By Sumarbin Umdor
September 29, is observed as World Heart Day, a global campaign to raise awareness about cardiovascular diseases (CVD), including heart disease and stroke, which claims more than 17.7 million lives every year representing 31 per cent of all global deaths. Of these deaths, an estimated 7.4 million were due to coronary heart disease and 6.7 million due to stroke accordingly to World Health Organisation.
A recent article in The Lancet, a prestigious medical journal, published in September of 2018 documents cardiovascular disease trends in India for a period stretching over a quarter of a century. It reveals that CVD are the largest contributor to disease burden of any disease group and are a major public health problem leading to premature deaths and morbidity across all states of India. The contribution of CVD to total deaths and disease burden in India has almost doubled since 1990 and it is increasing across the country including the rural areas. This category of diseases is now the leading cause of death among both communicable, maternal, neonatal, and nutritional diseases and non-communicable diseases. In 2016, CVDs were responsible for 28.1 per cent of total deaths in the country compared to 15.1 per cent in 1990.
The paper also reports that individually Ischaemic heart disease (also known as coronary heart disease) and stroke are the predominant CVD responsible for 17.8 and 7.1 per cent of the overall total deaths in 2016. These two diseases occupy the first and fifth position respectively in terms of leading individual cause of disease burden in India. The proportion of deaths from Ischaemic heart disease was significantly higher in men than in women, but similar in the two sexes for stroke. Further, the prevalent cases of CVD increased from 25·7million in 1990 to 54·5 million in 2016.CVD death rate in India at 272 per 100000 population in India is higher than the global average of 235 per 100000 population.
The most important behavioural risk factors of heart disease and stroke are unhealthy diet, physical inactivity, tobacco use and harmful use of alcohol. About 80 per cent of premature deaths from heart disease and stroke could be avoided by controlling the above risk factors. There are also a number of underlying determinants of CVD or “the causes of the causes”. These are a reflection of the major forces driving social, economic and cultural change – globalization, urbanization and population ageing. Other determinants of CVDs include poverty, stress and hereditary factors.
Scientific evidence shows that individuals who engage in regular exercise have lesser chances of developing heart disease than their sedentary counterparts. This benefit of exercise has been recognized since the epidemiological studies of Morris who in the 1950s reported lower rates of coronary heart disease among the conductors of London’s double-decker buses compared with the drivers. Many subsequent studies of diverse populations confirmed that regular exercise was associated with a substantially reduced risk of heart attack and cardiovascular death. One such study concluded that compared with the least active participants, the most active men and women had risk reductions of 30 to 35 per cent from incident coronary artery disease.
Accordingly to an article in the Journal of American College of Cardiology, regular exercise has a favorable effect on many of the established risk factors for cardiovascular disease by reducing bad cholesterol levels in the blood (the low-density lipoprotein [LDL] level), as well as total cholesterol, and can raise the good cholesterol (the high-density lipoprotein level [HDL]), lowering blood pressure, improving glucose metabolism and insulin sensitivity, reducing body weight, and reducing inflammatory markers . These risk factor improvements explain 59 per cent of the reduction in CVD. The remaining 41 percent may result from improved endothelial function, enhanced vagal tone producing lower heart rates, vascular remodeling including larger vessel diameters, and an enhanced nitric oxide bioavailability.
There are a number of randomized clinical trials assessing the benefits of exercise training and cardiac rehabilitation on CVD in select patient populations. These studies show that patients with diagnosed heartdisease who participate in an exercise program reported reduced incidence of cardiovascular mortality and heart failure hospitalization, along with an earlier return to work and improvements in other measures of quality of life, such as more self-confidence, lower stress, and less anxiety.
CVD represents a leading cause of mortality and morbidity especially among the elder people, and therefore the need of effective preventive strategies is imperative. In a review of studies that have investigated physical activity exclusively in the elderly, Chen and others in their article in the International Journal of Gerontology reported that majority of published studies have demonstrated physically active experienced up to 50 per cent reduction in coronary heart disease mortality compared to their less active counterparts.
So how much should one exercise or involve in physical activity on a daily basis to derive the benefits from it? The technical definition of physical activity is ‘any bodily movement produced by the contraction of skeletal muscles, which results in energy consumption beyond resting expenditure or anything that moves the body and burns calories. The US guidelines recommend at least 30 minutes of moderate-intensity aerobic activity of 5 days per week or at least 25 minutes of vigorous aerobic activity at least 3 days per week. However, according to an article by Dr. Simon published in The American Journal of Medicine, even as little as 15 minutes of moderate exercise (at an intensity that the breathing is faster and one is able to talk but not sing) a day is extremely beneficial, reducing all-cause mortality rates by 14 percent and adding 3 years to life expectancy. After a review of 22 studies that evaluated how moderate physical activity affects the risk of heart attack, stroke, and the all-cause of mortality rate, he concluded that even a modest activity of as little as one hour of walking or gardening per week was associated with major benefits fully comparable to the health benefits linked to aerobic fitness.
In a significant development in understanding the health benefits of exercise, a review of evidence by researchers published in the British Medical Journal on the comparative effectiveness of exercise versus drug intervention on mortality outcome concluded that physical activity is potentially as effective as many drug interventions for patients with existing coronary heart disease, stroke and diabetes. They argued that exercise interventions should therefore be considered as a viable alternative alongside, drug therapy, and that an “exercise pill” is an essential preventive strategy to reduce morbidity and mortality.
The scientific evidence is therefore clear and strong about the positive benefits of exercise on preventing heart disease, stroke and other illness. However, why people are reluctant to exercise is hard to comprehend. One reason given by most is the lack of time. On this, Edward Stanley, the Earl of Derby, got it right when in an address he gave at Liverpool College in 1873 said, “Those who think they not have time for bodily exercise will sooner or later have to find time for illness.”
(Prof. S. Umdor is the Teacher-in-charge of Sports, NEHU)