March 12, 2021

Hydration during cycling

We all know proper hydration is important for our health. But during exercise, this might be even more important. Mild dehydration (about 2% loss of bodyweight) can already impair performance and severe dehydration could have detrimental effects.

In order to keep up performance and prevent negative side effects of dehydration, we’ll need to consume sufficient amounts of fluids during the ride. However, this may sound easier than it actually is. Drinking to thirst is often not the best practice, since thirst is not always an accurate indicator of the degree of dehydration. Sensation of thirst is generally perceived after someone has already lost a considerable amount of sweat, which could already impair performance. Therefore, drinking with a hydration plan is preferred. Especially in hot conditions or during prolonged or high-intensity exercise.

In order to minimize the extent of dehydration, it is a good idea to start your ride well hydrated and consume fluids during your ride. How much you’ll need depends on the duration and intensity of your workout, the environment (temperature and humidity) and personal sweat rate (in these specific conditions). Ideally your fluid intake during exercise should match your sweat loss, in order to prevent excessive dehydration and changes in electrolyte balance as well as overdrinking (hyponatremia, which could be dangerous). However, sweat rate could vary significantly between individuals. Therefore, in order to create a proper hydration strategy, it is beneficial to measure your sweat rate under specific conditions.

How to bring this into practice?

Hydration before cycling

Aim for the consumption of 6 to 8 ml per kg body weight (generally this means roughly 500 ml of fluid) about two hours before your ride. Drink another 500 ml about 15 minutes before you take off.

Hydration during cycling

How much: try to drink as much as tolerable (comfortable) up to the rate of sweat loss.  If you do not know your sweat rate, generally it is advised to drink 500 up to 1000ml of fluids per hour. PS: there is a way to indicate your personal sweat rate relatively easy. In another blog we’ll explain how to do this.

When: try to drink in regular intervals (like every 15 to 20 minutes) instead of consuming a big amount of fluid at once.

What: adding some carbohydrates (hypotonic drink) and sodium to your drink can contribute to hydration, by increasing absorption and retention of fluids. However, by increasing carbohydrate intake to a large degree, absorption of fluids may be impaired. With a concentration of 4-8% (hypotonic or isotonic drink) the impairment in fluid absorption is acceptable. For more information on this read our article about sport drinks.

Hydration after cycling (rehydration)

How much: even when you consume fluids during your ride and start in a well hydrated state, some degree of dehydration after your training or race is still likely to occur. Drinking a fluid rate equal to your fluid deficit at the end of your ride is not enough to restore fluid balance. Therefore, aim to drink a volume of 125-150% of the post exercise fluid deficit. A rough indication of the amount of fluid deficit can be obtained by measuring bodyweight loss, in which 1 kg indicates a loss of 1 liter of fluid.

 

Why drink more than you sweat during cycling?

Your total sweat rate was 3 L during your ride. But you have managed to drink 2 L. The final deficit of hydration will be about 1 L (you are likely to measure a loss of 1kg body weight). Aim for drinking 1,5 L after your ride in the recovery period to ensure the fluid balance is restored within 6 hours.

What: especially in the case of extreme sweat loss during your ride, you also need to restore your electrolytes balance -particularly sodium- to make sure fluids are retained. High electrolyte sports drinks, or additionally consuming salty foods, may help.

Do you want to know what you can drink best and how to make it practical? With help from the EatMyRide app, you can create your own personal hydration strategy!