While it is very important for us to understand the types of foods that we consume, it is also is good for us to learn about the importance of water to our bodies. Today I want to talk all about water; about its functions, its absorption into our bodies, the importance of staying hydrated, and especially the importance of hydration during exercise.
In our bodies, water serves as a body transport system, for both gas exchange and nutrient absorption. All food products contain some amount of carbohydrates, lipids, proteins, vitamins, and minerals, but they also contain a certain amount of water (called water content). Different foods contain different amounts of water. The higher the amount of water, the lower the food item is in calories and usually the higher it is in nutrients. This is especially good for nutrient absorption because we can eat more of these lower calorie, higher nutrient food items, and more nutrients will be absorbed into the body. What kinds of foods have a higher water content? Mostly fruits and vegetables! For example lettuce is 95.8% water and 3.7 calories, compared to chocolate fudge which is only 8.1% water and 115 calories. On a caloric level, we can eat a lot more nutrient and vitamin rich lettuce than high calorie chocolate.
In terms of absorption, we ingest about 2 liter of water a day! On top of that, our saliva, gastric secretions, bile, pancreatic secretions, and intestinal secretions contribute another 7 liters of water a day. Of these 9 liters of water that go into our bodies on a daily basis, not all of it is absorbed. Sometimes, the other nutrients in our foods; like salt, some amino acids, and some of the sugar in our drinks actually blunt water absorption. Salt can also cause us to retain more of water than we should which causes us to have higher blood pressure. In order to combat this, simply reduce salt intake!
Another danger with excess water intake (ingesting more than 10 quarts of water a day) is hyponatremia, or water intoxication. Hyponatremia causes significant dilution of the body's normal sodium concentration; leaving us with symptoms such as headache, blurred vision, excessive sweating, and vomiting. In severe cases of hyponatremia, people can experience cerebral edema, convulsions, comatose, and even death! In light cases, hyponatremia can be combated by restricting water consumption until the body is back to normal. In more severe cases, a doctor should be consulted!
In terms of exercise, it is important to know how fluids are lost and why we need to replace them. Water is extremely important for exercise because it allows us to sweat in order to cool our bodies down. Therefore, we need to maintain water and plasma volume so that circulation and sweating can progress at optimal levels. If we do not, we have the possibility of reaching dehydration which could then lead to heat disorders. To help defend against dehydration while you are working out, remember to keep your sweaty clothes on because changing to dry clothes actually hinders evaporative cooling, and to drink water regularly, especially during exercises lasting 60 minutes or longer. Since our thirst mechanism does not always match our level of our hydration, it is better to consume more fluids than thirst dictates in order to stay completely hydrated.
During exercise, there are two kinds of balances that we need to maintain: water balance and electrolyte balance. As our metabolic rate increases, so does the metabolic water production which leads to more water gain. During exercise, water loss is increased due to sweating. When water loss increases, blood flow to the kidneys also decreases to prevent dehydration and urine output is reduced. If dehydration exceeds 2% of body weight, our physical performance is actually impaired. Therefore, to have optimum physical performance, we must keep our body's water content in balance. The loss of water from sweating also disrupts the electrolyte balance in our bodies, through the loss of the electrolytes sodium and chloride. During exercise, excess electrolytes are excreted in both urine as well as sweat. The body responds by promoting renal retention of sodium and chloride ions in storage. Therefore, it is also important to keep balance in the bodies electrolytes during exercise to prevent excess storage of sodium and chloride.
Drink manufacturers have thus created drinks to help us maintain both water and electrolyte balance while we exercise by adding carbohydrates to our fluids. Concentrations of 11 grams or less of carbohydrates per 100 mL of fluids don't really supply the needed energy for prolonged exercise. However, drinking fluids with 4 to 8 grams of carbohydrates per 100 mL fluids every 10 to 15 minutes during exercise can reduce the risk of dehydration and can provide a partial energy supplement. But, during prolonged exercise water intake is the primary concern for athletes. Sport drinks also contain glucose polymers. These help to provide water and carbohydrates at a faster rate to the body.
Before the body can absorb water through the small intestine, fluids must first be emptied from the stomach. Three things have influence over this emptying of the stomach, also called gastric emptying. The first is fluid temperature. The colder the water, the faster it empties from the stomach. Fluid volume also affects the speed of emptying; drinking too much volume of fluids can slow gastric emptying. Therefore, try to only drink 8.5 ounces every 15 minutes to keep the volume of fluids in the stomach down. Finally, the osmolarity of fluids can slow fluid emptying when its osmolarity is higher than 10% (glucose polymers have low osmolarity). Therefore, the best things we can drink to increase absorption is a small (8.5 oz), cold drink with low osmolarity.
Finally, with exercise and hydration, we also need to know how our body deals with exercise in different weather environments and how to prevent injuries from excess heat and low water intake. In environments where the temperatures are high and the atmosphere is very humid, the body can't loose heat as easily from evaporation and is much more susceptible to heat stroke. Therefore, it is vital to be aware of the humidity in your area before deciding when is the best time to workout. In addition to knowing what time is best for exercise, you can also prevent heat stress injuries by becoming acclimated to the environment before working out, by staying hydrated, and by having a little bit of salt to prevent electrolyte imbalance. In addition to helping keep the body's temperature down, staying hydrated also helps to lower the heart rate during exercise and allows us to exercise at a higher intensity.
In general, water is not only important for maintaining good health but also for maintaining optimum levels of exercise. Water makes up 70% of our body mass and therefore needs to be a vital component to our daily diets. So remember as you are deciding on what you need to consume, to make sure you are consuming the required amount of fluids… plus some! And if you are an athlete, drink lots more water than normal! After all, exercise makes water taste good!
Today's Workout: Still not feeling well today… If you are though, today is Monday which means it is Yoga day! Pop in a video or attend a class. Enjoy the strengthening and lengthening of your muscles as you complete the workout. Try making this workout about an hour long. If that still isn't enough, you can also run two miles or so to get some cardio working out going. Hope you all have a good workout. I'm totally bummed I can't today!
Today's Food Tip: Here is another tip for sick food. If your throat is ever sore and it is hard to swallow, popsicles are an amazing source of fluids and will help cool your throat down. I had some today and they were super good!
Today's Relaxation Activity: Today I did a lot of lying around and trying to get better. If you are not feeling well and just lying around a lot, look up some good movies on TV or pop in a DVD. Watching a good film will help take your mind off of not feeling well. So enjoy the movie night!
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