If you feel like your TikTok and Instagram feed has recently blown up with ads for rehydration tablets and mixes from trendy brands like Nuun, LMNT, or Liquid IV—you’re not alone. And it probably makes you wonder: Is chugging a plain old glass of water really the most efficient way to keep dehydration at bay? Especially if you’re hot and sweaty after a tough workout?
Before we get into that, though, it’s important to understand why your workout triggers the need to maximize your hydration. One big reason? Sweat. As your body temperature increases during exercise, your body responds by sweating, which then evaporates to cool you down. The longer you exercise, the more you sweat, and the more fluids and electrolytes—other components of sweat—you’ll need to replace.
You sweat more in hot and humid conditions, which makes hydration super important in warmer temperatures, but it’s also possible to become dehydrated after workouts in cooler weather, too, Riana R. Pryor, PhD, ATC, director of the Hydration, Exercise, and Thermoregulation (HEAT) Laboratory at the Center for Research and Education in Special Environments in the University of Buffalo, tells SELF. That’s partly because your thirst tends to be less pronounced when it’s cooler, which makes you not want to drink as much after a cold weather workout, she says.
So whether we’re talking about a workout in the blazing summer sun, a mild fall day, or even in the deep chill of winter, hydrating afterward is vital. But what’s the best way to do it? We chatted with a hydration expert and a registered dietitian/personal trainer who works with endurance athletes to break it all down. Below, everything you need to know about what contributes to proper hydration after exercising, signs you may be dehydrated, and some actionable ways you can make sure you’re maximizing your hydration after your next tough workout.
When thinking about hydration, you may focus solely on the water aspect. After all, you’re losing fluid, right? While that is true, water isn’t the only thing in your sweat that you need to replenish.
Your sweat is also made up of minerals called electrolytes, which include sodium, magnesium, and calcium chloride and bicarbonate, Holley Samuel, MEd, RDN, CPT, registered dietitian and founder of Fit Cookie Nutrition, tells SELF. These electrolytes are vital in your body, since they help balance the amount of water in your body and move nutrients into your cells and waste out of them, per the U.S. National Library of Medicine. Out of all of these electrolytes, sodium—aka salt—is the one lost in greatest concentrations when you sweat.
That means in order to remain optimally hydrated, you should take in a balance of water and electrolytes, says Samuel. It’s especially important to replace sodium, since not only is it lost the most in sweat, but it also plays the most important role in your body’s fluid balance.