According to a study published in the European Heart Journal, owning a car and a television is associated with an increased risk of heart attacks, particularly in low- and middle-income countries, while physical activity during leisure time or work considerably reduces the risk of heart attacks in developed and developing nations.
The INTERHEART case-control study involved more than 29,000 individuals from 262 centers in 52 countries in North and South America, Europe, Africa, the Middle East, Asia and Australia.
Professor Claes Held, associate professor at Uppsala Clinical Research Center and the Department of Cardiology, at Uppsala University Hospital Sweden, as well as lead author of the investigation explained:
“Until now, few studies have looked at the different aspects of physical activity both at work and during leisure time in relation to the risk of heart attacks.
Much is already known about the association between physical activity and cardiovascular risk, but what this study adds, among many other things, is a global perspective. The study shows that mild to moderate physical activity at work, and any level of physical activity during leisure time reduces the risk of heart attack, independent of other traditional risk factors in men and women of all ages, in most regions of the world and in countries with low, middle or high income levels. Interestingly, heavy physical labour at work did not protect against heart attacks.
These data extend the importance of physical activity and confirm a consistent protective effect of physical activity across all country income levels in addition to the known benefits of modifying traditional risk factors such as smoking.
Furthermore, ownership of a car and TV, which promotes sedentary behavior, was found to be independently associated with the risk of heart attacks.”
Together with colleagues from the USA and Canada, Prof. Held compared leisure and work habits of 10,043 individuals who had suffered their first heart attack with 14,217 healthy individuals in the control group.
Participants were asked if their work was primarily sedentary, or generally walking at one level, or predominantly walking including lifting heavy objects, walking uphill, or heavy physical labour.
Participants were asked to select from four categories regarding their physical activity during their leisure time:
- Predominantly sedentary, such as reading, watching TV, and sitting
- Mild exercise, such as yoga, easy walking, and fishing
- Moderate exercise, such as cycling, light gardening, or walking for a minimum of 4 hours per week
- Strenuous exercise, such as football, vigorous swimming, or running
In addition, participants were asked whether they owned a car, TV, land, computer, radio/stereo, and livestock.
After the team adjusted for various factors, such as sex, country, income, age, alcohol, smoking, diet, health, education etc., they discovered that individuals whose work involved mild physically had a 11% lower risked of having a heart attack than individuals whose work was primarily sedentary. Individuals whose work involved moderate physical activity had a 22% lower risk, while heavy physical labour did not lower the risk at all.
Mild exercise during leisure time lowered the risk of having a heart attack by 13%, while moderate or strenuous exercised lowered the risk by 24% when compared with individuals mainly sedentary.
Individuals who owned both a TV and car had a 27% increased risk of experiencing a heart attack than individuals who did not own a TV and car.
Compared to people in middle- and high-income countries, more individuals in low-income countries engaged in less physical activity in their leisure time and had sedentary jobs.
The researchers explain:
“These differences in PA [physical activity] were more pronounced regarding leisure-time activity. This may partly be explained by differences in education and other socioeconomic factors. In addition, this may also reflect differences in culture and in climate. The likelihood of a subject performing leisure-time PA in tropical or hot climate zones is lesser than in more temperate areas of the world.”
According to the researchers all individuals should be encouraged to participate in daily moderate physical exercise in order to prevent heart disease.
Prof. Held said:
“The data have some real-life implications. One suggestion may be for the lower income countries to be more involved in promoting physical activity as their societies starts to use more labour-saving devices, so as to counter-act the inactivity that this can lead to; however, it is also important to promote physical activity in all parts of the world.”
In an associated report, Drs. Emeline Van Craenenbroeck and Viviane Conraads from Antwerp University Hospital, Belgium, explain:
“Two main questions were tackled [by the INTERHEART study]: do the different constituents of daily physical activity (work or leisure) diverge in their ability to reduce the risk of AMI (acute myocardial infarction) and, secondly, are potential markers of a sedentary lifestyle, such as owning a car or a TV, associated with increased cardiovascular risk? The answer to both questions seems to be a heartfelt ‘yes’.”
According to the researchers, the risk of a heart attack was lowered even in individuals who exercised well below currently accepted guidelines for activity. In addition, they highlight that this may be “particularly useful when it comes to motivational strategies.”
The researchers conclude:
“Although timely and highly relevant, the paper of Held et al. Leaves clinicians with the Herculean task of translating this evidence into effective preventive care. If we want to support healthy longevity, we should put a stop to the pandemic of sedentarism.
Staying physically fit throughout life may well be one of the easiest, cheapest, and most effective ways to avoid the coronary care unit.”
Written by Grace Rattue