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The question: Am I more likely to have a heart attack in the winter? My dad, who's in his early 70s, has high blood pressure and had a mild heart attack two years ago. I've read online that there is an increased risk in the cold. Is this true?

The answer: Your online research is correct: There is an increased risk for heart attacks in the winter months when compared to other times of the year.

When it's cold out, your heart works harder to maintain body heat. Exposure to cold also causes our blood vessels to constrict and our blood pressure to rise, which can put strain on the heart. When all these factors combine, the risk of heart attack increases, especially in the elderly or those with existing heart disease.

Another contributing factor is cold-and-flu season. Any increase of inflammation in the body can increase heart-disease risk, and in the winter months, the leading causes of inflammation are respiratory tract infections like the cold or flu. When we fight the flu, it not only causes a strain on the lungs, but also on the heart. A recent study has shown that those who receive the flu shot have a reduction of heart attacks. So consider getting the shot, especially if you're at increased risk, or urge a loved one to if they are elderly or have a history of heart disease.

According to the Heart and Stroke Foundation of Canada, certain winter activities, especially those done in cold weather such as snow-shovelling, may also increase our risk. One study found that 7 per cent of winter heart-attack victims in a Canadian hospital had been shovelling at the time of their incident.

While exercise helps protect the heart, extreme weather conditions can make the activity more strenuous. Exercising in low-temperatures can cause a rise in blood pressure and heart rate, and increase the risk of blood-clotting. If you have a risk of heart disease or have already been diagnosed with high blood pressure or high cholesterol, or have had a previous heart attack or stroke, use caution and check in with your doctor for advice on safe activities.

Let's not forget that there is much holiday time with family during the winter months. The holidays can result in a change in sleep patterns, increase our intake of unhealthy foods and decrease physical activity. With the bustle of the season, we can sometimes forget to take our medications and our stress levels can rise, which can increase our blood pressure. It's also been found that when we're with family and celebrating the holidays, it can be easy to ignore symptoms of heart attack, which can result in delays in seeking care.

While heart attacks do increase in the winter months, minimize your risk by maintaining a healthy diet, taking on safe activities despite the colder weather, and seeking care if you have symptoms. For more information on heart disease and stroke, visit the Heart and Stroke Foundation of Canada.

Dr. Sheila Wijayasinghe is the medical director at the Immigrant Womens' Health Centre, works as a staff physician at St. Michael's Hospital in their Family Practice Unit and at Hassle Free Clinic, and established and runs an on-site clinic at Women's Habitat Shelter in Etobicoke.

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