HRV, Exercise, and Hydration

To stay healthy, it’s important to replace the fluid we lose when we exercise, breathe, sweat or urinate. However, studies show that two-thirds of Americans do not drink enough water. With this in mind, how many of us realise the impact of adequate hydration on our recovery after exercise?


Hydration and Heart Rate Variability

The chart below was taken from a study on water intake and heart rate variability (HRV) after exercise (de Oliveira et al, 2011). It shows the positive influence water intake has on recovery HRV post exercise in comparison with a controlled group who did not hydrate after exercise.  Water intake immediately after exercise will also significantly reduce the chances of post-exercise cardiovascular events. These risks however are elevated if water is not consumed immediately after exercise.




Hydration and Sport

A high rate of fluid consumption during the first two hours of post-exercise rehydration does not only positively affect your HRV but is known to increase plasma volume significantly and decrease the risks of nausea and headaches. Additionally, athletes looking to achieve rapid and complete recovery from dehydration should drink 1.5L of fluid for each kilogram of body weight loss (Sawka & Burke, 2007).

At the other end of the scale, dehydration can negatively impact cognitive functions, physical performance, your immune system, body temperature and cardiac output. It’s clear that after a hard workout or event that it’s important to make sure that you have properly re-hydrated and in turn not only will your HRV improve but you will be ready for your next work out!

Whether you regularly exercise or not, the European Food Safety Authority recommends that women should drink about 1.6 litres of fluid and men should drink about 2.0 litres of fluid per day. That’s about eight glasses of 200ml each for a woman, and 10 glasses of 200ml each for a man.