The human body is mostly water: about 55% to 75%, on average (and depending on how well-hydrated you are). That’s about 10 to 12 gallons of water in your body! Water makes up about 83% of blood, 73% of muscles, 25% of body fat, and 22% of bone.
The Institute of Medicine recommends that men get about 125 ounces of water daily and that women get 91 ounces, but that includes water from all foods and beverages
The average person gets about 20% of their water for the day from food. An apple is 84% water. Bananas are 74% water. Broccoli is 91% water.
On average, you should take a rehydration break about every 20 minutes. Most people would stay adequately hydrated by drinking 5 to 10 ounces of fluid every 20 minutes. But your exact need depends on things like how hard you’re working, whether you are indoors or outdoors, and your age, gender, and weight.
It’s also helpful to drink two cups of fluids (about 16 ounces) about two hours before a workout
Alcoholic beverages have the most dehydrating effect. Coffee and other caffeinated drinks do make you urinate more, but overall, they’re less dehydrating because of their water content. Juices, sodas, and other sweet drinks also are dehydrating. Water is usually a better choice for hydration because it doesn’t have extra calories.
How much fluid you need depends upon several things, including:
Age: Kids need plenty of fluids; they can get dehydrated much more easily than adults. Older people may need more fluids because of health conditions or because they tend to lose their sense of thirst.
Gender: Men need more fluids than women. (Pregnant women need more fluids than other women.)
Weight: Heavier people need more water.
Health: Conditions such as diabetes, cystic fibrosis, and kidney disease can boost your need for fluids.
Environment: You need more fluids in extreme weather conditions (especially hot, humid, or cold) and at high altitudes. You lose about 10 or more cups of water every day just living: breathing, sweating, urinating, etc. Eating and drinking usually make up for it.
An easy way to monitor your hydration level is to check the color of your urine. The darker your urine, the less hydrated you are. Drink enough fluids to keep your urine a lighter color. If your urine is clear or pale, chances are you are well hydrated.
Other practical ways to monitor your hydration status include keeping an eye on your body weight (you lose weight as you lose water) and perspiration (the more you perspire, the more water you’re losing).
It is possible to drink too much water. Healthy kidneys in an adult can process anywhere from 20 to 1,000 milliliters of fluid per hour. It’s not easy to overload them, but it can happen. Getting too much water, especially in a short time, is dangerous. Symptoms of too much water include weight gain, bloating, nausea, and vomiting. Sudden cases of water intoxication can cause low blood sodium, which can result in headaches, confusion, seizures, and coma.
The International Marathon Medical Directors Association recommends that athletes drink no more than 31 ounces of water per hour during extended exercise
Your body has water in every cell, tissue, and organ. It helps move nutrients, get rid of waste, keep your temperature at the right level, lubricate and cushion joints, keep your skin moisturized, and lots of other things.
Thirst is one of the first warning signals that you may be getting dehydrated. But don’t rely on thirst alone. Other early signs are fatigue, flushed skin, faster breathing and pulse rate, and trouble exercising. Later signs include weakness, dizziness, and labored breathing.
If you think you’re becoming dehydrated, you should move to a cool place and rehydrate. Drink fluids slowly — drinking too fast can stimulate urination, resulting in less hydration
Water is usually enough to rehydrate unless you’re exercising really hard or for a long time. Athletes tend to replace only about half of the fluid lost when they drink water. Sports drinks may replace more lost fluids because athletes enjoy the taste