High blood pressure (Hypertension) is a common problem with a reported prevalence of around 30%. It is a common underlying cause of heart attacks, strokes and chronic kidney disease. What is the effect of winter on blood pressure has been an interesting subject of discussion.
It is a well-known fact that BP is invariably higher in colder months than in summer. This is true for both persons with hypertension and those with normal BP.
The reasons for this are multiple: Activation of body hormones like catecholamines (adrenaline, nor-adrenaline, etc) during cold, leads to increase in heart rate and constriction of blood vessels. In addition, the production of healthy hormones like nitric oxide which relaxes the arteries goes down.
The other factor linked to it is lower vitamin D levels because of less exposure to sunlight which leads to hormonal imbalance and activating kidney factors leading to higher BP readings. This combines with the other mechanisms leading to BP getting out of control even in those where it was well maintained during the summer months. Vitamin D supplements in winters are therefore recommended.
Raised levels of cholesterol even with a modest increase is an independent cause of increased BP, irrespective of age and the diabetic status etc. This again leads to the blood vessels getting constricted with reduction in the levels of protective hormones coming out from the blood vessel walls.
Physical activities in winter in general are considerably reduced and this again leads to increased BP. Exercise and the stress produced by this is very healthy for the blood vessels in the form of releasing good hormones.
Air pollution coming out of increased particulate materials, wood and fuel burning in particular to give warmth is an important factor which is injurious to the vessel walls leading to their getting constricted. This happens often when there are stagnant air columns in very low temperatures with low wind speed.
Higher levels of BP, diabetes getting out of control, increase in body weight and inflammatory illnesses like influenzas and pneumonias which are seen often in winter months result in various heart related problems. These lead to increased chances of getting a heart attack, stroke, heart failure and sudden cardiac death.
How to prevent winter related high BP and its aftermath?
Patients who are on treatment for high BP need to be vigilant and ensure that their blood pressure is close to 130/80 and in any case not more than 140/90 mms Hg. Many patients especially elderly ones need increase in doses or addition of drugs. Patients with co-morbidities like diabetics, previous strokes and chronic kidney disease (high creatinine levels) need to be extra careful. Home BP monitoring is the way to go because going to a clinician in inclement weather is not easy.
Everybody should know his/her blood pressure. If you don’t know, it is important to get it checked. Early detection of hypertension and its management is very important. Remember high BP most often does not have symptoms that is why it is also called a “silent killer”.
For its treatment non-drug measures are extremely useful. They do not have any side effects and are very cost effective. Adoption of these in known patients leads to lesser need of medicines.
Regular Physical Exercise: In the form of walks at a time when it is not too cold and wearing a suitable attire which protects from very low temperatures. A target of around 8,000 steps per day at least 5 times per week should be the target for healthy persons.
Keeping Warm: Clothes with more than 2 layers of warm clothing which traps air and keeps you insulated is desirable. These don’t have to be very heavy. Keep the home warm with at least one room maintaining a good temperature of around 20 to 24 degrees Celsius.
Avoid electric blankets which have led to disasters in some instances. Hot water bottle is a good alternative. Besides keeping warmth relieves stress, eases aches and pains and help in getting good sleep.
Healthy Food for keeping BP low
Plenty of green leafy vegetables which are available in plenty, Collard leaves (Haakh), Spinach (Palak), Amaranth (Chaulai) beans, lentils, carrots, radish, citrus fruits (oranges, lime and lemon), pumpkin seeds and fatty fish (Mackerel, Herring Salmon and rainbow trout). Do not overcook which destroys all the good properties. Mutton our staple food should be regulated and preferably be added to vegetables. White meat, chicken and fish should be preferred.
Reduce the amount of carbohydrates (rice and breads) and consume fats in moderation and have good portions of proteins.
Take Home Message
Winter months lead to higher blood pressures for healthy individuals and for those with known hypertension. There are several mechanisms for it, which include the cold temperature itself, lack of physical activity, seasonal variations in body hormones, increased cholesterol levels and reduced vitamin D intake.
The measures to counter it in addition to drugs are keeping warm, increasing physical exercises, consuming BP lowering diets in plenty which are rich in vegetables and fruits.
Prof. U Kaul Founder Director, Gauri Kaul Foundation. Recipient of Padma Shri and Dr B C Roy Award
Disclaimer: The views and opinions expressed in this article are the personal opinions of the author.
The facts, analysis, assumptions and perspective appearing in the article do not reflect the views of GK.