Benefits of staying hydrated

Water accounts for 60 percent of your body and is essential to every cell. Research has suggested that staying hydrated keeps your memory sharp, your mood stable and your motivation intact. You can also think through a problem more easily. Staying hydrated doesn’t just impact your brain, though. Here are a few ways water benefits your body’s health.

Water keeps your throat and lips moist and prevents your mouth from feeling dry. Dry mouth can cause bad breath and/or an unpleasant taste–and can even promote cavities.

Dehydration lowers your blood volume, so your heart must work harder to pump the reduced amount of blood and get enough oxygen to your cells, which makes everyday activities like walking up stairs–as well as exercise–more difficult.

Your body releases heat by expanding blood vessels close to the skin’s surface (this is why your face gets red during exercise), resulting in more blood flow and more heat dissipated into the air. When you’re dehydrated, however, it takes a higher environmental temperature to trigger blood vessels to widen, so you stay hotter.

When you’re well hydrated, the water inside and outside the cells of contracting muscles provides adequate nutrients and removes waste efficiently so you perform better. Water is also important for lubricating joints. Contrary to popular belief, muscle cramps do not appear to be related to dehydration, but, instead, to muscle fatigue, according to Sam Cheuvront, Ph.D., an exercise physiologist.

When a person is severely dehydrated, skin is less elastic. This is different than dry skin, which is usually the result of soap, hot water and exposure to dry air. And, no, unfortunately, drinking lots of water won’t prevent wrinkles.

Your kidneys need water to filter waste from the blood and excrete it in urine. Keeping hydrated may also help prevent urinary tract infections and kidney stones. If you are severely dehydrated, your kidneys may stop working, causing toxins to build up in your body. Dehydration can have a noticeable effect if you lose as little as 2% of your body's water content. However, it is not uncommon for athletes to lose up to 6-10% of their water weight via sweat.

This can lead to altered body temperature control, reduced motivation, increased fatigue and make exercise feel much more difficult, both physically and mentally. Optimal hydration has been shown to prevent this from happening, and may even reduce the oxidative stress that occurs during high intensity exercise. This is not surprising when you consider that muscle is about 80% water. So, if you exercise intensely and tend to sweat, then staying hydrated can help you perform at your absolute best. Losing as little as 2% of your body's water content can significantly impair physical performance.

Your brain is strongly influenced by hydration status. Studies show that even mild dehydration (1 - 3% of body weight) can impair many aspects of brain function. In a study of young women, fluid loss of 1.36% after exercise impaired both mood and concentration, and increased the frequency of headaches.

Another similar study, this time in young men, showed that fluid loss of 1.59% was detrimental to working memory and increased feelings of anxiety and fatigue. Many other studies, ranging from children to the elderly, have shown that mild dehydration can impair mood, memory and brain performance. Mild dehydration (fluid loss of 1 - 3%) can impair energy levels and mood, and lead to major reductions in memory and brain performance.

Dehydration can trigger headaches and migraines in some individuals. Several studies have shown that water can relieve headaches in those who are dehydrated. However, this appears to depend on the type of headache. One study of 18 people found that water had no effect on the frequency of headaches, but did reduce the intensity and duration somewhat.

Constipation is a common problem, characterized by infrequent bowel movements and difficulty passing stool. Increasing fluid intake is often recommended as a part of the treatment protocol, and there is some evidence to back this up. Low water consumption appears to be a risk factor for constipation in both young and elderly individuals. Carbonated water shows particularly promising results for constipation relief, although the reason is not entirely understood.

Urinary stones are painful clumps of mineral crystal that form in the urinary system. The most common form is kidney stones, which form in the kidneys. There is limited evidence that water intake can help prevent recurrence in people who have previously gotten kidney stones. Higher fluid intake increases the volume of urine passing through the kidneys, which dilutes the concentration of minerals, so they are less likely to crystallize and form clumps. Water may also help prevent the initial formation of stones, but studies are required to confirm this.

A hangover refers to the unpleasant symptoms experienced after drinking alcohol. Alcohol is a diuretic, so it makes you lose more water than you take in. This can lead to dehydration. Although dehydration is not the main cause of hangovers, it can cause symptoms like thirst, fatigue, headache and dry mouth. A good way to reduce hangovers is to drink a glass of water between drinks, and to have at least one big glass of water before going to bed.

Drinking plenty of water can help you lose weight. This is due to the fact that water can increase satiety and boost your metabolic rate. In two studies, drinking half a liter of water was shown to increase metabolism by 24-30% for up to 1.5 hours. This means that drinking 2 liters of water every day can increase your total energy expenditure by up to 96 calories per day. The timing is important too, and drinking water half an hour before meals is the most effective. It can make you feel more full, so that you eat fewer calories.

In one study, dieters who drank half a liter of water before meals lost 44% more weight, over a period of 12 weeks. It is actually best to drink water cold, because then the body will use additional energy (calories) to heat the water to body temperature.