There is a lot of conflicting information online regarding the right amount of water a person should be drinking every day. We have looked into medical literature and research for you to settle this question once and for all.
How much water do you lose a day
Human body loses about 1.05 L- 3.1 L of water per day under normal weather conditions without exercise and with a minimal water loss from sweating. The amount of water loss can be higher when exercising and with warmer ambient temperatures. Also, the bigger the body, the more water is lost throughout the day.
How much water do you lose a day when exercising, including hot weather
Exercising in hot temperatures leads to increased water loss through sweating. Typically, the hotter it is and the higher the exercise intensity, the more water is lost through sweating. The water loss through sweating can increase from an additional 0.7 L per hour in females exercising in temperate conditions to 1.1 L per hour when exercising in warm conditions. Males can experience sweating rates of 1 L per hour in temperate conditions, and more than 2 L per hour in hot conditions.
How much water should you drink a day when you are not exercising
The amount of water you should drink to prevent negative consequences of dehydration is called the adequate intake. The adequate intake of water comes from drinking water, beverages like coffee and juice, and eating food.
It is recommended to replace the lost water with 2.7 L of water for women ages 19-70+ and 3.7 L for men ages 19-70+ through a combination of drinking and eating. Water from drinking liquids should be in the amount of 3 L (101 fluid oz or ~13 cups) for men, and 2.2 L (74 fluid oz or ~9 cups) for women.
How much water should you drink when exercising, including hot weather
The extra amount of water that is lost when exercising typically comes from sweating. As a rule of thumb, the amount of water you should replenish your body with after exercise equals the amount of water you lost through sweating. It is fairly easy to find out how much water you lost through sweating by weighing yourself before and after exercising. The difference in weight will correspond to how much water you should drink to ensure proper hydration.
If you’re looking to build a consistent, feel-good fitness routine that supports your wellness goals- including staying properly hydrated- join our Free Fitness Program for Women! It’s designed to help you ease into exercise with fun, empowering workouts and simple wellness tips tailored for all fitness levels. You’ll get guidance on hydration, recovery, and how to fuel your body right.
Click here to join the free program now and start your journey toward a healthier, stronger you- inside and out.
Sources
Fit.Well.Thrive. articles are written by credentialed fitness, health, and wellness experts, who were professionally trained as part of their education to assess the quality and relevance of medical literature. Our authors only use credible, up-to-date, and evidence-based sources to ensure accuracy of our content.
- Dietary reference intake for water, potassium, sodium, chloride, and sulfate. U.S. National Academies of Science, Engineering, and Medicine. https://nap.nationalacademies.org/read/10925/chapter/6#74. 2005. Accessed April 15, 2025.
- Powers SK, Howley ET. Chapter 23: Nutrition, body composition, and performance. In: Powers SK, Howley ET, eds. Exercise Physiology: Theory and Application to Fitness and Performance. 10th ed. New York, NY: McGraw-Hill Education; 2018: pages 535-539.
