In the wake of the heavy lake-effect snow that buried Buffalo, New York, in late November, at least two people were killed as a result of heart attacks after shoveling, according to the Associated Press. Though the events were tragic, they are not all that surprising, doctors say.
"It has been shown by many, many studies that there are more heart attacks in the December-January timeframe," Doctor Samin Sharma, director of Clinical and Interventional Cardiology at The Mount Sinai Hospital in New York, said.
While intense cardio exercise certainly puts a strain on the heart, cold weather is an exacerbating factor which leads to an increase in heart-related failures and fatalities over the winter season.
These factors can even put an otherwise healthy person at risk.
Cold weather causes the arteries to constrict, which then raises blood pressure and pulse rate. These increases put additional strain on the heart.
"That is a perfect storm, in my opinion, to have a heart attack in cardiac patients," Sharma said.
Additionally, hormonal changes that come with the colder weather can make blood more conducive to clotting.
Cortisone levels in the wintertime fluctuate with the colder weather, causing platelets to become ‘sticky,' Sharma said. These sticky platelets allow clots to form more easily. As the arteries constrict due to cold air, blockages increase.
"Blockages that were 60 percent may now be 75 or 80 percent," Sharma said.
When performing intense cardio exercise during the winter months, such as running long distances or shoveling snow, dress warmly and wear layers to keep your body temperature high, preventing inflammation and constriction.
Cardiac patients should avoid strenuous wintertime activity altogether.
Though it's a simple solution, one must also compensate for the lack of exposure to sunlight, Sharma said.
New research suggests that decreased exposure to sunlight may factor into the wintertime heart attack equation.
As the air gets colder, people bundle up before spending time outdoors, leaving less skin to be exposed to the UV rays which aid in the body's vitamin D production.
"In the winter, traditionally, your days are shortened, you have less sun so you have less production of vitamin D," Sharma said. Vitamin D works as a vitamin for the arteries, preventing inflammation and improving their function.
A vitamin D deficit can accentuate the inflammation of the arteries.
Sharma recommends regular exposure to sunlight in the cold weather months and adding, with a physician's consent, both an over-the-counter vitamin D supplement.