A new study in Sports Medicine finds dehydration can zap your strength (by 2 percent), power (by 3 percent) and high-intensity endurance (by 10 percent) during a workout.
As a rule of thumb, drink 8 ounces (oz.) of water 30 minutes before you hit the gym to ensure your muscles are firing on all cylinders. Then drink 16 oz. within 30 minutes of finishing.
Deciding how much to sip in the middle of a sweat session is a little more subjective, but nutritional therapist Jo Scott-Dalgleish recommends aiming for 16 oz. during the course of a 1-hour workout.
Related: 10 Cardio Exercises That Burn More Calories than Running
After 90 minutes of moderate exercise, water is no longer enough. At this point, your glycogen stores are mere fumes, so you’ll need to start sipping electrolyte-rich sports drinks.
Managing your minerals is even more important if you’re an endurance athlete.
Drinking too much water without replacing electrolytes can cause a condition called hyponatremia, which may lead to seizures, organ failure, and even death. If you’re tackling long-distance runs, make sure you have a tried-and-tested hydration strategy in place.