The lifesaving “winter weather advisory” you won’t get on the evening news

According to the Farmer’s Almanac, we are in for yet another severe winter. This will be the third such winter in a row (providing me with some additional justification for moving back to Florida from New England several years ago). As some Yankee farmers themselves might say, “That global warmin’ sure’s a bitch, e-yah?” But Yankee farmers certainly know a few things about winter weather.

So do doctors.

Part of medical lore is that there are more heart attacks during winter. It was presumed these heart attacks occurred because men who don’t (typically) exercise regularly are suddenly out in the cold, strenuously and furiously shoveling tons of snow to clear their driveways so they can get to work (or to that NFL playoff game).

The classic causes of having an acute heart attack are exercise, emotions, and eating.  Franticly hurling snow meets two out of three of those criteria, combined with the potential effects of metabolic stress caused by the cold air. (Of course, it wasn’t always like that when it comes to shoveling snow. In fact, before the automobile became the “go-to” mode of transportation over the last century, snow and ice actually made it easier for farmers and other workers to get around outdoors by working with nature. They had sleds and sleighs to smoothly ride over the snowpack, and ice made it possible to ride over the frozen, flat, smooth surfaces of ponds, lakes and some rivers, instead of having to go all the way around them on bumpy roads.  Thus, Robert Frost could write a poem about stopping by the woods in the snow, with his horse-drawn sleigh, on the darkest evening of the year—the winter solstice, December 21- 22.)

There’s also speculation that blood may have a greater tendency to clot during cold weather. And of course, clots in the blood vessels that supply the heart and brain can cause heart attacks and strokes.

But while these theories make sense logically, there hasn’t been scientific research to prove them. Until now, that is.

In fact, three different teams of researchers recently decided to see if this winter-weather lore is really true. Their findings were striking — and offer some important insights that could very well save your life this winter.

When the temperature drops, heart attacks and strokes rise

Taiwanese researchers examined data from nearly 290,000 people with atrial fibrillation, a condition in which the atrium chamber of the heart doesn’t contract effectively. And that can cause blood to pool in the heart, potentially forming blood clots that can travel to the brain and boost your risk of stroke.

The researchers found that over a three-year period, about 35,000 of the study participants had a stroke.1 And stroke risk was 19 percent higher in winter than summer. It didn’t even have to be a particularly cold winter. The researchers found that the chances of people with atrial fibrillation having a stroke were significantly higher when the average lower temperature was even rather mild (anything below 68 degrees)

But colder weather also comes with some significant risks. According to another new study, freezing temperatures increase heart attack risk.2

Researchers checked databases in Winnipeg, Canada—one of the coldest large cities in the world—and discovered there were 1,816 severe heart attacks over a six-year period.

And when the mercury plummeted,  heart attacks soared. In fact, there were 16 percent more of the severest form of heart attacks (ST-elevation myocardial infarction, or STEMI) in Winnipeg residents when the temperature went below 32 degrees (freezing).

Finally, another new study found that the weather (and air pollution) may affect how long it will take to recuperate—and even your chances of survival—if you do have a heart attack.3

In heavily industrial Silesia, Poland, researchers collected data on 2,388 people who had heart attacks between 2006 and 2012. They discovered that within the first month after a heart attack, people were more likely to die on days when it was cold, sunny, and less windy.

Why? No one knows for sure, but the researchers suggested that wind blows away outdoor pollutants that may irritate the lungs and heart. And cold temperatures result in more home heating and combustion products, which generate more indoor pollutants.

How to keep your heart healthy when the snow falls

All told, evidence does show that colder weather causes more heart attacks and strokes. And it may even increase the risk of dying from a heart attack. These new studies suggest that colder climate is a neglected health issue that deserves more consideration.

But you can dramatically decrease your risk of a heart attack or stroke year round with some simple measures. In fact, exactly two years ago in the Daily Dispatch (12/5/13), I outlined six steps for protecting your heart from cardiovascular disease. You can review them by visiting my website, and entering “Six surprisingly simple steps for combatting cardiovascular disease” into the Search option at the top right-hand corner of the page.

In the meantime, my accountant in Florida gave me the most convincing and lengthy argument I have ever heard as to why moving to Florida is going to result in slower aging and greater longevity.  As you know, I have always found accountants and actuaries to have some of the best information on mortality and longevity because, after all, that’s where the money is.  And biostatisticians can’t manipulate mortality data the way they do clinical outcomes on drugs, for example.

Also, knowing about the amazing benefits of sunshine and vitamin D for health, I am tempted to consider that possibility as well to help account for the health benefits of warmer climates and more sunshine.

As I wrote in a January 2014 Daily Dispatch (“Key nutrient improves your chances of surviving a heart attack or stroke”), people with low levels of vitamin D in their blood have a 27 percent higher risk of having a heart attack or stroke. And a whopping 62 percent more chance of dying.

So no matter where you are over the holidays and this winter, make sure to take 10,000 IU vitamin D daily.


1”The relationship between cold temperature and risk of ischemic stroke in patients with atrial fibrillation.” Eur Heart J (2015) 36 (suppl 1).

2“How cold is too cold: the effect of seasonal temperature variation on risk of STEMI.” Eur Heart J (2015) 36 (suppl 1).

2“The relationship between the environmental factors and severity of clinical status and short-term prognosis for the patients with non-ST elevation acute coronary syndromes.” Eur Heart J (2015) 36 (suppl 1).