Physical activity is essential for safeguarding heart health. As far as young people are concerned, this is true provided that the sport is not carried out outdoors on days when air pollution levels are high. In those cases, in fact, often the risks of cardiovascular diseases would exceed the benefits given by sport.
To say it, a new Korean study published in the European Heart Journal and which involved almost 1.5 million people.
of the South, led by Professor Sang Min Park, tried to shed some light on this aspect by examining information from the National Health Insurance Service on 1,469,972 young Koreans between the ages of 20 and 39, living in different cities.
The sample that took part in the research was observed for several consecutive years and subjected to two control screenings every 1-2 years.
The same team of researchers had previously carried out a study on the subject, however, involving middle-aged people. This, on the other hand, is the first time that the target taken into consideration is that of younger people.
How it unfolded
At each health check, participants completed a questionnaire, providing information on their physical activity over the past seven days. This information was then converted into minutes of metabolic activity per week (MET-min / week) and, based on the results, the juveniles divided into four groups: 0, 1-499, 500-999 and 1000 or more MET-min /week.
The guidelines of the European Society of Cardiology recommend people to do 500-999 MET-min / week and this is equivalent to running or cycling for 15-30 minutes five times a week or brisk walking for 30-60 minutes five. times a week.
Regarding pollution levels, the researchers took into account in particular the levels of PM10 and PM2.5, breaking them down into low, moderate and high.
, such as stroke and heart attack, increases with decreasing amount of physical activity between two screening periods, in the group with low levels of exposure to air pollution. However, in the group with high levels of exposure to air pollution, increase the amount of physical activity at more than 1000 MET-min / week could adversely affect cardiovascular health. This finding is very important and suggests that, unlike people over 40, "excessive physical activity may not always be beneficial to the cardiovascular health of younger people when they are exposed to high concentrations of air pollution."
Specific data
In detail, 8,706 cardiovascular events occurred during the follow-up period.
Among people exposed to high levels of PM2.5 air pollution, those who increased their exercise from 0 to 1000 MET-min / week or more, between the two screening periods had a 33% increased risk of cardiovascular disease compared to those who were physically inactive and had not increased their level of exercise.
Among people exposed to low to moderate levels of PM2.5, those who increased physical activity from none to 1,000 MET-min / week or more had a 27% reduced risk of developing cardiovascular disease, compared with those that have remained inactive.
Finally, for low to moderate levels of PM10 air pollution, there was a statistically significant 38% or 22% increase in the risk of cardiovascular disease among people who started doing 1000 MET-min / week or more. and then reduced their activity to zero, or 1- 499 MET min / week, compared to people who maintained the same high level of activity. These statistically significant results show that 74 and 66 out of 10,000 people, respectively, would develop cardiovascular problems during the follow-up period.
Conclusions
According to Professor Sang Min Park, who led the research, "Our results show that when air pollution levels are high," exercise beyond the recommended amount can offset or even reverse the beneficial effects. "
The study, however, has limitations, as it cannot prove that air pollution causes increased cardiovascular risk, only that it is associated with it.
Despite this, as underlined by the team of researchers, "lowering the level of air pollution should be a priority global objective, also in order to maximize the health benefits of" physical exercise in young adults ".
