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Stress hormones, carbohydrates and immune system

Stress hormones, carbohydrates and immune system

Did you know that prolonged high intensity training can have an impact on the immune system? This can put the person at a much greater risk for developing a respiratory tract infection. There are several strategies to protect your immune system. The first is actually much simpler than you think: ensuring adequate carbohydrate intake.

What do the studies say?

The most recent studies show that the consumption of carbohydrates during exercise decreases the secretion of cortisol and norepinephrine after intense and prolonged exercise, two hormones that weaken the immune system. Since exercise is stressful on the body, it responds to it by secreting hormones, creating an immune response. The higher the intensity and the longer the exercise, the greater the response.

A study in elite cyclists showed that cortisol levels remained elevated in the blood two hours after intense and prolonged exertion in the group who drank only water. In contrast, among cyclists who consumed energy drinks, there was very little variation in cortisol levels.

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It is recommended to take 30 to 60g of carbohydrates per hour of exercise in the form of an energy drink, bars or gels to avoid a too large drop in blood sugar.

Finally, other factors can play a role in the health of our immune system by affecting the health of an athlete: poor diet, lack of sleep and rest between workouts, and psychological stress.

That being said, don’t neglect your exercise diet, just like you don’t neglect your workout!

Your body and your physical performance will thank you.


Nieman DC, 2006, Influence of carbohydrate on immune function following 2 h cycling, Res Sports Med. 2006 Jul-Sep; 14 (3): 225-37.

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