Brrr! It’s cold out there—but bundling up and braving the chill to exercise comes with its perks. Because your body is working harder to stay warm, you’re burning more calories than you would on a mild day.
Wondering how cold cranks up the calorie burn? Your body thrives on consistency—specifically, a core temperature of 98.6°F. When you’re exposed to the cold, your body’s built-in survival mechanisms kick into gear to keep you safe, explains Gary Brecka, a human biologist and longevity expert.
There are two primary ways the body does this. “Shivering thermogenesis is the obvious one. These are tiny, involuntary muscle contractions that generate heat fast,” says Brecka. But there’s a behind-the-scenes player, too: Non-shivering thermogenesis. This process taps into brown fat, a type of metabolically active fat.
“Brown fat isn’t the type of fat you see, but you feel its effects. It burns energy to create heat and raise your body temperature, essentially acting like a miniature furnace,” says Jeremy Alland, MD, a sports medicine physician at Midwest Orthopaedics at RUSH.
So, how cold is cold enough?
While experts confirm that cold weather does indeed boost calorie burn, the research isn’t nearly as extensive as what we know about heat. One of the reasons this area is so tricky to measure? Temperature alone doesn’t tell the full story. “A calm 20°F day can feel warmer than a windy 30°F day,” explains Dr. Alland. “Wind chill, sun exposure, clothing, terrain, and elevation are all factors that influence calorie burn.”
Another consideration is that even in identical conditions, your calorie burn won’t be exactly the same as someone else. “Body composition plays a big role. People with more muscle mass generally burn more calories than those with less,” says Eric Rakofsky, a celebrity fitness trainer.
Clothing matters, too. Since insulation reduces how hard your body has to work to stay warm, you’ll generally burn fewer calories with more layers on.
That said, a limited 2024 meta-analysis found that exposure to temperatures below 60 to 66°F prompts your body to start burning more stored fat for energy, with the average temp being 62°F. The range of 59 to 66°F is commonly used in research so the sweet spot seems to be somewhere in there for calorie burn without too much discomfort. Temperatures like these activate non-shivering thermogenesis without triggering uncomfortable shivering, according to Brecka.
Will an air-conditioned workout class give the same effect?
Not exactly, says Dr. Alland. “A super air-conditioned class isn’t the same as being outside in cold, windy weather,” he explains. “Air conditioning mainly removes humidity—it doesn’t create the same physiological demand.”
Brecka adds that there’s a reason we talk about “feels like” temperatures. Factors like outdoor wind chill can make 60ºF outdoors feel colder than 60ºF indoors. “Outdoor exercise at 60°F is likely to cause a greater thermogenic response than 60ºF indoors due to wind and radiant cooling,” says Brecka. “The ‘feel’ of cold matters. If your skin doesn’t feel cold, your brown fat probably isn’t being maximally activated.”
Still, movement is movement—it’s all beneficial, even if there isn’t a huge added calorie burn in air-conditioned workouts.
What to wear (and not wear)
When you’re getting dressed for cold-weather exercise, your base layer is most important. Ideally, this layer wicks moisture away from your body. Translation: Cotton is not your friend, says Amy Goblirsch, RDN, the founder of The Running Dietitian. “First, put on a moisture-wicking layer, and then you can add a fleece or wool. Your outside shell should be a waterproof or windproof jacket,” she says. For exposed skin, Goblirsch recommends a thin layer of Vaseline or Aquaphor on your face to protect against wind and cold.
Also, pay special attention to your hands, feet, and head, since these areas lose heat faster and are more vulnerable to frostbite than your chest or arms. Dr. Alland notes that heated vests or gloves may decrease thermogenesis to a certain extent, but whether that’s a drawback or a plus depends on your goals, such as prioritizing comfort versus maximizing calorie burn.
Winter workout ideas
Looking for inspiration to head outside? Here are some activity ideas from the experts:
- Walking or hiking
- Running
- Pickleball
- Skiing
- Snowboarding
- Jumping rope (in a spot that’s not icy!)
- Ice skating
- Playing in the snow with your kids
Whatever you choose to do, don’t skip your warm-up. “Cold muscles are tighter and more prone to injury,” says Dr. Alland.
Before you go outside, Rakofsky recommends doing a dynamic warm-up indoors—think jumping jacks, shuffles, or light mobility work. “Movement beats static stretching,” says Rakofsky. “The cold causes changes in blood flow, which can make your muscles feel stiff.”
Also, remember that the cold requires acclimation, just like the heat. “If you’re not used to exercising in the cold, you need to build up gradually to stay safe,” says Dr. Alland. “Start with more layers and shorter exposure. Over weeks or months, you can reduce clothing and increase your time in the cold.”
The bottom line
While outdoor winter workouts won’t magically melt fat, the cold does add a subtle metabolic edge along with the excitement of doing something you can’t do during other times of the year. And sometimes, that’s just the motivation you need to lace up and head out the door.
