Sports Nutrition Recommended Water Intake for Athletes During Exercise Calculating Your Need and Hydration Schedule By Elizabeth Quinn Elizabeth Quinn is an exercise physiologist, sports medicine writer, and fitness consultant for corporate wellness and rehabilitation clinics. Learn about our editorial process Elizabeth Quinn Medically reviewed by Medically reviewed by Richard Fogoros, MD on August 05, 2016 Richard N. Fogoros, MD, is a retired professor of medicine and board-certified internal medicine physician and cardiologist. He is Verywell's Senior Medical Advisor. Learn about our Review Board Richard Fogoros, MD Updated on November 22, 2020 Print Verywell / Alexandra Shytsman Anyone who has ever embarked on a routine fitness plan will have been advised to "stay well-hydrated" whenever exercising. But what does that actually mean? Does it mean that you need to drink as much fluid as you lose in sweat? And, if so, how much would that be? Or, would you simply use thirst as an indication of how much and when to drink? The short and simple answer is that the amount varies based on the individual needs of the athlete. It depends largely on the intensity and duration of the workout as well as other factors ranging from temperature, humidity, and altitude to age, gender, height, and weight. As generalized as this may seem, there are guidelines that can help determine your appropriate need, whether you are a thrice-weekly gym-goer or a high-performance athlete. Calculating Recommended Water Intake During and after exercise, you will need three cups of water for every pound lost. You would calculate this based on the intensity of activity for the day. At the low end would be a rest day in which you do little activity. At the high end would a moderate- to high-intensity training day, defined as an activity that raises your maximum heart rate (MHR) by 50% to 75%, or 75% or more, respectively. The amount of water needed for that day would be calculated as follows:Low end: Body weight (in pounds) x 0.5 = fluid ounces per dayHigh end: Body weight (in pounds) x 1.0 = fluid ounces per day For example, if you weigh 150 pounds, your daily water requirement would be between 75 and 150 fluid ounces. To determine your need in liters, you would then multiply that figure by 0.03 as follows: 75 fluid ounces per day x 0.03 = 2.25 liters per day150 fluid ounces per day x 0.03 = 4.5 liters per day This provides you the general parameters by which to maintain optimal hydration, neither drinking too little nor too much (which can be just as bad for you as dehydration). When to Hydrate Whether it is a training day or rest day, always start your morning by drinking an 8- to 12-ounce glass of water. On training days, you would need to hydrate before, during, and after exercise on the following schedule: Two hours before exercise, drink 16 to 24 ounces of water.20 to 30 minutes before exercise, drink another eight ounces.Just before exercise, weigh yourself to get a baseline weight.During exercise, drink eight ounces of water every 15 minutes.After exercise, immediately weigh yourself and drink 16 to 24 ounces of water for every pound of weight you've lost. At the end of your workout, you don't need to replace all of your fluids at once. Start with 8 ounces and continue to hydrate gradually over the next half hour. Longer, High-Intensity Workouts If exercising at a moderate to high intensity for more than 90 minutes, you will want to consume more than just water. This is especially true if you have saltier sweat. Commercially available sports drinks help replenish glycogen (stored energy) lost during exercise with easy-to-digest complex carbohydrates (like maltodextrin). As well, they replace the salts (electrolytes) lost in sweat. If exercising in extreme conditions for more than three hours, you need to take extra steps to replace electrolytes lost in sweat. These include minerals such as sodium, potassium, calcium, magnesium, and phosphate which your body needs to function normally. For longer, high-intensity workouts, choose a sports drink with 60 to 100 calories per 8-ounce serving and consume 8 to 10 ounces every 15 to 30 minutes. A complex sports drink, NUUN tablets, or electrolyte-rich foods can provide the calories and energy needed for continuous performance. Another option is coconut water, a natural source of carbs and electrolytes minus the added sugar or preservatives. You can even make your own sugar-free sports drink by mixing salt, freshly squeezed lemon juice, sweetener, and sugar-free flavorings with plain water. Was this page helpful? Thanks for your feedback! Get nutrition tips and advice to make healthy eating easier. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Kerksick, C.M., Wilborn, C.D., Roberts, M.D. et al. ISSN exercise & sports nutrition review update: research & recommendations. J Int Soc Sports Nutr 15, 38 (2018). doi:10.1186/s12970-018-0242-y Additional Reading Bushman, B. Exercise in the Heat and Adequate Hydration. ACSM Health Fitness J. 2013;17(4):4-7. DOI: 10.1249/FIT.0b013e318296bdda. Lopez, R. Exercise and Hydration: Individualizing Fluid Replacement Guidelines. Strength Conditioning J. 2012;34(4):49-54. DOI: 10.1519/SSC.0b013e318262e1d2. Shirreffs, S. Hydration in Sport and Exercise: Water, Sports Drinks and Other Drinks. Nutrition Bulletin. 2009;34(4):364-79. DOI: 10.1111/j.1467-3010.2009.01790.x.