Want to stay healthy? Reduce sitting time by 21 minutes

It is a known fact that prolonged sedentary time poses serious threats to our health. But what can we do about it? A new study investigates.

In our modern daily life, office-based work has become more and more prevalent, and we spend an increasing amount of time being entertained by streaming services and social media.

This results in many of us spending too much time sitting down - in fact, a recent survey has shown that people in the United States spend an average of 13 hours per day being sedentary.

But too much time sitting down can be hazardous to our health. Prolonged sitting has been shown to raise the risk of type 2 diabetes, heart disease, and premature death.

However, insufficient research has explored whether or not reducing sedentary time is actually possible given the demands of our modern lifestyle, and whether such a reduction brings any health benefits for people who are already in good health.

This is why researchers from the University of Jyväskylä in Finland set out to examine the impact of reducing sedentary time over a period of 1 year.

The first and corresponding author of the study is Dr. Arto Pesola, of the university's Neuromuscular Research Center in the Faculty of Sport and Health Sciences, and the findings were published in the journal PLOS One.

Is reducing sedentary time possible?

Dr. Pesola and team conducted a "cluster-randomized trial," meaning that 133 participants with young children were randomly separated into two groups: 71 participants were assigned to the intervention group and 62 joined the control group.

The participants in the intervention group were asked to participate in a 30-minute lecture on the dangers that prolonged sedentary time poses to health, the challenges of modern life that encourage excessive sitting, and strategies for reducing sedentary time.

Then, they were offered one-to-one, face-to-face counseling sessions during which they discussed tailored approaches for reducing sedentary time both at work and in their free time.

In these sessions, participants set "contractually binding goals" to decrease sitting time and increase light physical activity.

The most popular goals for the workplace were to break up sedentary periods, and for leisure, participants most commonly wished to increase the time they spent with their family while being physically active.

Additionally, participants generally wanted to increase light physical activity during their commute - for example, by parking the car farther away from work so as to walk more.

The researchers evaluated whether the participants hit their goals by asking them to wear an accelerometer around their waists for five 1-week segments between April 2011 and April 2012.

Dr. Pesola and team took anthropometric measurements such as body mass index (BMI), weight, body fat composition, and blood pressure at baseline and every 3 months until the completion of the study. They also took blood samples testing for biomarkers of cardiovascular and metabolic health.

Just 21 minutes less sitting improves health

The study showed that reducing sitting time both at work and during leisure time was, in fact, possible. At baseline, participants spent around 5.6 hours at work sitting down and 3.8 hours during their leisure time.

However, after the counseling sessions, intervention participants decreased the leisure time they spent sitting down every day by 21 minutes and increased their light-intensity physical activity and the number of breaks in-between sitting time.

Additionally, the study found that women managed to increase both light physical activity and the number of sitting breaks in the workplace. Men, on the other hand, were not able to do so.

Fasting blood sugar levels - which is a measurement commonly used to check for prediabetes and diabetes - was found to be slightly lower after the counseling. Also, a biomarker of cholesterol and cardiovascular disease called Apolipoprotein B-to-Apolipoprotein A-1 ratio was found to improve over the year.

Furthermore, participants in the intervention group maintained leg muscle mass, whereas those in the control group lost 0.5 percent more muscle mass.

"This study shows that it is possible to reduce the sedentary time of people in a busy phase of life. [...] This is important, because sedentary time tends to increase while we age. The effect was most visible during leisure time, where the sedentary time was already lower."

Dr. Arto Pesola

"This may reflect the demands of working life and that counseling targeted at individuals and their families is ineffective in changing the sitting time at work, at least in men," he adds. "Instead, people may find more opportunities and freedom to reduce sedentary time and to participate in enjoyable family activities out of working hours."

Reducing sitting time by just 21 minutes "may be beneficial for health in the long run," concludes Dr. Pesola.