The body sweats to cool itself down as you’re blasting through a grueling workout. Without refilling the fluids you’re losing through sweat (and urine), you’ll get dehydrated.
“Sweating out 2% of your bodyweight will translate to negative affects on performance,” Clayton says. “You’ll notice the effects most during cardio. So if running a seven-minute mile is relatively easy for you, when you’re dehydrated, the body and heart will be working harder to achieve that goal.”
Proper hydration regulates body temperature and lubricates the joints; it can also help stave off constipation. Thirst is typically a delayed indicator that you’re dehydrated. But how can you tell for sure? Use the pee test.
“If your urine is clear or light yellow, like a lemonade, you’re in good status,” Clayton reveals. “When it’s yellow or bright yellow, that’s when dehydration is creeping in.”