How Much Water Should I Drink?

The question of how much water to drink does not produce a quick and easy one-answer-fits all response. The answer will depend on many factors which will include temperature, humidity, gender, body weight, size, food intake and level of activity. Nevertheless the DRI committee sets guidelines of 2.7 liters a day for women and 3.7 liters a day for men. This amount does include food and beverage intake if you are worried about having to chug down that much. 

What Type of Water Should I Drink?

It really does not matter if the water you are drinking is tap or bottled water. The most important thing I think is making sure it’s clean and safe to drink. In the US, tap water must be by law potable (drinkable). The safety of tap water is regulated by the Environmental Protection Agency (EPA). On the other hand, bottled water is regulated by the Food and Drug Administration (FDA). You might already know that the bottled water industry is a multi-billion dollar industry. Bottled water comes in all “flavors” including “gluten free water”. I saw this statement on a bottled water label and a few years ago and chuckled at how ridiculous it was. But anyway, you can find flavors such as orange, mango, strawberry, cucumber, you name it. I normally go for the ordinary purified bottled water. Sorry, I can’t stand the awful taste of the water coming out of my tap. I know it’s clean but it is too hard for me. By hardness, I mean that it has a high mineral content. I prefer to buy bottled water and usually go for purified water instead of spring water which I think have taste issues as well.

Water is the best source of fluid but other fluid sources that we tend to get quite a bit of include coffee (and tea especially if you are British, I suppose), sugary drinks, carbonated beverages, and alcohol. I personally don’t drink coffee because of the addictive nature of caffeine but the verdict on coffee drinking appears to be mixed in the scientific literature with some health benefits coming from the phytochemicals it contains. Sugary drinks and carbonated beverages has been accused of raising the obesity problem in the US. That might be true considering the dump-load of sugar they contain. You are probably better off reducing intake of these beverages and looking for healthier options such as low-sugar natural juices…well….if you can afford it. As for alcoholic beverages, they do not provide hydration but accomplish just the opposite. Alcohol suppress antidiuretic hormone (ADH) in the kidney, increasing fluid loss and hence, your visits to the urinal.  

How Do I Make Sure that I get Enough Water Daily?

I think it’s fair to say that most of us wait until we are thirsty before we drink water. But, thirst is generally not a good indicator of when we should start rehydrating. We are normally dehydrated long before we feel the urge to drink. Consult the DRI to remind yourself of how much water you need daily. Remember that this is at least 3.7 liters a day for men and 2.7 liters a day for women. You can add to that if you are very active or working in an environment where you are sweating a lot. You can know if you are doing OK by checking the color or your urine as you go throughout the day. Light yellow is good, dark is bad. It means you are dehydrated.

Image result for pee color hydration
Urine color

For the fun of it you can weigh yourself before and after a period of heavy sweating such as working out in the gym or doing yard work in the summer. It will give you are good baseline of how much water you normally loose during these times and therefore how much water you need to get your body replenished. Avoid the habit of not drinking enough water. This leads to chronic dehydration which, along with other problems, can contribute hypertension. Adequate water intake will stabilize blood pressure to normal levels, while not getting enough will trigger vasoconstriction (construction of blood vessels) in order to restore blood pressure. If you are in a constant or frequent state of vasoconstriction, then high blood pressure will be a norm for you. But, in your attempt to keep hydrated, don’t over-drink since this disrupts electrolyte balance, raise blood pressure to unacceptable levels, and puts pressure on the kidneys. A blood pressure of 90/60 to 120/80 is considered normal. Remember that the top number is the systolic pressure and the bottom number is the diastolic pressure. Systolic pressure is the pressure that is felt in blood vessels when the heart contracts (tighten up to squeeze out blood) and diastolic pressure is the pressure felt in the blood vessels when the heart relaxes (not squeezing). 

Blood pressure chart

Reference: Thompson,&  J., Manore, M., Vaughan, L. (2020). The science of nutrition (5th ed.). New York. Pearson

Courtney Simons
Courtney Simons is a food science professor. He holds a BS degree in food science and a PhD in cereal science from North Dakota State University.
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