4 Ways Winter Affects Your Physical Health

Winnter girl and snow fir tree.With winter all but officially upon us, we might already be feeling the season, maybe even planning warm weather vacations. I venture most of us have wondered if we’re not somehow healthier during the summer months. Is it just a mental vitality from the additional daylight hours and relative ease of outdoor time, or is there something more at work? Does our health really take a hit in winter? For those who enjoy this brand of trivia, there’s an actual field of study devoted to this called biometeorology. And with the minutely detailed research into epigenetic activity, we’re getting a fuller picture all the time of astonishing nuances as well as big picture shifts. To a Primal mind, it all makes sense. Humans evolved within a seasonal context—without any of the modern accommodations that would buffer climate or weather influences. Why would our bodies not have adapted with responsive wiring?

With the span of modern research—everything from massive epidemiological analysis to epigenetic science—we’re seeing both the finer nuances and the global patterns in environment-biology interaction. One recent study earlier this year, for example, revealed the activity of nearly a quarter of our genes varies depending on time of year—with seasonality cues that are remarkably geographically specific. The shifts influence our immune function as well as the composition of our blood and even fat.

I’ll admit this is exactly the kind of thing you could get me talking about for hours, but let’s keep things simple and look at a few of the most common and significant seasonal health patterns. It might just have you rethinking your annual exam routine—or at least its place on the calendar.

Your Cardiac Health and Risk

It’s no one’s imagination that we see more cardiac deaths during the winter months. The seasonal blood vessel narrowing may push those with arterial build-up, for example, over the edge in terms of blockage.

Oddly, it doesn’t seem to matter how hard winter hits your region. One study followed the incidence of cardiac-related deaths in seven U.S. locations (ranging from Los Angeles County to Massachusetts. Both total and cardiac death rates rose during winter months at roughly the same (26-36% compared to summer deaths) across all locations. Researchers often speculate that people move less in winter, even in warmer climates, and that this discrepancy could be a major contributing factor.

Yet, there may be other factors at work, particularly for those who live in colder climates. Blood viscosity (thickness) increases substantially in cooler temperatures. In one study, viscosity rose more than 26% when temperatures dropped from 98 degrees Fahrenheit to 72. The thicker our blood, the higher our risk for stroke and ischaemic heart disease.

Your Blood Pressure

In response to the lower temperatures of winter, blood vessels constrict, which raises your blood pressure and, particularly for those with higher measures to begin with, puts added stress on the heart and circulatory system. The rise in blood viscosity and decrease in blood flow rate naturally requires a corresponding increase in blood pressure to compensate.

For anyone who’s been diagnosed with high or borderline high blood pressure during the winter months, it’s important to take into account the seasonal shift. Get your levels tested throughout the year to get a more accurate picture. You may have what’s called “seasonal hypertension,” which research suggests is more common in certain people. Knowing that your numbers vary during the year will help you make a more informed decision about any given treatment your doc might recommend.

Your Lipid Profile

Researchers studied a group of men and women over a twelve month period, recording biomarker results for each season and collecting records for diet, activity and sun exposure during the year as well. Results showed that total cholesterol peaked in winter (as did HDL). (PDF)

Women showed the greater increase in total cholesterol at 5.4 mg/dL (a January peak) compared to 3.9 mg/dL (a December peak) for men. Those who had higher cholesterol levels to begin with showed the biggest seasonal rise. The researchers found no overall significant difference in dietary intake among the seasons and attributed a substantial portion of the increase to seasonal shifts in relative blood plasma volume.

As the researchers note, these differences have been demonstrated in other studies and suggest that seasonal shifts should be considered in medical testing. In other words, if you get your cholesterol tested in July and then in December, your numbers have a greater chance of looking “worse.” If you get them tested in December and then in July, they’re more likely to show “an improvement” when all that’s happened is natural seasonal shift. Obviously, these varying numbers would probably influence your doctor’s recommendations.

Your Body Fat

In a less expected twist, much has been made of the so-called “brown fat” that can convert fat into heat to warm the body. The more brown fat we have, it appears, the more adept we are at regulating our blood sugar, the more insulin sensitive we are and the better we are at burning our fat stores. Researchers have discovered how the body has an innate ability to convert typical “white” fat into “beige” fat when exposed to cold temperatures (a process hampered in obese people).

It may be one of our body’s innate bits of genius, but unfortunately the process may not be the completely seamless miracle you might think in our modern age. The activation of brown fat, it appears, causes more fat to be stored into the blood. Because vessels are constricted in cooler temps and cold can make atherosclerotic plaque less stable, the end result can be a greater risk for cardiac events, particularly in those with a history and propensity for atherosclerosis.

