The busy life that millennials lead – people born between 1981 and 1994, although this may vary depending on the source consulted – includes long trips by car or other means of transport, working days in front of the computer or taking calls, and evenings and weekends during the week or on holidays watching television or consulting social networks, which results in a balance of more than 60 hours per week sitting. Now, a new study has revealed that this could increase your risk of developing heart disease, as well as speeding up other signs of aging.
The research has been carried out by experts from the University of Colorado Boulder and the University of California Riverside, who have analyzed data from more than 1,000 people – including 730 twins – to determine how the time they spent sitting affected health indicators such as cholesterol and Body mass index (BMI) in young adults.
This study is one of the first to analyze this impact in people between 28 and 49 years old, with an average age of 33 years. Their results have been published in PLOS One and have revealed that meeting the minimum physical activity guidelines – about 20 minutes of moderate exercise a day – is not enough to counteract the negative effects of spending most of the day sitting.
“Our research suggests that it may be necessary to sit less during the day, do more vigorous exercise, or a combination of both, to reduce the risk of premature aging in early adulthood,” said Chandra Reynolds, professor in the Department of Psychology and Neurosciences and the Institute of Behavioral Genetics and lead author of the study, in a note published by the University of Colorado Boulder.
Youth, a key stage to delay the signs of aging
Ryan Bruellman, lead author of the study and a doctoral candidate in the Department of Genetics, Genomics and Informatics at UC Riverside, became interested in this topic when he noticed that, after the pandemic, he and other young people were spending much more time sitting. “Young people often think that they are immune to the effects of aging. They say to themselves, ‘My metabolism is great, I don’t have to worry until I’m 50 or 60,’” Bruellman says. “But what you do during this critical time in life is important.”
Walking after work is not enough Study participants indicated that they spent almost 9 hours a day sitting, some spending up to 16 hours in this position. In addition, they performed an average of between 80 and 160 minutes of moderate physical activity per week, and less than 135 minutes of vigorous exercise.
The researchers analyzed two key indicators of cardiac and metabolic aging: total cholesterol/HDL ratio and body mass index (BMI). They found that the more time spent sitting, the faster signs of aging appear and that doing a little moderate activity at the end of a day of long hours sitting does not seem to be enough to mitigate these effects.
“Our research suggests that it may be necessary to sit less during the day, exercise more vigorously, or a combination of both, to reduce the risk of premature aging.”
Thus, young adults who spent 8.5 hours sitting each day and met only the minimum exercise recommendations could fall into a “moderate to high risk” category for cardiovascular and metabolic diseases, according to the authors. “Taking a brisk walk after work may not be enough,” Reynolds said. “Although this becomes more evident with age, we show that these associations already begin to emerge in early adulthood.”
However, vigorous exercise did have a buffering effect. Those who engaged in vigorous exercise, such as running or cycling, for 30 minutes a day had similar cholesterol levels and BMIs as people 5 to 10 years younger who spent the same amount of time sitting but not exercising. However, the study concluded that even vigorous exercise cannot completely counteract the negative effects of sitting for long hours.
Twins with the same genes and different lifestyles
The study of identical twins is especially useful because they share 100% of their genes and this allows us to rule out genetic factors and focus on lifestyle differences. By analyzing twins with different sedentary and physical activity habits, researchers found that replacing sitting time with exercise was more effective at improving cholesterol levels than adding exercise to an excessively sedentary day.
In conclusion, researchers recommend doing both: reducing sitting time and increasing physical activity. Using a standing desk, taking breaks, and holding walking meetings can help reduce sedentary time at work. Whenever possible, get at least 30 minutes of vigorous daily activity or intense exercise sessions on the weekend, suggests Bruellman.
Bruellman hopes the study will serve as a wake-up call for health policy makers to review physical activity guidelines and specify how much sitting is too much. Meanwhile, Reynolds urges young adults to adopt medications now that could benefit their health in the future: “Now is the time to create habits that will benefit long-term health.”
