How Often Should You Rehydrate During Exercise?

Replenishing fluids during exercise isn't an exact science

When you’ve got 26.2 miles of running, a 70.3-mile triathlon, or even just a long training workout ahead, arming yourself with a clear-cut plan for optimal performance provides a bit of nerve-calming comfort. You study race courses and plan training routes, calculate your cadence, diligently monitor your heart rate, and possibly even map a plan for replenishing fluids. 

It’s no news that hydration is an important part of optimal athletic performance (as well as general health and wellness), but according to Andy Blow, co-founder and Sports Scientist at Precision Hydration and a Red Bull High Performance partner, like your pace-per-mile plan or transition tactics, hydration doesn’t necessarily need to be a meticulously mapped-out part of your training or race strategy.

“There's no 'one size fits all' answer to how much and how often athletes should drink during events,” says Blow. “Firstly and most importantly, drink to thirst. The body is very adept at telling you when it needs fluid so learning to tune into its signals is the key to keeping your hydration levels just right.”

However, Blow warns that this doesn’t mean you should wait until you’re completely parched and then quickly down a large amount of fluids or drink more than you’ll need beforehand to “stay ahead” of your thirst, which will most likely leave you feeling too full and bloated.

 “It's all about learning (or re-learning) to listen to your instincts rather than setting out with any great pre-determined hydration plan to be followed to the letter,” says Blow. “Try it in training so you learn to read what your body is telling you, before you start to apply it in events,”

For recreational athletes who exercise over shorter periods of time, the same idea applies. The only difference is that you won’t need to drink as much because your perspiration amounts will be much smaller.

Blow also recommends that athletes pay attention to the temperature.

“As the temperature increases you'll need to consume more fluid to compensate for higher sweat losses,” he says. “But again, if you're listening to your body properly then you will probably find yourself increasing your fluid intake naturally so it shouldn't take too much conscious effort. Just make sure you've got adequate fluids available on hotter days, just in case you find that you need them.”

This is the first of three installments for our series on hydration featuring the expert insight of Andy Blow, co-founder and Sports Scientist at Precision Hydration and a Red Bull High Performance partner.

Part 2: Do You Need to Replenish Electrolytes After Exercise?
Part 3: How Much Water Should You Drink to Stay Hydrated?