Does exercising in the heat burn more calories? The short answer is yes; When you exercise and the weather is hot, your cardiovascular system has to work overtime to cool the body and maintain an even body temperature.
If you were to do the same exercise in a mild climate and a hot climate, the additional “cooling” efforts of your body in a warmer environment would result in a higher energy expenditure.
However, the extra calories would be very small and there are many other factors to take on board. Without additional heat, you can achieve better results and burn more calories, because you can train longer without harming your health and without additional stress on the body.
Let’s dive in and find out: Does exercising in the heat burn more calories? And if you want to avoid the heat altogether during your workout, check out our guide to the best home workout equipment (opens in new tab).
Does exercising in the heat burn more calories?
As mentioned above, your body has to work harder in the heat to cool down during exercise, so you can burn more calories, but the excess calories burned will have minimal impact on weight loss, says chartered physiotherapist Helen O’Leary.
“During exercise, your body temperature increases and supports the physical demands of the task. The body then regulates its temperature through sweating, so that heat can dissipate into the air. Add a hot climate to the process, and your body has to work even harder to cool itself down.”
Helen O’Leary is a UK-based Chartered Physiotherapist and Clinical Director of Complete Pilates (opens in new tab).
Interestingly, our bodies can actually adapt to hotter environments, requiring less exercise in sweaty temperatures. As noted by the CDC (opens in new tab)regular exposure to a hot environment improves sweat efficiency and increases blood flow to the skin, making it easier to regulate our temperature.
It doesn’t take long for these changes to take effect. A review published in Sports Medicine (opens in new tab) showed that people who trained in a hot environment for only 14 days could improve physiological adaptations.
O’Leary adds: “Like anything, we adapt incredibly quickly, so if you’re regularly using heat-based training methods, you’ll adapt, meaning the body won’t be working as hard and will need fewer calories to cool down. “
What happens to the body during exercise in hot temperatures?
Exercising in hot weather puts extra stress on your body. The exercise you do, the temperature and humidity all raise your core body temperature, and your body has to work harder to get rid of this extra heat.
“The main challenge for the cardiovascular system during exercise is to ensure adequate blood flow to the skin to effectively regulate temperature, as well as adequate blood flow to the muscles to support metabolism,” explains O’Leary.
When it’s hot, your body sends more blood to circulate through your skin, but that actually leaves less blood in your muscles. Add researchers (opens in new tab) It’s theorized that this may boost your anaerobic metabolism when your body converts glucose to lactate, meaning you’re more likely to burn stored fat instead of using oxygen for energy. However, not all recent research supports this.
Another thing your body does to cool itself is sweat: “The amount of sweat you sweat is related to the amount of blood flow to the skin…[but] How much we sweat varies, depending on the environment we live in, the clothes we wear, and the physical activity we do.
Sweating can definitely cause dehydration, especially if you’re not replacing the fluids you’re losing. As O’Leary said, it can create a bit of a tough environment.
“Dehydration due to sweat loss reduces blood volume and plasma tonicity [a cell’s ability to move water] – both reduce sweating and blood flow to the skin. This increases your body’s ability to cope with heat and the risk of serious dehydration.’
How to exercise in the heat?
Exercising in the heat increases your 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 more common in athletes. However, it can also happen when 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 higher the risk of dehydration or heat stroke. Look at when the sun is getting colder and try to schedule your exercise around that time. This usually means morning or evening.’
Is there a lot of humidity? If the answer is yes, that means there is more water in the air, making it harder for your body to lose heat.
It’s important to make sure you’re drinking water during exercise, but ensure you do so before and after exercise to replace fluids lost through increased sweating.
“If you live in a cold place and suddenly feel hot but want to continue exercising, just start slow and reduce your normal intensity level while your body adjusts. This can take up to two weeks, so be patient and listen to how you feel!”
How much water should you drink when exercising in the heat?
A lot of research has been done on this, and there is a very fine line between being “hyperhydrated” (having an excess of water in the body) and not being “hypohydrated”.
(being in a lack of water in the body.)
“The benefits of near-optimal hydration are that it helps you maintain your mood, recover from exercise, perform better, and conduct heat better.
“If you want to be really specific, you can calculate SL by calculating: pre-exercise body mass (kg) – post-exercise body mass (kg) + liquid Exercising (liters) – urine volume (in liters if available). Your sweat rate is sweat loss (litres) / duration of exercise,” says Helen.
What exercises should be done in high temperatures?
Helen says: “It depends partly on your ability and fitness level and there is no one size fits all. All exercises may be modified for hot weather; you just have to know the limit.
“On really hot days, you can try things like stand-up paddleboarding, kayaking, surfing or swimming. All of these will help keep you cool but also help you stay healthy and fit.” Staying hydrated is also important – don’t forget to grab one of the best water bottles. (opens in new tab) and drink from it regularly.
“If you’re new to exercise or have never exercised in the heat before, try gentle exercises like Tai Chi or walking. You can also do beginner Pilates, yoga or gym-based exercises with some body weight. Try to keep the program to the whole body rather than specific areas and allow your body to adapt. As mentioned above, it takes about two weeks.
“It’s important to know your fitness level. If you’ve never exercised before, it’s not a good idea to run in the heat of the sun. Instead, build up your tolerance gradually and remember that things take time to adjust!”