Water and Physiology
The human body is mostly water, which forms the supportive basis for many of the cellular structures that our bodies are built upon—and our bodies depend upon proper water balance to thrive. In other words, water is essential for the maintenance of homeostasis (proper physiological balance within and throughout the body). An adequate level of hydration helps our digestion function better, helps the body with thermoregulation, and helps to keep us more alert. It also brings nutrients to cells via the blood and waste products away from organs.
Water helps control the osmotic pressure of the body, which ensures that the balance between water and electrolytes (sodium, potassium, etc.) is maintained. In sport and fitness, problems in this balance are most often seen regarding sodium balance. Hyponatremia, or very low levels of sodium in relation to water in the body, can in worst cases be fatal. It can result in coma and, as sodium is essential in nerve function, decreased nervous system activity. Hypernatremia, or very high levels of sodium in relation to water in the body, can also be very dangerous. It is most often caused by dehydration and can result in heat cramps (which could also be caused because of potassium and calcium imbalance as well as that of sodium). On the cellular level, this causes cells to shrivel and die on account of letting go of water in an attempt to even out the water/sodium ratio in intercellular spaces. Severe dehydration can also cause conditions such as heat exhaustion and life-threatening heat stroke. (Heat stroke results in thermoregulatory failure and is marked by a body temperature of higher than 105 F.)
With all of this being said, the importance of water intake is of utmost importance to anyone—especially those who exercise and spend time out in the heat. When one exercises at high intensities or spends time in hot environments, a great deal of fluid is lost as sweat. Sweat is the body’s inherent cooling mechanism, and those who train more increase their sweat production. This is beneficial for thermoregulation, heaping the athlete's body to become more efficient at cooling itself. This being said, the well-trained athlete must take care to rehydrate properly during training and competition to off-set fluid losses. Also lost in sweat are electrolytes such as sodium, potassium, and chloride, and it is for this reason that sports drinks contain sodium and potassium. If the athlete only rehydrates with water when sweating profusely, they risk hyponatremia. With the inclusion of electrolyte replacement, though, this risk is largely decreased. It is important to note that those who exercise regularly improve their ability to maintain sodium and lose less of it in sweat, which can lead to a more beneficial sodium balance within the body.
How Much Water?
An adequate intake of water is absolutely essential for everyone, but especially for the athlete or those in physically demanding occupations. Nutritionist Dr. Mike Roussell calls water “the best performance enhancing ‘drug’ out there.” Not only should the athlete consume water during training and competition, but he or she should maintain an adequate level of hydration throughout the day. How much do we need to drink a day? There isn't a clear one-size-fits-all answer, but what is clear is that thirst is usually an indication that our bodies have been in need of water. In other words, as Dr. Roussell says, “Never allow yourself to be thirsty. If you find yourself thirsty, you are already on your way to becoming dehydrated.”
To prevent this, it would be prudent for the athlete (and everyone for that matter) to find a level of water intake throughout the day which allows them to consistently feel hydrated. This could mean drinking your entire 20-ounce water bottle every 2 to 4 hours. Mark Verstegen, widely recognized as one of the top strength and conditioning coaches in the world, recommends consuming a gallon of water per day. However you accomplish this, it is of utmost importance. (As important as it is to avoid dehydration, it is also important to avoid overhydration, which can cause electrolyte imbalances in the body, and in a worst-case scenario, kidney failure and death.)
Hydration Strategies - Key Takeaways
Hydrate throughout the day, not just right before, during, or after exercise.
Strangely enough, you can tell whether you're hydrated enough by the color of your urine - the lighter it is, the more hydrated you likely are, and the darker it is, the more dehydrated. Gross, yes, but effective!
Checking your weight before and after practice or a workout can give you key info about whether or not you're staying hydrated during exercise. Replacing your fluid loss is very important - the American Council on Exercise, for example, recommends that for every pound lost during training, you intake 16 to 24 ounces of fluid afterwards. If you lose more than a three or four pounds after exercise, though, up your hydration during your next practice or workout (severe dehydration can greatly impair athletic performance and be a health risk!)
When your training or competition is out in the heat and/or it lasts more than about an hour, replacing electrolytes and getting in sugars during the activity is key - this is why drinks like Gatorade and Powerade have electrolytes and sugars in them.
Avoiding sugary sports drinks except around training/competition time is very important. Save the Gatorade for during and after a strenuous workout - otherwise you're basically drinking soda!
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