During exercise, most of us hydrate by drinking as much as feels right in the moment. While drinking to satisfy your thirst is generally fine, UCLA’s Dr. Daniel Vigil recommends following a more precise regimen for peak athletic performance.
Proper hydration follows the Goldilocks principle: not too little, not too much, but just right.
Too little hydration, which can easily occur when we forget to drink or underestimate our needs in hot, dry conditions, can impair our workout performance.
"While a slight degree of dehydration is safe and won't affect athletic performance, a body water deficit of more than 2% of body weight can," says Vigil, associate clinical professor at the David Geffen School of Medicine at UCLA and team physician at UCLA.
On the other hand, over-hydration also poses risks – immediate and lingering.
"The immediate effects of drinking too much fluid can include a feeling of fullness, difficulty taking deep breaths as exercise intensity increases, and gastrointestinal problems like hiccups, nausea and vomiting," says Vigil.
Excessive over-hydration can result in the dilution of the body's electrolyte sodium, a condition known as hyponatremia, leading to headaches, confusion, and in the worst cases, seizures and brain swelling.
How to make sure we're drinking the right amount for peak performance, then?
To do so, Vigil suggests measuring your sweat rate (see our guide here), which will help you calculate how much fluid you need to replace.
That being said, if you're doing a shorter exercise or aren't too worried about optimizing performance, you probably don't need to sweat it.
"For events lasting less than an hour, hydration during exercise is usually not necessary," says Vigil. "For events lasting more than an hour, have access to fluids."
Tags: aerobic exercise, cardio, Dr Daniel Vigil, exercise, exercise tips, hydrate, hydration, hyponatremia, News & Insights, physical activity, sports, sports drinks, sports medicine, sweat, sweat rate, water