Sitting is sometimes described as the 'new smoking' due to its impact on people's health, but the big question is how much exercise we need to offset its effects.
The effects of sitting for long periods – as many of us do – are serious, with a 2011 study linking extended periods of sitting to a 49% increased risk of death.
But there’s good news from a new Columbia University study, which finds that just five minutes of walking every half hour can offset some of the worst effects.
The study, led by Keith Diaz, PhD, associate professor of behavioural medicine at Columbia University tested five different exercise "snacks", which were: 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.
Diaz says, "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.”
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 measured the participants' blood pressure and blood sugar (key indicators of cardiovascular health).
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.
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.
Walking every 60 minutes – either for one minute or five minutes – provided no benefit.
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.
"The effects on mood and fatigue are important," Diaz says. "People tend to repeat behaviours 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:
"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."
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