Winter is known to increase the chances of heart attacks and related problems. This is especially true for those who have one or more risk factors. The well-known risk factors are high blood pressure, diabetes, tobacco use, obesity, high blood cholesterol levels etc.

Why winter

•The changed daylight hours adversely affect the hormone balance. Cortisol levels in the blood are altered. This is one of the possible reasons for increase in heart attacks.

•The low temperatures lead to tightening or constriction of blood vessels. This reduces the blood supply to the heart. This can aggravate angina and lead to blockage of an artery leading to heart attack.

•The oxygen demand of the heart increases because the heart has to work harder to keep the body warm.

•The early morning surge of blood pressure is an important reason for heart attacks being more common in the morning. In winter because of shorter day light hours, people often have a tendency to do outdoor work in the day. The combination of cold and hard work leads to higher blood pressure.

•The shift of activities to morning hours leads to an addition to the normal circadian rhythm leading to increase in heart rate, blood pressure and cortisol levels. This combination reduces the threshold of events like heart attack and brain stroke etc.

Migrating to warmer places not a great help

It has been seen that people at risk who migrate to relatively warmer places during the colder months can get caught with cardiac problems there too, due to infections. Inflammation produced by illnesses like influenza can lead to swelling in arteries of the heart and lead to heart attacks.

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