There are different opinions on how much water we should be drinking every day and how frequently. Who is correct? We will try to answer this question from a Urologist's perspective. The body is estimated to have 60% water. We’re constantly losing water from our bodies, primarily via urine and sweat. Health Gurus often advise to have 10 - 12 glasses of water daily. 

Can More Water Increase Energy Levels and Improve Brain Function? 

Even a 1% drop in water in body can cause alterations in brain function and physical performance. For a 70 Kg man this will be around 360 ml, a figure he / she will easily lose in sweat after a moderate morning exercise, so it is a good idea to have good hydration while exercising. 

Does Drinking a Lot of Water Help You Lose Weight? 

There are many claims about water intake having an effect on body weight such as more water increases metabolism and reduces appetite. Researchers estimate that drinking 2 liters in a day can increase energy expenditure by about 96 calories per day. Drinking cold water is the best to burn calories as you will have to expend energy to heat and bring this water to body temperature. Drinking water half an hour before meals can also reduce the amount of calories people end up consuming, especially for older people. Drinking 16 - 18 glasses of water will not detoxify the body or help in losing weight. 

Important: Drinking water can cause mild, temporary increase in metabolism and drinking it about a half hour before meals can make people automatically eat fewer calories. 

Does More Water Help Prevent Health Problems? 

Some health problems that may respond well to increased water intake:

  • Constipation: Increasing water intake can help with constipation, which is a very common problem.

  • Kidney stones: Regular water intake throughout the day appears to be the single most important factor to decrease the risk of kidney stones.

  • Cancer: Doubtful benefit for Bladder Cancer / Colon Cancer.

  • Acne and skin hydration: There are a lot of anecdotal reports on the internet about water helping to hydrate the skin and reducing acne, but no studies to confirm or refute this can be found. Stop listening to your beautician who says lot of water is good for your skin. 

Important: Drinking more water may help with only some health problems, such as constipation and kidney stones. 

Do Other Fluids Count Toward Your Total? 

Plain water is not the only thing that contributes to fluid balance, other drinks and foods can also have a significant effect. Most foods also are also full of water, especially, meat, fish, eggs, citrus fruits and vegetables. One myth is that tea and coffee don’t count because caffeine produce more urine. Frequent urination is because of the volume added and not caffeine. 

Important: If you drink coffee or tea and eat water-rich foods, then chances are that this alone is enough to maintain fluid balance, as long as you don’t sweat much. 

Trust Your Thirst. It’s There For a Reason.

Maintaining water balance is essential for our survival. This is controlled by mechanisms similar to things like breathing. We don’t need to consciously think about it. 

For the majority of people, there probably isn’t any need to worry about water intake at all. When our total water content goes below a certain level, thirst kicks in. There really is no actual science behind the 10 - 12 glasses a day rule. It is arbitrary. 

That being said, there are certain circumstances that may call for increased water intake. The most important one may be during times of increased sweating. Water need is also increased during breastfeeding, as well as during diseases such as vomiting and diarrhea. Older people may need to consciously watch their water intake, because some studies show that the thirst mechanisms can start to malfunction in old age. 

Bottom Line: Most people don’t need to consciously think about water intake, because the thirst mechanism in the brain is very effective. However, certain circumstances do call for increased intake. 

How Much Water is Best? 

At the end of the day, no one can tell you exactly how much water you need. As with most things, this depends on the individual. Do some self permutation, some people may function better with more water than usual, while for others it only causes the inconvenience of more frequent trips to the bathroom. 

If you want to keep things simple (always a good idea), then these guidelines should apply to 90% of people: 

  1. Drink evenly throughout the day, drinking 2000ml of water in one go is of no use. 
  2. When thirsty, drink. 
  3. When not thirsty anymore, stop. 
  4. Along with food, you do not need to drink water for “better digestion”. 

  5. During high heat and exercise, drink enough to compensate for the lost 
  6. As you grow old it might be better to avoid drinking too much of water in 
late evenings, it will only mean more frequent night time bathroom visits. 
  7. Remember - Water and Urine are like hand in glove. They go together. No right and No wrong - As in marriage, so in water.