About 1.5 liters from drinks
The German Nutrition Society (DGE) gives about 1.5 liters of water from drinks a day as a guide for adults. On top comes water from food, mainly fruit, vegetables and soups, and water formed by metabolism. Together that is about 2.5 liters. In heat, during exercise, with fever or diarrhea you need more.
HabitHelm uses this guide value as your base target. You can set your own water target in the coach.
On training days
During exercise you lose water through sweat. How much varies widely: the American College of Sports Medicine names sweat rates of about 0.3 to 2.4 liters per hour, depending on the person, load, clothing and weather (Sawka et al. 2007). As a rule of thumb, avoid losing more than 2 percent of body weight through water loss during a session, because performance drops.
HabitHelm estimates the extra need from sport, duration and, for outdoor workouts, the weather. A sweat test makes it more accurate: weigh yourself right before and after training. Weight loss plus what you drank gives your sweat loss, 1 kg is about 1 liter.
More is not always better. Drinking much more than you sweat during long endurance events risks a dangerous lack of sodium in the blood (hyponatremia). Drink to thirst and to your sweat loss, not as much as possible.
What counts as water?
Water, tea and other non-alcoholic drinks count towards your water target. In HabitHelm, alcoholic drinks do not. Alcohol also has 7 kcal per gram. Since 2024 the DGE no longer considers any amount of alcohol safe for health and advises avoiding it.
Mineral water contains different amounts of calcium, magnesium and sodium depending on the spring. If you choose your water in the settings, HabitHelm counts these minerals too.
Sources
- German, Austrian and Swiss Nutrition Societies: D-A-CH reference values for nutrient intake, water. Overview at vis.bayern.de
- Sawka MN, Burke LM, Eichner ER et al. (2007): American College of Sports Medicine position stand. Exercise and fluid replacement. Medicine & Science in Sports & Exercise 39(2):377–390. doi.org/10.1249/mss.0b013e31802ca597
- German Nutrition Society (2024): Position paper on alcohol, press release. dkfz.de