CVDs become deadlier in extreme cold weather

Rawalpindi: The mortality rate due to cardiovascular diseases (CVDs) becomes the highest during the extreme cold weather conditions in winter and according to health experts, it is time for the chronic patients suffering from any of the CVDs to take extra care of their diet and routine.

Cardiologists believe that the heart patients become more vulnerable to serious and life threatening complications in extreme cold. Studies have revealed that both the incidences of CVDs and the number of deaths due to CVDs get higher in the colder months of the year. The incidences of CVDs and their complications are associated with the risk factors like temperature, physical activity, air pollution, infections, and dietary habits. According to experts, chronic patients need to change their lifestyle during the winter to avoid the risk of life threatening complications. Heart patients must follow the precautionary measures to avoid bad effects of harsh weather.

The CVDs including stroke, intracerebral haemorrhage, hypertension, heart failure, angina pectoris, myocardial infarction, sudden cardiac arrest, ventricular arrhythmia, deep venous thrombosis, pulmonary embolism, aortic dissection and rupture, and atrial fibrillation are considered as more deadly during the winter than in summer. A number of studies carried out in France, Spain, Japan, Scotland, Australia, Brazil, Argentina, Italy, Turkey, Nigeria, Canada, and USA revealed that admissions of heart patients to hospitals register a significant increase during the winter season and show decline in the summer season and the same is the trend in Pakistan.

Exposure to extreme cold increases the peripheral vasoconstriction (the narrowing of the blood vessels), which may lead to pulmonary oedema (a condition in which the lungs are filled with fluid, also known as lung congestion) as a consequence of left ventricular failure and may also cause abnormal clotting.

Also both the systolic and diastolic mean blood pressures exhibit a seasonal peak during winter and trough in summer among adults, the elderly, and children. The extreme cold has a significant effect on blood pressure among both the healthy people and patients suffering from hypertension.

Studies reveal that potentially important seasonal risk factors like the seasonal variation in the plasma level of fibrinogen, cholesterol, hormones and vasoactive substance including vasopressin (AVP), norepinephrine (NE), epinephrine (E) and angiotensin II, aldosterone and catecholamine which tends to rise in the winter and play an important role in the seasonal change of CVDs. Exposure to extreme cold affects the pumping power of the heart muscle in patients with symptomatic congestive heart failure and it also affects the exercise capacity of heart patients that may cause serious complications.