Baby, it’s cold outside – and risky to your heart

Going out in cold weather, you might get a chill. If you’re older, obese, diabetic or have cardiovascular problems, you could be risking a heart attack or stroke, especially if you’re exerting yourself – like shoveling snow.

“We definitely know cold weather affects everybody’s physiology. Cold air, cold frigid water – there’s a lot of things that occur with exposure to cold,” said Elissa Thompson, MD, a cardiologist who works at Cape Cod Healthcare’s Cardiovascular Centers in Chatham and Hyannis.

“The natural response to cold is vasoconstriction,” when blood vessels contract in diameter, she added.

Vasoconstriction limits the amount of blood circulating near the skin, which raises blood pressure, according to an American Heart Association News article published in December. The colder it is, the stronger the reaction.

Physicians have known about the effect of cold on blood pressure for many years, Dr. Thompson said. Blood pressure levels peak in winter and hit bottom in summer in countries throughout the globe, and temperature is one of several possible contributing factors, said a 2013 article in the International Journal of Health Sciences.

Another frigid fact: Cold weather is associated with more cardiovascular illness and mortality.

A meta-analysis of 159 studies published last March in Frontiers in Cardiovascular Medicine found overall that for every drop of one degree Celsius, the rate of cardiovascular illness rose 1.2 percent and the rate of cardiovascular disease-related death rose by 1.6 percent. Cold spells had more dramatic effects, raising cardiovascular illness by 13.8 percent and death by 32.4 percent.

The researchers wrote that in addition to raising blood pressure, exposure to cold can cause other changes in the body, including affecting blood sugar levels, possibly triggering inflammatory and clot-making responses, and increasing platelets and red blood cells. Higher blood cell counts make blood more viscous, and could lead to a heart attack or stroke, according to the meta-analysis.

How to Lower Your Risk

“You should do everything you can (to be healthy). You’re not smoking. Take your medications before you go out and exercise,” Dr. Thompson said.

Cover up and don’t overdo outside activities, she advised.

“You really need to bundle up. It may sound like your mom telling you what to do, but there’s a lot of really good physiologic reasons to wear a hat, coat, scarf, mittens,” she said. It’s not just your skin that needs protection from wintery temps. Wearing a scarf over your mouth and nose can help counter sending cold air directly into your lungs, she said.

If you can’t get someone else to help you, break up outdoor tasks into smaller portions – don’t try to get it all done in one shot.

“Bite it off in small chunks. Say you just want to shovel off the front porch. Go out for 15 minutes, then come in,” Dr. Thompson said.

If you haven’t been exercising regularly, all that shoveling can strain your system, and the cold ups the ante, she said. People get deconditioned in the winter because they’re probably not going outside as much to exercise as they do in warmer weather.

She said those at risk of a cardiovascular event include older people, obese individuals, and those who have:

• Diabetes
• Hypertension (have high blood pressure)
• An existing cardiovascular condition, which might include atherosclerosis (buildup of cholesterol and plaque on arterial walls), heart failure (when the heart cannot effectively pump blood) or arrhythmia (irregular beating of the heart)

Even if you stay fit, your body’s ability to cope with added stresses declines with age, Dr. Thompson said. Age makes a difference when dealing with the cold. Plus, older people tend to have chronic illnesses.

Some people shouldn’t be shoveling snow or exercising outside in the cold at all.

“People who have (recently) had a heart attack, bypass surgery, a stent … they should allow time to recuperate,” Dr. Thompson said.

Play it smart and be safe, she advised.

“Exercise with a buddy,” she said. “If you’re going outside to shovel your driveway, make sure someone knows. Carry a cell phone – have a way to communicate. Ultimately, we want people to exercise and be outdoors.”