Fluid intake and sports drinks: when does drinking make sense?

Joëlle Flück 8. July 2020

I’m sure we’ve all seen them - the runners with drinking bottles in their hands. I usually wonder how long the person has been running and whether the bottle is really necessary for the duration of this run. In this article, we will get to the bottom of this topic and consider the intake of fluids and carbohydrates in relation to the intensity and duration.

Presented by Swiss Sports Nutrition Society

In general, carbohydrates and fluids are not absolutely necessary for a training duration of up to 45 minutes. However, if the duration of the load is longer, for example 45 to 75 minutes, a few carbohydrates may make sense to sustain performance throughout the entire period. Athletes who have an extremely high sweat loss or who train in extreme heat can prevent a fluid deficit by drinking some fluids, such as water.

However, unless you are aiming for maximum performance capability, you don’t need any additional carbohydrates here either. Our carbohydrate reserves in the muscles should be sufficient – provided they are stocked up – to supply energy for up to 80 minutes. Furthermore, the body can also fall back on its fat reserves, unless the intensity is in a high or almost maximum zone.

If maximum performance is the main focus for loads of over 60 minutes, you should consider a carbohydrate intake of 30 to 60 g per hour in the form of glucose. In the case of an extremely long load duration (over 2 hours), the intake of fructose can also be used to increase the carbohydrate intake up to 90 g per hour. The amount of fluids you should drink each hour depends on the individual sweat rate. Feeling thirsty is a good indicator or drinking 4 to 8 dl/h is a good guideline.

Water or sports drink?

As already described, the duration and intensity of the load determine whether you should drink water or a sports drink. However, the athlete’s individual goal also needs to be assessed. When it comes to inducing weight loss or lipid metabolism training, the intake of carbohydrates can be a hindrance. However, if the aim is to achieve maximum performance or avoid tiring the body any further, the intake of carbohydrates via a sports drink can be considered appropriate. It is thus crucial to consider individual factors such as the goal, duration, intensity, sweating behaviour, and external environmental influences in order to make a targeted recommendation.


The intake of fluids and carbohydrates via a sports drink depends on various individual as well as external factors such as the duration and intensity of the load, the sweating behaviour, the overall goal (e.g. maximum performance, lipid metabolism training, weight reduction) and the environmental conditions (heat, altitude, cold). Feeling thirsty is a good indicator. Nevertheless, evaluating the individual sweat rate can help to determine the individual fluid intake. So, if you run for 30 to 45 minutes, a drinking bottle is superfluous. However, if you are planning to go for a long run or tackle a mountain pass on the racing bike for several hours, the intake of fluids and carbohydrates is an essential component that should be well planned.