There are many recommendations and formulas to determine how much water we should drink. So which one is right?
There actually is no recommended daily allowance (RDA) for water due to the extreme variability in individual metabolism, activity rates, and environmental conditions, according to the National Institutes of Health (NIH)(1).
Instead, the NIH suggests that the median water intake of adults 18-30 years old is an Adequate Intake (AI):
Males- 3.0 L/day (101 oz)
Females - 2.2 L/day (74 oz)
Although the AI is slightly higher, it is also appropriate to follow the age old advice of drinking 8 glasses of water per day (8 oz. glasses) if this is easier to remember. This applies for an average adult on a mild day who is not participating in moderate to intense exercise.
When to Increase Your Water Intake
However, on a hot day or following a workout, the number of ounces should be increased to avoid thirst and maintain hydration.
Athletes will need more water and a sports drink to maintain electrolytes based on weight loss during their activity.
A quick check:
clear/light yellow urine= hydrated
medium-dark yellow urine= drink more water
Why Drinking Water Is So Important
Other beverages besides water can contribute to the daily fluid intake, however, water is the best choice. Other beverages can add calories, sugar, fat, caffeine, and diuretic effects.
Water maintains body temperature and pH, metabolism, and the transportation of hormones, oxygen, and nutrients. When we become dehydrated, we risk feeling fatigued, getting a fever, and putting our cardiovascular systems in danger.
Can You Drink Too Much Water?
Yes. Drinking too much water can result in a condition called hyponatremia. (The "na" represents "Na" or sodium on the Periodic Table of Elements).
Hyponatremia occurs when the concentration of salt in your blood gets too low (2). This can happen from drinking too much water and causing your cells to swell. This swelling can cause many health problems, from mild to life-threatening.
How to Track Your Water Intake
If you are trying to improve your water intake this summer, especially if you're spending time outside in the heat or increasing your physical activity, you may want to track the number of ounces you drink.
You can do this with any measuring device such as a measuring cup or a water bottle that you know the volume of. You can also use a nutrition app like MyFitnessPal or FitBit to record the ounces of water you drink throughout the day.
After tracking for a week or two, you may be able to get into a routine of drinking water so you don't need to continue keeping records of how much water you drink.
(1) Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. (2005). Dietary reference intakes for water, potassium, sodium, chloride, and sulfate. Washington, D.C. The National Academies Press.
(2) Mayo Clinic. (2020). Hyponatremia. https://www.mayoclinic.org/diseases-conditions/hyponatremia/symptoms-causes/syc-20373711