Normal blood pressure should not exceed 140 mmHg (mm of mercury) for the first number, and 90 mmHg for the second. When the values are higher, we speak of high blood pressure. “This corresponds to an increase in pressure on the vessel wall. There is a loss of flexibility of the arteries“, explains Dr Alexandre Bensaid. Hypertension has a considerable impact on health, in particular it increases the risk of stroke by five and the risk of myocardial infarction by four. Among the contributing factors, we can mention sedentary lifestyle, being overweight, lack of physical activity, excessive alcohol consumption and cardiovascular factors such as diabetes, cholesterol, smoking.
What is the impact of cold on health?
Unsurprisingly, it is mainly cold countries that are interested in the impact of cold on health, particularly cardiovascular health. Canada and Sweden have notably conducted studies on the subject. “If we look at the epidemiological mortality series in a country, we realize that the cold has a real impact. Thus, in Canada, nearly 4% of mortality could be statistically attributed to cold”, observes Dr. Bensaid. Several studies have also established a relationship between blood pressure (BP) and outdoor temperature, with the highest pressures recorded at a cold temperature and the lowest pressures at a relatively warm temperature.
Why does cold have an impact on blood pressure?
The deleterious effects of cold on high blood pressure are linked to a reaction to cold, and therefore to skin coldness. “In the event of very cold temperatures, the body will respond with vasoconstriction, which occurs via the sympathetic system. Hormones secreted on brain command will cause the vessels to tighten to counter the cold in order to increase the oxygen supply to the tissues.”, explains the cardiologist. This phenomenon therefore results in an increase in blood pressure. Dr Bensaid points out that the management of hypertensive patients is nevertheless the same whether it is cold or not: regular monitoring of blood pressure figures and the prescription of appropriate treatment. No particular therapeutic adaptation is therefore necessary.
Extreme cold: what precautions should I take if I suffer from hypertension?
Although the cold does not have a direct impact on heart rate, we do know that there is a greater increase in heart rate when practicing intense physical activity in cold conditions.
We therefore understand that a subject who is fragile on a cardiovascular level has a greater risk of complications linked to the cold or linked to the practice of physical effort in very low temperatures. “However, the impact of cold remains complicated to quantify because it is very difficult to isolate any particular factor in the statistics. But we know that there are more myocardial infarctions, angina pectoris, aortic dissections, and even strokes when it is cold.”, explains Dr. Bensaid. “If you are cardiovascularly fragile, you should therefore avoid making unusual efforts when it is cold. And be monitored, in particular by taking blood pressure, if there is the slightest doubt”, recommends the cardiologist.
Thanks to Dr Alexandre Bensaid, cardiologist.
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