Snow shoveling increases risk of heart attack in men, says new study

Heavy snowfalls have been linked to an increase in hospitalizations and deaths due to cardiac events, according to new study published in the Canadian Medical Association Journal.

Researchers at the University of Montreal analysed over 100-thousand hospital admissions and almost 70-thousand deaths due to heart attack over three decades in the province of Quebec. They found the likelihood of a heart attack increased the day after a snowfall among men, but not women. This could be because men were more likely to take on the job of shoveling.

“We suspect that shoveling was the main mechanism linking snowfall with myocardial infarction (heart attack),” Dr. Nathalie Auger of the University of Montreal Hospital Research Center and colleagues wrote.

“Men are potentially more likely than women to shovel, particularly after heavy snowfalls. Snow shoveling is a demanding cardiovascular exercise requiring more than 75 percent of the maximum heart rate, particularly with heavy loads,” they added.

The team studied 128,000 heart attack cases between 1981 and 2014, and more than 68,000 people who died.

A single day of snowfall raised a man’s risk of heart attack by just less than 1 percent, they wrote, and it raised his risk of dying from a heart attack by 12 percent.

Eight inches of snowfall raised the risk 16 percent compared to a day in the same month that did not have snow, they reported, and men were one-third more likely to die of a heart attack the day after an eight-inch snowfall, compared to a dry day.

Women were not more likely to either have heart attacks or to die of them after snow, the team found.

Snow shoveling is hard. It’s not a daily activity, and it strains the heart, Auger’s team said. People often exhale hard with their mouths closed while lifting a heavy shovel full of snow, a dangerous habit called the Valsalva maneuver, they noted.

Using the arms intensively and repetitively, especially while standing upright, can also raise the risk that a piece will break off from a clogged artery, the researchers noted. Cold temperatures make blood vessels constrict, which adds to the danger.

It might not only be shoveling that does it. People using snow blowers have also been reported to have higher rates of heart attack, the Canadian team noted.

The following tips can help keep you safer when you set out to shovel:

• Warm up. Warm your muscles before heading out to shovel by doing some light movements, such as bending side to side or walking in place.
• Push rather than lift. Pushing the snow with the shovel instead of lifting can help reduce the strain on your body. When lifting snow, bend your knees and use your legs when possible.
• Choose your shovel wisely. Ergonomically-designed shovels can help reduce the amount of bending you have to do.
• Lighten your load. Consider using a lighter-weight plastic shovel instead of a metal one to help decrease the weight being lifted.
• Hit the pause button. Pace yourself and be sure to take frequent breaks. Consider taking a break after 20 to 30 minutes of shoveling, especially when the snow is wet.
• Consider multiple trips. Consider shoveling periodically throughout the storm to avoid having to move large amounts of snow at once.
• Keep up with snowfall. Try to shovel snow shortly after it falls, when it is lighter and fluffier. The longer snow stays on the ground, the wetter it can become. Wet snow is heavier and harder to move.
• Wear layers. Dress in layers and remove them as you get warm to help maintain a comfortable body temperature.
• Stay hydrated. Drink plenty of water to stay hydrated while shoveling.

Agencies/Canadajournal