Is water enough for exercise? When do you need electrolytes and carbohydrates?

Quick Facts:

• For workouts lasting up to 60 minutes, you don't necessarily need water.
• You should drink something if you're exercising for more than 60 minutes.
• You should start thinking about carbohydrates after about 60 minutes.
• You should replace sodium after 2 hours at the latest.
• Other electrolytes/minerals do not need to be replaced directly.

This classification is based on the scientific recommendations of the American College of Sports Medicine (ACSM) and the German Nutrition Society (DGE).

Drinking during sports: There are three levels

Whether water is sufficient or additional nutrients are needed depends on the duration and intensity. Scientific recommendations distinguish three levels.

Level 1: Up to 60 minutes

For short and less intense training sessions, you don't necessarily need to drink anything during exercise, if you start well-hydrated and drink something afterward. This is especially true for sessions under 40 minutes. Energy losses can be compensated for by existing carbohydrate stores.

Stage 2: 60 to 90 minutes

As your workout lasts longer, fluid loss through sweating increases. In most cases, water is sufficient in this situation. It's important that fluid loss doesn't exceed 2 percent of your body weight. Otherwise, it can lead to decreased performance and impaired cognitive function. Generally, you should drink according to your thirst to avoid consuming too much or too little fluid.

You usually don't need carbohydrates or electrolytes at this stage, as long as you're training moderately and it's not too hot. Interestingly, even small amounts of carbohydrates in your mouth can stimulate parts of the brain during exercise lasting as little as 45 minutes, thereby increasing well-being and performance.

Level 3: From 90 minutes

The situation changes after approximately 90 minutes of exertion. The German Nutrition Society (DGE) explicitly recommends drinks containing carbohydrates and sodium for longer periods of exercise to prevent performance losses. The American Society for Nutrition and Health (ASCM) recommends adding carbohydrates starting at 60 minutes. Sodium should be replenished after 120 minutes, or in cases of high sweat rates (over 1.2 liters per hour due to heat or high intensity), or if the sweat is particularly salty. According to the DGE and ACSM, you don't need any other electrolytes or minerals during training.

But why do we need carbohydrates and sodium?

Carbohydrates

• Over time, the body's own carbohydrate stores become depleted.
• Carbohydrates provide an important fuel for the brain, the central nervous system, and the muscles.
• Your performance during long or intense training sessions improves when you have sufficient carbohydrates available.
• When carbohydrate stores are depleted, fatigue symptoms occur, such as reduced performance, impaired concentration, and an increased perception of exertion.

Sodium

• 175–1,512 mg of sodium are lost per liter of sweat.
• Sodium is important for fluid balance and helps to retain water in the body.
• If you train for a long time and only drink water, this can in extreme cases lead to hyponatremia (too low sodium concentration in the blood).

Conclusion: Water is important, but not always enough.

The scientific recommendations can be summarized clearly. For very short sessions, water isn't strictly necessary. However, for sessions lasting an hour or more, you should definitely reach for your water bottle. After about 60 to 90 minutes of training, carbohydrates are beneficial for maintaining performance. For training sessions and competitions lasting longer than two hours, sodium should also be part of your hydration strategy. You generally don't need other electrolytes or vitamins during training. Understanding these three stages will significantly improve your hydration strategy and prevent both unnecessary supplements and actual performance issues.

 

 

Sources:

Thomas, D Travis et al. " American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance. " Medicine and science in sports and exercise vol. 48.3 (2016): 543-68. doi:10.1249/MSS.0000000000000852

Oberritter, H., et al. " Position of the working group sports nutrition of the German nutrition society (DGE): fluid replacement in sports ." Dtsch Z Sportmed 71 (2020): 178-184.