New research by Columbia University exercise physiologists suggests that prolonged sitting — a staple of modern-day life — is hazardous to your health, even if you exercise regularly. Based on these findings, doctors advise all adults to sit less and move more.
Few studies have researched: What is the least amount of activity needed to counteract the health impact of a workday filled with sitting?
The answer according to this new study? Just five minutes of walking every half hour during periods of prolonged sitting can offset some of the most harmful effects.
The study, led by Keith Diaz, PhD, was published online in Medicine & Science in Sports & Exercise, the journal of the American College of Sports Medicine.
Unlike other studies that test one or two activity options, Diaz’s study tested five different exercise “snacks”: one minute of walking after every 30 minutes of sitting, one minute after 60 minutes; five minutes every 30; five minutes every 60; and no walking.
“If we hadn’t compared multiple options and varied the frequency and duration of the exercise, we would have only been able to provide people with our best guesses of the optimal routine,” Diaz says.
Each of the 11 adults who participated in the study came to Diaz’s laboratory, where participants sat in an ergonomic chair for eight hours, rising only for their prescribed exercise snack of treadmill walking or a bathroom break. Researchers kept an eye on each participant to ensure they did not over- or under-exercise and periodically measured the participants’ blood pressure and blood sugar (key indicators of cardiovascular health). Participants were allowed to work on a laptop, read, and use their phones during the sessions and were provided standardized meals.
The optimal amount of movement, the researchers found, was five minutes of walking every 30 minutes. This was the only amount that significantly lowered both blood sugar and blood pressure. In addition, this walking regimen had a dramatic effect on how the participants responded to large meals, reducing blood sugar spikes by 58% compared with sitting all day.
Taking a walking break every 30 minutes for one minute also provided modest benefits for blood sugar levels throughout the day, while walking every 60 minutes (either for one minute or five minutes) provided no benefit.
All amounts of walking significantly reduced blood pressure by 4 to 5 mmHg compared with sitting all day. “This is a sizeable decrease, comparable to the reduction you would expect from exercising daily for six months,” says Diaz.
The researchers also periodically measured participants’ levels of mood, fatigue, and cognitive performance during the testing. All walking regimens, except walking one minute every hour, led to significant decreases in fatigue and significant improvements in mood. None of the walking regimens influenced cognition.
“The effects on mood and fatigue are important,” Diaz says. “People tend to repeat behaviors that make them feel good and that are enjoyable.”
The Columbia researchers are currently testing 25 different doses of walking on health outcomes and testing a wider variety of people: Participants in the current study were in their 40s, 50s, and 60s, and most did not have diabetes or high blood pressure.
“What we know now is that for optimal health, you need to move regularly at work, in addition to a daily exercise routine,” says Diaz. “While that may sound impractical, our findings show that even small amounts of walking spread through the work day can significantly lower your risk of heart disease and other chronic illnesses.”
Previous research from the University of Sydney examined the associations of sitting and physical activity with premature death and cardiovascular disease mortality, and estimated what level of moderate to vigorous intensity physical activity, such as swimming, might offset health risks of sitting. The study’s key message is that physical activity is particularly important for people who sit a lot and that meeting the Australian public health recommendation of 150 to 300 minutes per week – equivalent to around 20-40 minutes per day on average – appeared to eliminate sitting risks.
Replacing sitting with physical activity – but not standing – reduced mortality risk among ‘high sitters’, people who sit over six hours per day, said lead author Professor Emmanuel Stamatakis, from the University of Sydney’s Charles Perkins Centre and Prevention Research Collaboration in the School of Public Health.
“In our study, sitting time was associated consistently with both overall premature mortality and cardiovascular disease mortality in the least physically active groups – those doing under 150 minutes of moderate to vigorous intensity physical activity per week,” Professor Stamatakis says.
“For example, people who were physically inactive and sat for more than eight hours per day had 107 per cent higher risk for cardiovascular death compared to those who did at least one hour physical activity per day and sat less than four hours.”
Physical activity doses equivalent to meeting the basic current recommendations –at least 150 minutes of moderate intensity or 75 minutes of vigorous intensity activity per week – were found to reduce or effectively eliminate associations between sitting and both cardiovascular and overall mortality risk. “Any movement is good for health but physical activity of moderate to vigorous intensity – that is activities that get people out of breath– is the most potent and most time-efficient,” Professor Stamatakis says. “Exercise and sports are a great way to be active but are not the only way – walking fast, climbing stairs, and cycling to get from place to place are only some of the many opportunities everyday life offers to move and even ‘huff and puff’ sometimes.”
Swimming is also a great way to get moving with minimal impact on your body – think pool aerobics. Consider these five surprising benefits of swimming and boost your mental and physical wellbeing.