The research focused on participants between the ages of 28 and 49, with an average age of 33. On average, these individuals reported sitting almost nine hours daily, with some participants sitting up to 16 hours. They averaged between 80 and 160 minutes of moderate physical activity weekly and less than 135 minutes of vigorous exercise – numbers that researchers believe are actually better than national averages due to Colorado’s active lifestyle.
The study measured two key indicators of cardiovascular and metabolic health: Body Mass Index (BMI) and the ratio of total cholesterol to high-density lipoprotein cholesterol (TC/HDL), also known as the Cardiac Risk Ratio. These measurements provide important insights into heart health and metabolic function, with higher numbers generally indicating increased health risks.
The findings were striking: those who sat for longer periods showed higher TC/HDL ratios and BMIs, even when meeting the minimum recommended physical activity guidelines of about 20 minutes per day of moderate exercise. Simply put, the more someone sat, the “older” their body appeared in terms of these health markers.
However, the research did identify one potential buffer against the effects of prolonged sitting: vigorous exercise. Participants who engaged in 30 minutes of vigorous daily activity – such as running or intense cycling – showed health markers similar to those of people five to 10 years younger who sat the same amount but didn’t exercise vigorously. Yet even this level of intense activity couldn’t completely neutralize the negative impacts of extended sitting.
The study’s use of twin participants proved particularly valuable in understanding these relationships. Because identical twins share 100% of their genes, comparing twins with different activity levels allowed researchers to isolate the specific effects of lifestyle choices on health outcomes. When examining twins with different sitting and exercise habits, the researchers discovered that replacing sitting time with exercise appeared more beneficial for cholesterol levels than simply adding exercise to a day full of sitting.
“Our research suggests that sitting less throughout the day, getting more vigorous exercise, or a combination of both may be necessary to reduce the risk of premature aging in early adulthood,” says senior author Chandra Reynolds, a professor in the Department of Psychology and Neuroscience and the Institute for Behavioral Genetics.
What exactly counts as “vigorous” exercise? Activities that really get your heart pumping – think running, fast cycling, high-intensity interval training, or vigorous swimming. These activities typically require more effort than moderate exercises like brisk walking or casual cycling.
The findings serve as a crucial wake-up call for young adults and suggest that current physical activity guidelines may need revision to account for our increasingly sedentary lifestyles. As Reynolds advises, “This is the time to build habits that will benefit health over the long term.”
Source: https://studyfinds.org/millennials-sitting-biological-clock/