Diets, especially those that focus on weight loss, often concentrate on what to eat. But fluids are a major part of any healthy, balanced diet as well. Runners know this well, but the same guidelines apply to anyone interested in optimal health.
About 60% of the human body is water, muscle tissue almost 70%. An enormous range of biochemical reactions inside cells and out require water. Add these facts together and it’s clear that water is a must. No surprise, there. But what might be is how easy it is to have a deficit.
Effects of Dehydration
Lack of proper hydration can have far worse effects than merely feeling thirsty. Headache, fatigue and dizziness are common signs. Heat stroke is serious, potentially fatal – and dehydration is one of the major factors that lead to it.
Nor is it quite good enough to merely wait until you are thirsty to address your fluid need. Elevated internal body temperature, high heart rate and poor motor performance set in when your body has experienced only a 3% weight loss from water deprivation.
In a cool environment, even when you are at rest, your body will lose about 2-3 liters in a day. If you’re active, the number rises to between 3-6 liters. On a warm day, during vigorous activity, the number can be as high as 10 liters. That’s about 3 gallons of water in one day.
How Much Should You Consume and When?
It’s preferable to hydrate in advance. According to the American College of Sports Medicine, that amounts to about 17 ounces (500 ml) every 2 hours for 24 hours prior to any vigorous workout. Another 7-10 ounces (about 200-300 ml) every 20 minutes during exercise is also recommended.
What About Sports Drinks?
Some sports drinks are the perfect form of fluid intake. Just drinking water can lead to harmful dilution of the concentrations of sodium, potassium and other minerals in the body. Among other things, those help regulate the heart and nerve signals. A properly balanced sports drink helps maintain the proper concentration.
But many so-called sports drinks are chock full of sugar. A little bit of simple sugar isn’t bad. It can even be beneficial. But a bottle of sports drink that is really just soda without the bubbles isn’t helpful. Keep that type to a minimum.
Fruit juices can be an effective way of getting needed fluid. But keep in mind that drinks with carbs slow the body’s rate of absorption of water. Here too, the amount of sugar needs to be monitored.
Caffeine and Alcohol
Caffeine drinks aren’t necessarily unhealthy. In fact, in moderation, caffeine has been shown to have definite health benefits. But it’s also a diuretic, a substance that increases urine output. Drinking lots of coffee can actually encourage dehydration. Studies in which participants drank about 6 cups per day (642 mg/day) experienced a 3% loss of body water.
Similarly, alcohol in moderate amounts is beneficial. Red wine has antioxidants. Even beer is healthy, since some of the health effects are due to alcohol alone and hops are good for you. But they do tend also to dehydrate. They’re not a substitute for the total water needed daily.
The body needs several types of nutrients every day, throughout the day: proteins, fats, carbohydrates, vitamins and minerals – and water. Don’t forget the liquid nutrient.