Does exercising in the heat burn more calories? The short answer is yes; When you train and it’s hot, your cardiovascular system has to go into overdrive to cool down the body and maintain a stable body temperature.
If you were to do the exact same exercise in a temperate climate and in a hot climate, the extra efforts of “cooling down” your body in the warmer environment would likely lead to higher energy expenditure.
However, the extra calories would be quite minimal and there are many other factors to consider. Without the additional heat, you would be able to perform better and burn more calories as you could train for longer without any health risks or added stress to your body.
Let’s dig deeper and find out: does exercising in the heat burn more calories? And if you prefer to avoid the heat altogether when training, check out our guide to best home workout equipment (opens in a new tab).
Does exercising in the heat burn more calories?
As described above, your body has to work harder in the heat to cool down during exercise, so you might burn more calories, but the extra calories burned will have minimal impact on weight loss, says exercise physical therapist Helen O ‘Leary.
“During exercise, your body temperature rises to support the physical demands of the task. The body then regulates its temperature by sweating so that the heat can be dissipated into the air. Add hot weather to this process, and your body has to work even harder to bring its temperature down.”
Helen O’Leary is a UK based Registered Physiotherapist and Clinical Director of full pilates (opens in a new tab).
Interestingly, our bodies can adapt to warmer environments, making exercising in sweaty temperatures feel less taxing. As he outlines Centers for Disease Control and Prevention (opens in a new tab)Regular exposure to hot environments can improve sweat efficiency and increase blood flow to the skin, making it easier to regulate temperature.
These changes also don’t take long to kick in. A review published in Sports medicine (opens in a new tab) showed that people who train in warmer environments for just 14 days could experience improved physiological adaptations.
Adds O’Leary: “As with anything, we are incredibly quick to adapt, so if you regularly use heat-based training techniques, you’ll acclimatize and therefore the body won’t work as hard and will need fewer calories to refresh. ”
What happens to the body during exercise in high temperatures?
Exercising in hot weather will put extra pressure on your body. Your exercise, air temperature, and humidity can all increase your core body temperature, and your body needs to work hard to get rid of this extra heat.
“During exercise, the cardiovascular system’s main challenge is to provide sufficient blood flow to the skin for effective temperature regulation, but also to provide sufficient blood flow to the muscles to support metabolism,” explains O’Leary.
When it’s hot, your body will send more blood to circulate through your skin, but this will actually leave less blood in your muscles. Some researchers (opens in a new tab) have theorized that this could increase your anaerobic metabolism, which is when your body turns glucose into lactate, so you could be burning stored fat instead of using oxygen for energy. But not all of the latest research supports this.
The other thing your body will do to keep you cool is produce sweat: “The amount of sweat is related to the amount of blood flow to the skin…[but] how much we sweat is variable and also depends on the environment we are in, the clothes we wear and the physical activity we are doing.
Sweating, of course, can lead to dehydration, especially if you’re not replacing the fluid you’re losing. This can set off a vicious cycle, according to O’Leary.
“Dehydration from sweat loss results in reduced blood volume and plasma tonicity. [a cell’s ability to move water] – both reduce sweat production and blood flow to the skin. Because of this, your body’s ability to get rid of heat is reduced and your risk of serious dehydration will increase.”
How should you exercise in the heat?
Exercising in the heat can increase the risk of heat exhaustion: this is when the body overheats in response to external factors, such as temperature. It can happen to anyone and is common in athletes. However, it can also happen when you are sitting in a hot car.
“You can still exercise in hot weather, but there are a few things to keep in mind,” says O’Leary. “The higher the temperature, the greater the risk of dehydration or heat stroke. See when the day is getting cooler and try to schedule your exercise for that time. This usually means earlier mornings or later evenings.”
There is a lot of humidity? If the answer is yes, it means that there is more water in the air, which will make it harder for your body to lose heat.
Making sure you drink water while you exercise is key, but also be sure to do so before and after exercise to replenish fluid you’ve lost due to increased sweating.
“If you live somewhere cold and it’s suddenly hot but you want to keep exercising, just start slowly and reduce your normal intensity levels while your body adjusts. It can take up to two weeks for this to happen, so be patient with yourself and listen to how you feel.”
How much water should you drink in the heat when exercising?
Much research has been done on this, and there is a fine line between being “hyperhydrated” (having too much water in the body) and “hypohydrated.”
(being in a body water deficit.)
“The benefits of having near-optimal hydration is that it helps you maintain your mood, recover from exercise, perform well, and have good heat transfer.
“If you want to get really specific, you can calculate your sweat loss (SL) by calculating: pre-exercise body mass (kg) – post-exercise body mass (kg) + volume of liquid consumed during exercise (litres) – volume of urine (if any in litres). Your sweat rate is then sweat loss (litres)/exercise duration,” says Helen.
What are some of the best exercises to do in high temperatures?
Helen says: “This partly depends on your ability and fitness level and there is no one size fits all. All exercises can be modified for hot weather; you just have to know your limits.
“On really hot days, you can try things like stand-up paddleboarding, kayaking, surfing, or swimming. All of this helps keep you cool, but it will also help you stay fit and healthy.” Staying hydrated is also key – remember to choose one of the best water bottles (opens in a new tab) and drink from it regularly.
“If you’re a novice athlete or have never exercised in the heat before, try gentler exercises like Tai Chi or walking. You can also do some beginner Pilates, yoga, or gymnastics exercises with bodyweight. Try to keep the program for the whole body rather than specific areas and let your body adjust. As we said, it takes about two weeks for this to happen.
“Knowing your level of exercise is very important. If you’ve never exercised before, going for a run in the midday sun is not a good idea. Instead, build your tolerance slowly and remember that things take time to adjust.”
