A Hot Metabolism on a Cool Day

Are there ANY benefits to exercising in cold weather?

Karen (Power) Hough
Feb 1 · 8 min read
Photo by Andyone on Unsplash

t’s winter, and nobody — NOBODY — does cocooning like me. The cold, the damp, the late sunrise and early darkness…why, it’s enough to keep me inside until May, wrapped in a blanket, wearing a sweater and legwarmers over my knees, with a hot cup of tea on my desk. Like I am right now.

I was hygge — which, in my interpretation, translates to “rocking fuzzy pants” — well before it was cool to be cosy.

Before continuing, let me make a bold admission: I am Canadian. I lived in Canada (the cold parts, where it gets down to -20 regularly, but “feels like” -35 with the wind) for 41 years, and am now living in London.

I love the weather here — even the rain can’t get me down.

I run a boot camp in a park. Nothing complex, not too much equipment to carry, but we meet once a week, rain, snow, or shine, and we work out. (This is a luxury; living in London, I’m not faced with the challenges of my Canadian existence, so I appreciate that the “ruggedness” of my London experience is relative.) On cold days (less than 5 degrees C), it’s a smaller draw; not many people come out.

On cold, wet days, still less, but — and this is highly scientific — we all feel AMAZING afterwards, and glad we came to exercise in the fresh air, breathing deeply, and catching a few rays of sun if we’re lucky.

There is a great deal of research out there on how exercise and cold weather affects our health, and a lot of it is inconclusive. I thought I’d take a look at the claims and/or myths from all those “Ten Reasons to Work Out in Cold Weather” clickbait articles that circulate every winter, and see if they really line up with the research.

“It boosts your metabolism.”

This claim showed up in almost every lay article. Let me debunk this one…sort of.

One of the main claims (that seems like common sense) is that, when you’re exercising in the cold, your body must work not only to exercise, but to stay warm; regulating your core temperature burns in the cold more calories and fat. And shivering has been repeatedly shown to burns lots of calories and increase metabolic rates.

However.

Exercise warms you up (duh). Although you might be shivering while waiting to start exercising, by the time you get going, the shivering is gone. (And for those who plan to kick start their weight loss routine by adding in some intentional shivering time, know that even a short bout of shivering impairs your performance and increases the onset of fatigue, meaning that you will not be able to train as well or as long.)

Interestingly, when exercising in warm weather, your body needs to expend far more energy to prevent overheating than it does in the cold to “stay warm”. Research shows that in the cold, your body doesn’t need to do much to not overheat (if you’re dressed properly in layers and removing them as you warm up), and can thus devote more resources to training and performance…which in turn can lead you to burn more calories and fat (but from the amazing training session, not from a so-called metabolic boost).

Finally, there is a well-hyped and growing body of research into the body’s ability to convert white (stored) fat into brown or beige fat when exposed to cold. Brown (and beige) adipose tissue (BAT) is good fat to have, as it’s metabolically active and burns calories, thus actually increasing your metabolism. It’s interesting science, worth a read if you’d like, and if it pans out to be true would be great news and a solid reason to exercise in the cold. Currently, though, the strongest terms they use is that cold weather “may” cause this conversion to a “small degree” in certain deposits of white fat in humans.

(If you’re a small rodent, however, it’s been proven in repeated, treadmill-in-the-cold studies. Good for you, small rodent! Have some celebratory cheese!)

(Note: if a mouse is using your computer, do they use a mouse? And are they insulted by this, or flattered?)

At the very least, the natural desire to cocoon in winter months (and eat delicious carbs) means that winter weight gain is a “thing” for most people. If exercising outside in the cold means you’re tricking your body out of its hibernating tendencies, then yes, you’ll be burning more fat and calories…

…than if you stayed inside on the couch. For six months.

“Exposure to Vitamin D improves your mood.”

This one has so many levels of interest and myth and fact.

First of all, vitamin D is great. It helps with absorption of calcium and phosphates, contributing to the health of our bones, teeth, and muscles. Most of the vitamin D we need (up to 90% of it) is absorbed from sunlight during the summer months.

In the UK (and anything above or below the 33rd parallel, north or south), there is not enough UVB in the sunlight in winter (October through early March for the northern hemisphere) for our bodies to produce our own vitamin D, and dietary supplements are recommended.

As well, despite many lay websites recommending exposure of ten or so minutes on face, arms or legs per day, I couldn’t find any specific (or research-based) recommendations, as skin colour, time of day and year, air pollution and latitude all affect how much an individual absorbs. The only consistent guideline? Wear sunscreen, of course.

But what about mood?

