Be heart-smart in winters

Dr Harinder Singh Bedi

Winter is the most vulnerable time for patients of heart disease. Heart attacks peak during the winter months and an attack in this season is also more likely to be fatal. Various studies have corroborated this fact. A research by the American Heart Association states that people with coronary heart disease (CHD) often suffer from angina (chest pain or discomfort) in winters. According to Harvard Health Publication 2016, cold weather can create a storm of risk factors for cardiovascular problems. 

Winter reduces the supply of oxygen-rich blood to the heart muscle. The cold weather also forces the heart to work harder because of which the heart demands more supply of oxygen-rich blood. This mismatch between the demand and supply of oxygen-rich blood to the heart increases the risk of an attack. 

Other problems like high blood pressure, angina, myocardial infarction, heart failure, sudden cardiac death, ventricular arrhythmias, atrial fibrillation and pulmonary embolism also increase in the cold season, according to a study published in The North American Journal of Medical Sciences. 

Winter poses a danger to heart health as well as for people with heart disease for a wide variety of reasons. 

Constriction of arteries: When a person gets exposed to cold weather, the body's automatic response is to narrow the blood vessels so that the body heat is retained. In people with coronary artery disease (CAD), blood vessels are already filled with cholesterol plaque. In such cases, narrowing of blood vessels increases the risk of a blockade leading to ischemia (lack of blood) and a heart attack. 

Raised blood pressure: The narrowing of vessels causes an increase in blood pressure, which puts strain on the heart. The heart has to work harder due to the raised blood pressure and its blood supply is reduced due to constriction of blood vessels. This may be tolerated well by a normal heart, but in a diseased heart it can precipitate a heart attack.

Thicker blood: In cold weather, platelets appear to become more active. Therefore, blood is more likely to clot and trigger a heart attack. The levels of cholesterol also rise during winters. Studies also show that when it is cold, the concentration of a protein called fibrinogen in the blood increases, raising the chances of clotting of blood. Over-eating: People tend to eat and drink more and gain weight during winter months which is bad for the heart.

Stress and depression: Daylight hours decrease during winters. This causes an increase in stress hormones like cortisol in the body. Also, the lack of exposure to sufficient sunlight in winters increases the incidence of depression and people with depression are more susceptible to heart attacks.

Less sunlight: Decreased hours of sunlight in winters lower the vitamin D levels in the body. Low levels of vitamin D are by themselves linked to heart disease. Production of vitamin D through exposure to sunlight suppresses calcification or hardening of blood vessels. The deficiency of this vitamin leads to arterial stiffness, a major risk factor for cardiovascular diseases.

Pollution: Pollution and smog make the air unhealthy. Polluted air damages lungs; the impaired lungs then produce low levels of oxygen, which further strains the heart.

Influenza/pneumonia: Winters also increase chances of respiratory infections. These can have many adverse effects on the heart.

Respiratory infections increase the levels of C-reactive protein (CRP) and fibrinogen in the blood. The CRP is a marker of inflammation and elevated levels of CRP are associated with incidence of increase in heart disease up to three times.

Flu and other respiratory diseases in winters cause inflammation of arteries, which makes plaque in the blood vessels unstable and may cause it to rupture, causing a heart attack. 

These infections can increase the blood pressure. Heart patients affected with flu, cold or cough, should always consult a doctor before taking any over-the-counter decongestants. as many decongestants contain pseudo ephedrine and phenylephrine that can raise blood pressure and increase the chances of an attack.

— The writer is a cardiac surgeon, Ludhiana Mediways Hospital

Some basic precautions 

• Stick to a normal exercise routine, but avoid early morning walks. 
• Wear proper clothes. To minimise any risk to the heart or the circulatory system, keep warm by wearing layers of clothing. This traps air between the layers, forming a protective insulation. Get indoors immediately if at anytime your body can still not handle the cold. 
• Keep the house well heated by letting in sunlight. If you have central heating, keep the temperature between 18°C and 21°C. Keep hands and feet as these tend to lose heat quickly. On extremely cold nights, opt for a hot water bottle or electric blanket.
• Avoid tobacco, coffee or tea to warm up. Nicotine and caffeine put stress on the heart. 
• People at risk can reduce their overall risk by managing modifiable risk factors like high blood pressure, diabetes and high cholesterol with regular medication.
• Avoid or limit alcohol intake. Stick to one to two drinks a day. Too much alcohol consumption can cause atrial fibrillation and arrhythmia (irregular heartbeats) that can lead to blood clots, heart failure and stroke.
• Let a gym trainer chart an exercise routine. The cardiovascular system can adapt to slow and progressive changes in physical activity. Adapting to sudden changes can be dangerous. Beginners should not overexert all of a sudden, as unaccustomed exercise is not good for the body.
• Consume a healthy diet. Eat vegetables, fruits, nuts, whole grains and proteins (lentils/dal, beans, fish and low-fat dairy products). Have high-fibre foods like oats and legumes and use heart-healthy cooking oils. 
• Avoid fatty, fried and non-vegetarian food. Eat in moderation foods like red meat, egg yolk and full-fat dairy products. High levels of total cholesterol and LDL (bad cholesterol) are linked to incidence of coronary heart disease.
• Sit in the sun to improve your spirits and levels of vitamin D.
• Get vaccinated against Influenza.
• Don't ignore any symptoms of illness. If you feel unwell, consult your doctor immediately. 
• Maintain proper body weight. Minimise the intake of rapidly digested simple carbohydrates like white bread, white rice and potatoes. Avoid excessive sugar and salt, processed foods and soft-drinks to avoid weight gain.