Just as we need to have enough sleep our bodies need water to properly function. When not enough water is being drunk we may experience physical illnesses, and in the extreme cases -- death is possible. Figuring out how much water is required by your body and changing developing habits to drink enough are essential for your well being.
By Stas Bekman.
A person's body loses, during an average day in a temperate climate approximately 2.5 litres of water. This can be through the lungs as water vapor, through the skin as sweat, or through the kidneys as urine. Some water is also lost through the bowels. In warm or humid weather or during heavy exertion, however, the water loss can increase by an order of magnitude or more through perspiration -- all of which must be promptly replaced. In extreme cases, the losses may be great enough to exceed the body's ability to absorb water from the gastrointestinal tract; in these cases, it is not possible to drink enough water to stay hydrated, and the only way to avoid dehydration is to reduce perspiration.
A useful rule of thumb for avoiding dehydration in hot or humid environments or during strenuous activity involves monitoring the frequency and character of urination. If one develops a full bladder at least every 3-5 hours and the urine is only lightly colored or colorless, chances are that dehydration is not occurring; if urine is deeply colored, or urination occurs only after many hours or not at all, water intake may not be adequate to maintain proper hydration.
It's known that soda drinks are very dehydrating. Similar is being said about coffee and tea, due to Caffeine's diuretic qualities (it makes you urinate more frequently), but there is a lot of controversy about this subject. Most likely is consumed in moderate dozes it shouldn't be a problem.
When doing intensive sports, one hears a lot about hypotonic and isotonic drinks, which are designed to quickly replace fluids lost through sweating. There are also the hypertonic drinks, which are solutions with a higher carbohydrate electrolyte concentration than body fluids and those aren't good for hydration.
This questions is constantly being discussed at various forums. Here are some interesting opinions from the posters, but first some volume conversion information:
1 gallon = 3.79 litre 100 oz = 2.96 litre
"I drink over a gallon (~4l) of water a day. No soda..no juice...just water!"
"I have been averaging 1 1/2- 2 gallons per day. The women's gym owner got upset at me because she told me that is too much and there really is no need. She said that can make you sick. I ignored her though."
"Half your body weight in ounces is correct. The gym owner is either wrong or she only read the headline of a recent study. The only time you can drink too much water is you are competing in an endurance event and that is usually if it is 15+ miles (~24km). Other notes on water: Don't drink a lot of water or any other liquid for 20-30 minutes prior to meals. It interferes with nutrient absorption. Thirst is a sign of dehydration, so if you are thirsty you probably drink too little water. People sometimes interpret thirst as hunger if they have a history of not getting enough water."
"You can never drink too much water, I learned the hard way! When I was about 20 yrs old I went on a diet, I ate weightwatchers frozen meals and used a stationary bike for exercise everyday for about 7 months and lost over 90lbs! The big problem was (besides losing the weight too fast) I DIDN'T drink enough water, so I developed GALLSTONES at just 20 yrs old! I was studying to be a nurse at the time and diagnosed myself and told the Dr. what I suspected I had, he could not or would not believe me because it was soo unusual at my age to have gallstones. So, after several tests he finally did an ultrasound and sure enough there they were!:shocked: All caused by NOT drinking enough water while dieting! Water is so wonderful in so many ways for your body, please don't underestimate its power."
"The best thing to do is load up on water early. I try to drink 64 oz before 10am, so the rest of the day is easier to reach my gallon and a half."
"The amount of water i drink depends on what on what i do each day. If I'm at work, and i'm at the office all day then I'll drink between 1 to 2 litres of water between 8.30am and 5.00pm If i'm having a factory trial or i'm at the factory playing with machinery, then it's anything between 2-4 litres because its always very hot down there. If i go out for drinks with friends/work colleagues, then i match a glass of water/soft drink for every glass/shot of alcohol i have, or at least i try to remember to do it. If i'm out doing sports, I'll consume an extra 2 litres of my sports drink (just gatorate powder in water) before I've finished a training session for out-rigging/dragon boat or football, or just 1 litre of water if it's just the gym. I don't really aim to drink a specified amount of water per day. I just drink what i need for my body to feel comfortable."
"When you "hyper-hydrate", you can get a condition called hyponatremia. With hyponatremia, water dilutes the sodium in your bloodstream. This condition can be very dangerous because sodium plays a major role in the fluid balance of cells. Symptoms of hyponatermia may be mild and can include bloating, nausea, headaches, and vomiting. More severe symptoms can include coma, brain swelling, respiratory arrest, and death. Add something like gatorade to your daily consumption. It will help keep your sodium levels up."
"The optimum amount of water you should drink depends on your body weight. The fatter you are, the more you need to drink. Take one-half of the amount of your weight in pounds and convert that to ounces and that is how many ounces you should be drinking. Thus, if you weigh 128 pounds, you should be drinking 64 ounces a day. If you weigh 300 pounds, you need to drink 150 ounces a day. You can't just categorize any liquid consumption as being adequate to meet the recommended amount-- for example, coffee is a diuretic and causes you to lose water, so you wouldn't want to try meeting your daily water requirements with large quantities of that."
"If you are unsure if you drink enough water, consult your physician, I was unaware of such a thing and my doctor told me I was drinking too much water when he got the results of my tests during a routine exam."
I'd like to add that if you don't like to drink, you can fruits which are rich with water. Things like melons and watermelons are tasty and will keep you hydrated.
requirements in adults (http://www.water.org.uk/home/water-for-health/ask-about/adults)
Detailed information about water intake recommendations, by Water UK
Substitute for Water (http://www.equipped.com/primer.htm#NoSubstitute)
From a Survival Primer
Symptoms of dehydration explained
Articles on Diarrhoea, Diarrhea, Dehydration, Oral Rehydration, Water, Sanitation and Hygiene
Water Requirements (http://www.water.org.uk/home/resources-and-links/water-for-health/ask-about/adults)
Find out how much water to consume to prevent dehydration
Is water the best choice for post-exercise rehydration?
of dehydration (http://www.nlm.nih.gov/medlineplus/ency/article/000982.htm#visualContent)
by the U.S. National Institutes of Health's MedlinePlus medical encyclopedia