Our innate responses to our environments without question served our survival thousands of years ago. Today, they still serve our basic biology but not necessarily the ways modern life has skewed our daily behavior toward unhealthy diets and relative inactivity. Winter, I think few of you in the northern regions will doubt, imposes physiological stress on our bodies—the kinds of stresses we were designed to be able to incorporate and match with our own adaptations. The colder season, if you’re healthy, can make you that much healthier with some Primal behaviors (and vitamin D supplementation) Grok and his crew would’ve participated in. If the winter season is, instead, highlighting our current health limitations, we can consider it a call to live more, not less, in tune with the challenges our Primal roots were designed to anticipate.

Thanks for reading, everyone. Share your thoughts and questions in the comment board, and enjoy the end to your week.

Prefer listening to reading? Get an audio recording of this blog post, and subscribe to the Primal Blueprint Podcast on iTunes for instant access to all past, present and future episodes here.

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

If you'd like to add an avatar to all of your comments click here!

24 thoughts on “4 Ways Winter Affects Your Physical Health”

Leave a Reply

Your email address will not be published. Required fields are marked *

  1. Im an avid skier. I move much, much more in winter. Do you think this makes a difference?

  2. Lived in Cali for 10 years and loved the sun in the winter (I am from Minnesota). I have moved back to Minnesota and this will be my forth winter and while I think the day-to-day life in the cold is harder, the reward of getting out on an early Sunday morning when it is brisk cold and the sun is shinning is so magical. I have discovered the key to health in the winter is to get outside. We took up snowshoeing and I love it. Makes winter fun!

    I have noticed I do get sick more often living in Minnesota in the winter then I did when I was in California. Think the days of no sun drain me. But I met my beautiful wife in Minnesota so I will take it!

  3. Personally, I feel much healthier in the winter. I suffer from seasonal affective disorder with atypical patterns, often called summer depression. Yes, the warm weather and bright, long sun light makes me incredibly depressed. The relaxed calm of the cold winter, dimmer light helps me feel more relaxed. Not to mention all my old sports injuries, bad shoulder, bad neck, injured back, hurt less in the cold. I move more, eat less, and feel better. Plus my allergies abate when less is green. I love the winter.

  4. Personally, I feel a lot healthier in the winter. My body does not handle heat very well, and basically shuts down when it gets above 20° C (68° F). 14° C (57° F) is the ideal room temperature for me to sleep in, so I don’t get a lot of good sleep in the summer (most people don’t have air conditioning here in Canada). My days are spent lazing around because I just don’t have the energy to exercise (without an hours drive to the mountains, where it’s cooler), just getting up to use the bathroom feels like a chore on the hot days. I eat less healthy because firing up the stove just adds to the heat, so there’s way more sandwiches than there should be (plus I spend a lot of time as a guest at a friends cabin, where I don’t have control over what’s being cooked)

    In the winter, it’s like I come alive. I’m full of energy. I’m always cooking up healthy meals, walking the dog, getting my workout routine in, outdoor activities whenever I have time. It’s like I’m a whole new person.

    1. Absolutely! I love to split wood! We live in CT, and heat our house with a masonry heater, which makes clean and efficient use of the wood. Up until last year, I split with an axe, but last year my husband hunted up a 5 1/2 lb maul for me, which works great.
      You break a sweat really quickly splitting and carrying wood! It’s great exercise. And unlike shoveling, which I also enjoy, it is not dependent on the same sort of weather whims.

  5. So I had some genetic testing done to learn about my genealogy. Some of the data came back in the form of geographic locations (heat map) where my early ancestors originated.

    By the same thought that leads one to align diet and lifestyle with that of our paleolithic ancestors for the purpose of optimizing gene expression – could aligning my domicile in similar geographic conditions further improve my gene expression and overall health?

    For example – if I know that a large portion of my early ancestors lived in the deserts of the middle east or the mountains of the western Caucuses, should I be looking to relocate to similar conditions in the US? This is a rhetorical question of course. Just food for thought 🙂

    1. It doesn’t really matter because each region has its own fungi, bacteria and viruses living on plants and in the soil.
      My Dad is from the middle east my mother is Saami (Arctic Europe).
      We moved to southern Idaho thinking lots of sun and dry conditions would be good for me.
      Ended up with severe allergies, getting shots, still nothing works. The bacteria living in the soil here eats my flesh, my hands swell minutes after touching ANY soil in southern Idaho. I had allergy testing done and the Doc wouldn’t let me leave until I had an epi-pen on me, I am considered ‘critical’.

      It’s irony, really. I had 0 allergies living in Seattle, surrounded by water and a constant misty rain falling from the sky.
      I might look like my Dad, and have his temper, but apparently my immune system is that of my mother. I also inherited her guts, I need a diet high in protein/fat to be regular.

      1. I have a chiropracter who clears allergies so that you can live with what you are reacting to. My friend went to an acupuncturist to clear hers and they were BAD. It works on the same principles . A lot of the people I work with go and are cleared of their allergies even without going primal/paleo. Don’t know if you know a chiropracter that can do that but it’s worth considering – no needles, no pills, just testing by muscles and clearing through tapping on your back in specific places.

