THE ESSENTIAL
- Young adults who sit for a long time and don’t get enough physical activity are at “moderate to high risk” of cardiovascular and metabolic diseases, as well as aging.
- Adding a little moderate activity to a long day of sitting does not alleviate these effects.
- In contrast, more intense activity can counter the health effects of sitting, but with “diminishing returns.”
“Young adults tend to think that they are immune to the effects of aging. They tell themselves that their metabolism is good and that they don’t have to worry until they are in their 50s or 60s. But What you do during this critical period of life matters,” said Ryan Bruellman, who works in the department of genetics, genomics and bioinformatics at the University of California, Riverside (United States). Indeed, the sedentary lifestyle of Millennials speeds up their biological clock.
The more we sit, the older we get and the risk of developing heart disease.
To reach this conclusion, the researcher and his colleagues carried out research during which they analyzed data from a cohort of 1,000 current or former residents of Colorado, including 730 twins, aged 28 to 49 years old. “Monozygous, i.e. ‘real’ or ‘identical’ twins are particularly useful to study because they share 100% of their genes, making it easier to rule out genetic factors that may contribute to different health outcomes and focus on lifestyle differences.” After asking participants to complete a questionnaire, the authors looked at two key measures of cardiac and metabolic aging: total cholesterol/high-density lipoprotein and body mass index (BMI).
On average, volunteers reported sitting for almost 9 hours a day, with some remaining seated for up to 16 hours. They reported an average of 80 to 160 minutes of moderate physical activity per week and less than 135 minutes of vigorous exercise per week. According to the results, published in the journal Plos Oneprolonged sitting accelerates aging. Young adults who sit 8.5 hours a day and whose physical activities are less than or equal to current recommendations could fall into a “moderate to high risk” category for cardiovascular and metabolic diseases.
Sedentary lifestyle: “taking a quick walk after work may not be enough”
“Taking a quick walk after work may not be enough. Although this becomes increasingly evident with age, we show that associations appear already in early adulthood,” said Chandra Reynolds, lead author of the work. On the other hand, practicing intense physical activity has a slight buffering effect. For example, people who cycled or ran for 30 minutes a day had cholesterol levels and body mass index comparable to individuals five to ten years younger who sat as much as them but didn’t exercise. However, the “yields” are “decreasing”.
In the findings, the researchers advise sitting less time during the day, doing more physical exercise, or a combination of the two, to reduce the risk of premature aging. “Use a standing desk, take breaks, and hold meetings while walking to reduce the time you spend sitting at work. If possible, do something that gets you out of breath for at least 30 minutes a day, or be a weekend exerciser by doing longer, more intense workouts when you can (…) Now is the time to form habits that will benefit long-term health.”
