If you're doing long workouts like marathons, drinking when you're thirsty is safer than chugging water all the time — it helps avoid a dangerous low-sodium condition.

Telling athletes to drink as much as they can during long workouts might actually be causing more cases of dangerous low sodium, not preventing them.

Drinking too much fluid during long workouts can actually be dangerous — it can lead to a serious condition called low blood salt (hyponatremia), especially if you're gaining weight during a race because you're taking in more fluid than you're losing.

If endurance runners drink too much during long races, it can dilute their blood and cause dangerous low sodium levels — not just from losing salt, but from drinking too much. Cutting back on fluids in events over 4 hours could prevent this problem.

When you drink water instead of sugary drinks while resting or doing light exercise, your body burns more fat because sugar in drinks tells your body to stop burning fat.

Even if endurance runners take in a lot of salt, they can still develop low blood sodium if they drink too much water — it’s the overdrinking, not the salt intake, that’s the main problem.