This question is one I’ve heard a few times before, so let’s answer it once and for all!
We’ve all been there – in the middle of an intense workout, or simply baking in the hot summer heat – and, like clockwork, the sweat glands swing into full action, doing their best to drench your clothes.
You might weigh yourself and notice that, after you’ve been sweating for a while, the reading on the scale has dropped. But what does that mean? Is it all water weight from lost fluids, or is some of it from you actually burning calories by simply sweating?
Sorry to disappoint you if you were looking for a different answer, but sweating alone has been conclusively shown to not burn calories. That doesn’t mean that you’re not burning calories while you’re working out – the sweat just doesn’t have anything to do with it.
If your workout buddy is sweating harder than you, that doesn’t even necessarily mean they are getting a better workout. Different people have varying levels of sweat glands, and their sensitivity to activation also varies. Some people just sweat more than others. Your drenched workout buddy could also just be in worse shape than you, causing their body to overheat more quickly.
Even though the mere act of sweating doesn’t do anything to help burn calories, that doesn’t mean there isn’t a correlation between sweat and burning calories.
For example, the recent hot yoga trend has taken advantage of the fact that your body burns more calories when you work out in a hotter environment. You just don’t utilize your energy as efficiently when it’s warmer, so your body has to work harder and your workouts become more effective. A side effect can certainly be increased perspiration – but those things are just frequently found together, the sweating itself isn’t what causes you to burn more calories.
When you do work out in a warmer environment, take caution not to overdo it. Stay hydrated, don’t work out when it’s too hot, and don’t push yourself too hard. The risk of heat stroke just isn’t worth it.
If you want to burn more calories just by changing the temperature around you, you’ll probably be more interested in keeping your environment colder.
Remember: Calories are energy. Energy is burned to maintain your body temperature, and the cooler your surroundings are, the more calories your body must burn in order to stay regulated.
Fun fact: The very definition of a calorie is the amount of energy required to warm one kilogram of water by one degree Celsius. Being warm just means your body doesn’t have to burn as many calories to maintain your core temperature. Being cooler, on the other hand, does burn more calories!