Rehydrating the Body After Exercising
Updated: Sep 23
By Dylan Lowry MS, RD, LDN, CPT
When exercising hard, your muscles can generate 20 times more heat than when you are at rest. The human body dissipates that heat by sweating, and when that sweat evaporates, it cools the skin. If you did not sweat, your body would overheat and cause serious damage to your internal organs. This is a big reason why it’s important you don’t overexert yourself in very hot temperatures. It’s also a big reason why it’s important to rehydrate properly after exercising.
Measuring Sweat Loss & Proper Hydration
Sweat rate differs from person to person. Some people sweat a lot (a sign that your body is good at maintaining internal temperature) and some rarely sweat. Interestingly, females actually sweat more efficiently than men!
One way to understand how much sweat you lose — thereby knowing how to refuel — would be to weigh yourself nude before and after exercise to see how much weight you lost (sweat). Convert the amount in pounds that you lost to ounces to understand how much water you need to drink following your workout routine. For example, if you lost 1lb (16oz), that would mean you need to drink 16oz of water to properly rehydrate.
Can’t I Just Drink When I’m Thirsty?
Unfortunately, exercise blunts the thirst mechanism, so individuals partaking in physical activity (especially high intensity) will not have enough of a signal to properly refuel. Therefore, you should plan to drink before you are thirsty.
By the time your brain signals thirst, you may have lost 1% of your body weight! This is equivalent to 1.5lbs of sweat for a 150lb person, which requires your heart to beat an additional 3-5 times per minute. A 2% loss of body weight via sweat is the definition of dehydration, and this state will severely impair physical and mental performance.
Salt, Sweat & Staying Hydrated
Electrolytes are another big topic when summer workouts roll around. In your sweat, you are also losing sodium, potassium, calcium, and magnesium. Sodium is the biggest concern as individuals lose an average of 800mg of sodium in 2lbs of sweat. You would need to drink 33oz of Gatorade to obtain only 440mg of sodium, making many popular sports drinks an unwise choice for rehydration.
A better option would be an endurance sports drink (Infinite, Liquid IV, etc) and salty snacks like pretzels, V8 juice, olives, and pickles. Also, sprinkling salt on your meals will do the trick in the summer months, so don’t skimp on the salt when working out in the heat.
Nutrition HealthWorks Understands Hydration
A classic rule of thumb for water needs is dividing your body weight in half to find the number of ounces of water you should drink. So, for a 150lb individual that means 75oz of water per day. But if you are active and it’s summertime, those needs will increase significantly closer to 128oz or more. An easy way to increase your hydration without pounding water every second would be to make sure you are eating plenty of fruits, vegetables, and lean meats as these foods have very high water contents.
At Nutrition HealthWorks, our team understands that everyone’s body is different and requires a personalized nutrition plan to function and feel its best. Our team of registered dietitians will help develop a custom nutrition plan to ensure you’re meeting your wellness goals, staying properly hydrated, and managing your weight effectively. Contact us today to get started on your wellness journey!