  6. Love, Love, Love winter in Wisconsin! I’d rather be out shoveling snow, walking, snow shoeing, riding my bike, playing with the dog (assuming he’ll come out of the garage-he is more of a laze by the roaring fire kinda guy) any day.

  7. Winter is bearable here in Oregon, but I am soooooo glad for the longer days and warmth of spring and summer and early fall. I have energy for EVERYTHING on those long “lazy hazy days of summm-ah” I get so much more done compared to winter. As I’ve said in the past, the benefit of growing older for me is that winter is “shorter” now.
    All I need is a home that is actually a big sauna for winter, aaaaaaaaahhhhhhhh.
    Oh, and the funding to pay for that kind of heat of course.

  8. I am definitely a warm weather girl…love to SUP, swim, etc. But the more active I stay in the winter, the better I feel. And I definitely supplement with some vitamin D in winter.

  9. Fascinating post today, Mark! In Chinese Medicine, we absolutely consider the season (and geography/climate) when prescribing medicinal herbs or eating/lifestyle guidance. We see adjusting one’s eating and lifestyle pattern to align with seasonal changes as part of staying well.

    Really appreciated this Western take on things–including the study findings. And, of course, it makes complete sense that our genes and bodies would shift depending on seasonal context. Strange, really, that conventional medicine doesn’t bring much attention to this.

    Also really like how you note the pull toward unhealthy (and non-primal) eating and lifestyle patterns during cold winter months (at least for lots of folks)…when, as you pointed out, it’s all the more important to live in alignment with our genes (and the season).

    1. That’s the amazing part. It DOES make sense. Trees lose their leaves, jackrabbits turn from grey to white, bears get fat and hibernate, dogs shed their summer coat and grow a thick winter coat. Why does modern medicine simply assume that the human body doesn’t go through any physiological changes as the seasons change, when every other species does?

      1. Modern medicine doesn’t assume that the human body goes through no physiologic changes as seasons change. You’ll note that the links in the article above (when they aren’t links to other Daily Apple articles) are links to modern medical journal articles. So, to say that modern medicine simply assumes the human body doesn’t go through any physiologic changes is not fair nor correct.

  10. I’m better at skiing than I am at surfing so I guess I’m a Winter person.

  11. I’m a snow bunny! In winter, I am delighted with XC skiing, snowshoeing and hiking with crampons. After a winter of sport, shoveling snow and splitting wood, I am in the best shape of the year. I wilt in the heat of the summer. Since I spend more time at home in winter, I can eat totally paleo and healthy. Winter is my vacation and creation time. I am keen to see what my blood pressure is in January.
    I imagine that some of Grok’s people were nomads who followed the sun. But there must have been plenty who wanted to or had to stay in the north in winter.

  12. It’s nice to read about so many people loving winter but I don’t think I’ll ever be able to like it. The only thing I like about winter is that it makes me feel that much more grateful for spring and summer. I don’t take it for granted!

    I miss the warm sun so much it’s crazy!

    1. Same here. I’ve had problems with seasonal affective disorder for years, but only when I lived in cold winter climes (the Midwest and England). In Hawaii and California – no problem. I’m back in the Midwest now, and nothing really seems to make much of a difference. A light therapy box left me horribly cranky and headachy. I already supplement with vitamin D. Exercise helps somewhat too, but it never gets me to the point where I feel as good as I do in the summer. I have reluctantly concluded that maybe I need to consider permanently relocating to someplace warm and sunny if I ever have the funds to afford the move.

  13. This article has me scratching my head. Except for the last item, conversion of white fat into beige fat (but with the accompanying danger of increased blood fat with arteriole constriction), all these winter effects seem to be negative. Why then did these physiological consequences to winter evolve? There must be more evolutionary upside. Are humans evolved to live in warm climates? Modern humans probably began migrating out of Africa about 100,000 years ago. Isn’t that enough time for some evolutionary adaptations to the cold to take place? Maybe we never developed these adaptations because the cold didn’t affect mortality up to reproductive age. Or maybe these adaptations helped babies and children survive, only to confer a disadvantage as humans lived into adulthood.

    Also, where do the benefits of cold therapy fit in? Mark has been advocating cold water immersion for a while now. Is it the time of the exposure to cold here that is the benefit?

    1. There’d usually be less to eat in the pre-agricultural period, approaching starvation towards the end of winter, so maybe having more fat carried in the blood helped combat the various side-effects of starvation, and low blood pressure is a common symptom of being under-nourished, so the seasonal rise would offset that. So these probably are adaptive responses.

  14. Found this article when googling “health effects of seasonal inactivity”. My husband and I are extremely active in the spring/summer/winter cycling up to 2,000-3,000 km per year in a very hilly area (built in interval training!) but for Dec/Jan/Feb/March we are moderately active at best. Mostly walking and/or snowshoeing when it’s not too cold in Atlantic Canada. Come spring, we can tell our cardio performance and leg strength is suffering but we get back to feeling fit and strong quickly. How does this yo-yo active lifestyle affect our long term health?