Thirsty? How to drink?

Today we will be investigating Thirst as a measure of hydration status.

The weather lately has been great! Exercising is so much more fun when the sun is shining!

One thing becomes definitely essential when exercising outside though, Water. How much should we drink and when?

For those that do not work physically, there is no problem, just drink when you are thirsty (ad libitum).

 However, for those that work or exercise outside, does this method work? ( drinking at will)

Probably not.

Water is extremely important. It is essential to life.

Water contributes to 50-70% of our total body mass and is compartmentalised within both intracellular and extracellular spaces. Water is everywhere.

Typically, Euhydration, the state of normal level hydration, is maintained through normal physiological controls on a day to day basis. Unfortunately, under abnormal circumstances such as intense exercise or under extreme heat, homeostasis(balance) cannot be maintained efficiently.

This is when dehydration happens (the outcome being hypohydration). What are the consequences of dehydration? Risk of exertional heat illness, impaired thermoregulatory function, elevated cardiovascular strain, work or sports underperformance and more.

The main problem is, under intense exercise and hot conditions, our body tends to lose a lot more water than usual. Drinking only when thirsty doesn't work in this case because thirst is quenched before we become completely rehydrated. While the sensation of thirst works well at rest, it is much less sensitive during physical activity.

When we sweat and lose water excessively (over 2% body mass), we tend to get thirsty and we drink. However, during periods of high sweat rates, it has been reported that many under-consume fluid. Some drink less than half of the amount of fluids lost during exercise (Greenleaf et al.).

Why? Because thirst is alleviated before complete rehydration is achieved.

So, folks, when you exercise intensively especially under hot conditions, drink even when you are not thirsty! And drink a bit more than you normally would! We tend to underdrink when we exercise intensively!

Physio Summum Brossard