Seasonal Affective Disorder (SAD) is thought to be caused by lower levels of light exposure and less endorphins; symptoms include lethargy, sleepiness, and increased carbohydrate cravings. Recommended medical treatments are light therapy and drugs, with the NHS suggesting exposure to as much natural sunlight as possible, exercising regularly (which helps you produce your own endorphins) and managing your stress levels. Although research backs up the effectiveness of light-exposure treatments, whether or not the benefits are tied to vitamin D is still unclear. There is still no conclusive evidence that vitamin D alone is related to mood.

For further reading: this NIH summary of research shows a consistently positive correlation between exercise, exposure to sunlight (not necessarily vitamin D) and improvements in mood, and recommends it as a simple, cost-effective way to improve one’s mental well-being.

“Your immune system is strengthened.”

This claim was everywhere: blogs, magazine articles, research publications...without any reasonable scientific reference; it was almost as though it was supposed to be an accepted fact. Similarly, I suppose I wouldn’t need a reference for “the sky is blue”. But I digress.

These two made-for-the-public publications were the closest thing I could find to a proper endorsement. They (grudgingly) get credibility for being distributed by an Actual Health Department and a National Institute of Health.

The Pennsylvania Department of Health talks about the benefits of “playing outside” in cold air on immunity with several very plausible explanations: an escape from indoor germs and bacteria; development of a stronger autoimmune system; and a resistance to allergies. It finished strong: “studies have shown that children in rural areas or those who are active outside have the best overall health.”

This NIH page backs up my conviction that there is as yet no actual proof, just theories of how and why immune system function might be strengthened by exercise, without factoring in the element of cold.

Several articles vaguely reference CDC findings that I couldn’t find online. (This doesn’t mean that they’re not true, just that I couldn’t find them.) My feeling: there’s probably something in this. I mean, the sky is blue.

“It’s better cardio.”

The theory is that exercising in the cold increases the load on your cardiovascular system, because your heart needs to work harder to pump blood around a cold body, and thus gets stronger in response.

Most of the articles and experts seemed to feel that, since cardiovascular disease (and death by) is so prevalent, even if there’s the smallest chance that this is true, it’s worthwhile to try. However, others feel that this is risky for those who have heart disease, for, as the adage goes, “Whatever doesn’t kill me makes me stronger. Or kills me.”

Bottom line: consult your doctor.

“It strengthens different muscles.”

That it certainly can. Cold weather training can give you the inspiration and motivation to try new activities that aren’t possible inside or in the summer, using those well-trained muscle fibres in new ways. There’s downhill skiing! Skating! Cross-country skiing! Um… well, there must be more than that, but again, my cocoon beckons.

Trying new activities safely is an excellent way to cross-train, challenge new muscle groups, and invigorate a tired training plan.

…and the rest

The others in the Top Tens seem to be all remixes of the above, claiming the same things in different ways.

My own take?

All these claims and myths aside, exercise is good for you. Sunlight is good for you. Fresh air is good for you.

And, as I mentioned before, feeling warm enough to take off a layer or two during a hard, cold, wet workout feels AMAZING (at least when it’s over). And it makes the post-workout shower (and the subsequent climbing back into my cocoon) feel even better than usual.

Last January, three brave members of my running group did a good five miles in ankle-deep snow (again, we’re in London, not Canada, so it was impressive). We came through it laughing and glowing, our jackets tied around our waists. And the seven-mile run in the ice-cold downpour? We got to a point where the cold rain felt good on our faces, and the coffee afterwards was lovely. These experiences make the best stories; you never remember the boring workouts.

So, a beautiful winter’s day, with sparkling frost, crisp air, and a ray of sun? That’s worth getting out of that cocoon! So… what are you waiting for? (with your doctor’s permission) Get out there!


Want to try it out? If you don’t have an existing workout plan (by which I mean, My Dear Clients, Please Don’t Follow this Link Instead of Paying Me to Train You) the NHS has created this free Outdoor Gym 31-Day Plan.

Don’t forget to be safe: hydrate, dress in layers, wear a hat and gloves, and make sure you warm up and cool down properly.

And, of course, wear sunscreen.

Karen (Power) Hough is a writer and blogger with an Honours BSc. in Human Kinetics, who tries to Embrace Winter!TM every year, but she would really rather be inside with a book. Her part-time “superhero job” has been as a fitness instructor for over 20 years. She currently lives in London with her husband, three energetic kids and a codependent dog, and bores/impresses them all with stories about how she used to be a nutritionist, personal trainer and national-level fitness competitor.

Karen (Power) Hough

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Writer, blogger & total fitness nerd with an Honours BSc. in Human Kinetics. Personal blog: www.dammitkaren.com