The adult human body is about 60 percent water, and even light exercise can deplete that percentage, leaving you feeling crummy and interfering with your athletic performance. So, whether you’re hiking, biking, skiing, running, climbing or simply strolling across town, it’s important to hydrate properly. To help you learn how, this article covers:
How much you need to drink depends on a number of factors, such as the activity you’re doing, intensity level, duration, weather, your age, your sweat rate and your body type. A good general recommendation is about a half litre of water per hour of moderate activity in moderate temperatures. You may need to increase how much you drink as the temperature and intensity of the activity rise. For example, strenuous hiking in high heat may require that you drink 1 litre of water or more per hour. As you gain experience, you’ll be able to fine-tune how much you drink.
Dehydration occurs when the loss of body fluids, usually through sweating, exceeds the amount taken in. Once you’ve reached the point of feeling thirsty, dehydration has already begun. If you don’t counteract this by drinking water, the body will continue to provide signs that it is running low on fluids:
Early signs of dehydration:
More serious symptoms of dehydration:
The remedy for dehydration is simple: Drink water. It’s better to take frequent sips of water rather than chugging larger amounts infrequently. Adding in sport/energy drinks can help restore carbohydrates and electrolytes.
Double-check your water intake by weighing yourself before and after exercise: You should weigh about the same. If you have lost several pounds, then you’re probably not drinking enough water. For every pound lost, drink 16–24 fl. oz. of water and plan to increase your fluid intake next time. With that said, it can be very difficult, if not impossible, to maintain your body weight during intense exercise, especially on a hot day, so don’t be surprised if you weigh less.
The flip side to dehydration is over-hydration, or hyponatremia. This is a fairly rare condition that mainly affects endurance athletes such as marathon runners, ultrarunners and triathletes.
In hyponatremia, sodium levels in the blood become so diluted that cell function becomes impaired. In very extreme cases, hyponatremia may cause coma and even death.
The symptoms of hyponatremia are similar to dehydration: fatigue, headache and nausea, causing some athletes to mistakenly drink more water and exacerbate the issue.
Preventing over-hydration: The key to preventing over-hydration is to monitor how much you drink.