By Theresa Stahl, RD, LDN 

Q: I know it’s important to drink a lot of fluids, but do other sources count besides water?

It’s unclear where the recommendation for eight glasses of water originated, but it’s been around for a very long time and is generally recognized as a safe recommendation. 

Water recommendations may better be called fluid recommendations, and these include fluids from all sources, including soda, coffee, tea—as well as from food sources.  Many of the foods we eat contain 80 to 95 percent water. Remember, caffeine-containing beverages, including some sodas, coffee, tea, and energy drinks have a slight diuretic effect which increases fluid losses if ingested in large quantities.

Fluid needs vary depending on your weight, age, sex, calorie needs, level of fitness, activity level, health, and the environmental temperature and humidity.  The Adequate Intake (AI) for total water set by the Dietary Reference Intake Committee of the National Academy Sciences is 125 ounces (about15 cups) per day for men and 91 ounces (about 11 cups) per day for women.  Their report states that about 80 percent of the estimated total water intake is met by consuming water and beverages, while the other 20 percent is derived from foods.

The American College of Sports Medicine’s Roundtable on Hydration and Physical Activity states, “For an inactive person in temperate conditions, a daily intake of 33 to 67 ounces should be sufficient. For most moderately active people, daily water requirements usually range between 100 and 170 ounces.

According to Nancy Clark, MS, RD, author of Nancy Clark’s Sports Nutrition Guidebook, the simplest way to tell if you are getting enough water is to check the color and quantity of your urine. If your urine is dark and scanty, it is concentrated metabolic wastes and you need to drink more fluids.  Urine should be pale yellow. Some vitamin supplements can color the urine, though, so this is not always a reliable indicator. 

A very active person may want to weigh themselves before and after exercise.  For every pound lost, they should drink 16 ounces of water to replace fluids lost. Signs of dehydration include thirst, fatigue, headache, weakness, vague discomfort, loss of appetite, dry mouth, reduction in urine and difficulty concentrating.