechanism," explains Clark. "And when we do feel thirsty, we’re already about 2 percent dehydrated, so the feeling of thirstiness is actually a symptom of dehydration." (Dehydration is measured in percentages relating to body weight—for example a 150-pound person who is 1 percent dehydrated has lost 1.5 pounds in water weight.)
Just how does the thirst mechanism work? Your brain reads the concentration of your blood constantly, and when your body water level has been reduced by about 1 percent or 2 percent you’ll feel thirsty and presumably drink something. The problem is people often don’t drink enough to make up the difference and maintain that 1 percent to 2 percent level of dehydration over time.
At the gym, this can translate decreased performance. "When you lose about 1 percent of your body weight, your body begins to show signs of strain that it’s experiencing in terms of increased heart rate and increased core body temperature," Armstrong says. "At 3 percent body weight loss, endurance performance begins to decline, and at approximately 5 percent body weight loss, strength and power performance degrade." Even mild dehydration can affect your day-to-day life—you may feel lightheaded, dizzy, tired, headachy and have trouble focusing or concentrating as well.
Getting What You Need
So how much water should you be drinking? It’s probably more than you think—the average sedentary person loses about 2.5 quarts of water a day through ordinary activity alone. And if you exercise, you lose between .8 and 1.5 quarts of fluid each hour in addition to that. All of this fluid must be replaced to maintain optimal hydration.
You’ve probably heard or read that people need eight 8-ounce glasses of water each day, but that’s not necessarily true. "that recommendation came from literature on weight management, but there are no studies proving the average person needs eight 8-ounce glasses of water," Clark says. In fact, your water needs if you are an exerciser are probably higher than this baseline. The American College of Sports Medicine recommends people drink 14 to 22 ounces of fluid two to three hours before exercise, 6 to 12 ounces of fluid every 15 to 20 minutes during exercise, and 16 to 24 ounces of fluid for every pound of body weight lost during exercise.
While water is a great choice, you don’t need to rely on water to satisfy your fluid needs. Beverages like tea, soda, coffee and juice all contribute to your daily total as do foods like soup, fruits and vegetables that are naturally high in water content (just be sure to read the nutrition labels on teas, coffees, juices and soups, as they can also contain sugar, sodium and extra calories). You can increase your intake by having a big glass of water first thing in the morning; keeping a bottle of water on your desk at work; drinking a glass at mid-morning and mid-afternoon; and being sure to drink before, during and after exercise.
There are two ways to easily monitor your own body water status. Weigh yourself first thing in the morning and before and after exercise; then drink a pint of fluid for each pound you lose during your workouts. Or simply pay attention to the volume and color of your urine—it should be straw-colored or pale yellow, says Armstrong.
Make it one of your fitness priorities to aim for optimal hydration. If you’ve been drinking too little, you may notice a marked improvement in the way you look and feel when you increase your water intake. Even if you don’t notice a difference, by drinking more water you’ll be helping your body function at its best.