The amount of water one should drink daily varies based on factors like age, sex, activity level, climate, and health status. General guidelines from health authorities are:
- For healthy adult men: about 15.5 cups (3.7 liters) of fluids per day.
- For healthy adult women: about 11.5 cups (2.7 liters) of fluids per day.
These recommendations include all fluids consumed, including water, other beverages, and water contained in food
. Other considerations affecting water needs include:
- Living in hot, humid, or high-altitude environments increases water requirements.
- Higher physical activity or exercise increases water loss and thus intake needs.
- Diets high in salt, sugar, or caffeine may increase fluid needs.
- Health conditions like fever, infections, diabetes, or medication use can increase water requirements.
- Pregnant or breastfeeding women need more fluids, around 10 cups (2.4 liters) for pregnancy and up to 13 cups (3.1 liters) for breastfeeding
Some guidelines also suggest aiming for about 6 to 8 cups (1.5 to 2 liters) of fluids daily for adults in temperate climates, but this is a more general recommendation
. A practical way to estimate personal water needs is to drink according to thirst and adjust based on activity, environment, and health. Another method is to drink about half your body weight in ounces of water daily (e.g., a 200-pound person drinks about 100 ounces)
. In summary, while the commonly cited "8 glasses a day" is a simple rule, individual needs vary widely. The U.S. National Academies suggest about 3.7 liters for men and 2.7 liters for women daily, including all fluids and food moisture
