Vispi Speaks: How Much Water Do You Really Need To Drink


January 29, 2020

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Vispi Kanga

Hydration is important, especially in hotter regions where people lose more water from sweating and exhalation. There are plenty of clear associations between hydration and metabolism, skin health, and general fitness.  But too much of anything isn’t good. Even water. So, how much is the right amount of water you should drink?

vispi-kanga-295x295A couple of human studies have suggested that individuals who drink very, very small amounts of fluid, significantly less than 800-900 mL/day, may be at higher risk for some cardiovascular diseases, perhaps bladder cancer, and strokes.  On the other hand, there is no evidence that people who consume normal amounts of water and have urine outputs of over 1 L/day are healthier when their outputs are 2-3 L/day. The most recent epidemiologic studies[4] that have been conducted have suggested that increased water intake is not associated with better cardiovascular outcomes or improved mortality.

Lay press has promoted the “urban myth” that not only should you drink 6-8 glasses of water a day as a typical intake, but in addition you should drink another 6 or 8 glasses a day in order to have some sort of improvement in your health. For that, there is virtually no basis at all. There’s no actual science behind the claim that six to eight glasses of water per day is necessary for good health, but nevertheless, the claim gets tossed around by the government, WhatsApp, the media, and just about anyone who fancies him/herself as a nutrition expert. 

The original “eight glasses” claim purportedly comes from a recommendation by the 1945 U.S. Food & nutrition Board, which stated that we should drink 2.5 liters of water every day for good health. The recommendation wasn’t based on any actual research. Unfortunately, in lieu of more concrete directions, this recommendation took hold in our culture. Add in the fact that nutrition science is complicated and poorly understood (even by experts!), and it’s clear why we can’t seem to shake the idea that more water equals better health.
For calculating the minimum amount of fluid per day, a formula based on body weight is recommended: 1500 ml is the minimum water intake with 15ml fluid per kg to be added for the actual weight minus 20 kg. This formula can be used for older adults who are normal weight, underweight, or overweight.
Some sources suggest taking half your body weight and aiming for that total in ounces; for example, a 200-pound person would need 100 ounces of water each day. However, this is just a rule of thumb—there’s no specific formula that works for every person. There are just too many variables that go into the equation, especially when you start adding water intake from solid foods. Your needs will depend on your body weight, local climate and activity level.

Every person’s water needs are unique, and as such, we need to rely on our own unique signals when deciding whether we’re properly hydrated. According to Mayo Clinic, there are a few easy ways to stay hydrated, no matter how much water your body needs:

  • Drink water or other liquids regularly, including with meals
  • Drink any time you feel thirsty (or hungry!)
  • If you’re exercising, drink extra before and after a workout
  • It should be easy enough to tell whether you’re hydrated.  Thirst, fatigue, and overtly yellow urine are signs of dehydration. Aim for a routine of daily water intake that matches the energy you expend.

Note that your daily “water intake” encompasses more than just the liquid you drink. Nearly every food we eat has water in it, and some (like fruits and vegetables are extremely water rich. Many of us end up getting much of our recommended liquid intake just from the meals we eat.  In short, you might be more hydrated than you think you are — even without downing a tall glass of water at every meal. It’s not important that you force yourself to chug water each day in hopes of meeting an arbitrary goal. What is important is that you listen to your body’s signals and adjust your intake until it matches your lifestyle.

About Vispi Kanga

Vispi Kanga was the principal scientist in global technology at Unilever and has more than 35 years experience in product development in dermatology and skin care formulations, working for multi-national companies in health and personal care industry. He has followed the evolution of the Health & Personal Care industry since the 70’s to it’s current stature as a $146 billion business in the United States.

His expertise has resulted in several patents in the development of new innovative products. He received his BS in Pharmacy from Ahmedabad India and did his postgraduation from Arnold & Marie Schwartz College of Pharmacy & Health Sciences (formerly known as Brooklyn College of Pharmacy).

Vispi has given numerous presentations in the area of skin care delivery systems and use of natural ingredients to the Personal Care Ingredients & Technology division of Health & Beauty America as well as other scientific organizations including Panacea, natural products expo India. He was the contributing editor of HAPPI magazine and also contributed articles and editorials in SpecialChem-The material selection platform. He was also an adjunct professor in the Graduate School of Natural Sciences at Fairleigh Dickinson University.

You can find all articles by Vispi Kanga on Parsi Khabar at this link: Vispi Speaks