When air pollution levels are high, physical activity that exceeds recommendations from cardiologists can be hazardous to heart health. However, the recommended level of activity is always healthier than a sedentary lifestyle. This was shown by a study published in the European Heart Journal.
Diseases of the cardiovascular system (CVD ) is the leading cause of death worldwide. One of the most important measures to prevent them is physical activity.
In today's world, people often have to walk, run, ride a bike and do other exercises in polluted air. Previously, scientists have found that pollution with particles with a diameter of 2.5 to 10 micrometers (PM2.5 and PM10) is associated with an increased risk of CVD. Thus, polluted air has the potential to reduce the degree of protection against CVD that physical activity provides. Until now, little was known about the impact on heart and vascular health of exercise at potentially harmful levels of air pollution.
In a new study, researchers at Seoul National University analyzed data on nearly 1.5 million people aged 20-39. The study participants lived in Korean cities. They were followed from 2013 to 2018, during which time they underwent two medical examinations. Young people periodically filled out questionnaires in which they talked about their physical activity during the last week.
The scientists measured the physical activity experienced by study participants in metabolic equivalents (METs). 1 MET is the amount of energy that a person burns at rest, equals approximately 1 kilocalorie per kilogram of body weight per hour. During moderately heavy physical activity, a person spends about 3-6 times more energy. The European Heart Society recommends 500-999 METs of physical activity per week (15-30 minutes of moderate-intensity exercise 5 times a week).
«We found that in people 20-39 years old, the risk of cardiovascular disease increased with a decrease in physical activity,» said Dr. Seong Rae Kim, co-author of the study.
< span>At the same time, Kim reported, physical activity of more than 1000 METs per week (which is above the usual recommendations) in polluted air (PM2.5 particles concentration above 26.46 micrograms per cubic meter) can be dangerous for heart and vascular health. That is, under such conditions, high activity can be more harmful than physical inactivity.
With lower air pollution, any activity, including intensive, was useful.
Overall, our data show that physical activity at levels recommended by the European Society of Cardiology is associated with a reduced risk of cardiovascular disease in young people. But when pollution levels are high, exercising more than the recommended amount can be harmful,” concluded Sang Min Park, lead author of the study.