How Much Water Should You Actually Drink?

You’ve heard of the saying to drink 8 glasses of water a day. But in reality, how accurate is this amount? And where did it come from? 

As with most things in nutrition, it all differs with each person. Guidelines from the Institute of Medicine and Dietary Reference Intakes suggest 2.7 liters of water daily for women and 3.7 liters for men. However, this is not a set in stone quantity, and the amount a person should drink depends on a variety of factors, including but not limited to:

Activity 

Whenever you exercise for an extended period of time, you lose a substantial amount of water; not only through sweat, but also through increased respiration. Always remember to bring water whenever engaging in physical activity.  

Medication

Diuretics, antihistamines, laxatives, etc. can cause additional water loss. Those on medications may need to drink more water.  

Age

Many older people use some form of medication in their daily lives. In addition, the kidneys, which are responsible for fluid regulation, become less effective with age, which can result in dehydration.

Pregnancy

Pregnant women support their babies with not only nutrients, but water. The body goes through numerous changes during pregnancy, including the production of amniotic fluid, increase in blood supply, and diarrhea/vomiting that may occur. Therefore it is important for those who are pregnant to stay hydrated.

Environment

Water needs may change with the seasons. During the summertime, you may need to up your water intake. 

So Where Did 8 Glasses Come From?

The 8 glasses of water myth goes back to a posting from the U.S. Food and Nutrition Board in 1945, stating that you should drink 2.5 liters of water a day. In reality, due to so many factors influencing hydration, having a universal standard for everyone doesn’t make much sense. For more personalized recommendations regarding water intake, consult a doctor or dietician.