Scientists claim they have come up with the perfect blend of exercise and down time for a longer and healthier life.
While the general recommendation is 30 minutes of moderate to vigorous activity every day, all this good work can be undone if we spend too much time sitting down.
An international study led by Glasgow Caledonian University found that three minutes of moderate to high intensity exercise for every hour of seating could reduce the chance of an early death by as much as 30% from ‘all cause mortality’.
For those who balk at the thought of moving vigorously every hour, researchers say similar benefits can be had with 12 minutes of light exercise including housework or a relaxed stroll.
The four-year study, published in the British Journal of Sports Medicine, is the largest of its kind in the world, analysing data from six previous studies involving more than 130,000 adults in the UK, US and Sweden. The researchers accounted for BMI, age and pre-existing conditions.
Led by GCU Professor of Health Behaviour Dynamics Sebastien Chastin, researchers used activity monitors on participants and a technique called compositional analysis to study the effect on mortality rates of different combinations of activities including brisk walking or running, walking and sedentary behaviour.
Although the current recommendation to do 30 minutes per day of moderate to vigorous physical activity reduces the odds of an earlier death by up to 80%, this was only seen in those who sat for less than seven hours.
It did not reduce mortality risk for individuals who were very sedentary (over 11 to 12 hours per day), the researchers found.
The researchers also found that there were multiple combinations of activities associated with a 30% reduction in the odds of an early death.
Doing 55 minutes of exercise and four hours of light physical activity means you could safely spend 11 hours sitting down. Thirteen minutes of exercise, 5.5 hours of light physical activity would allow for 10.3 hours on the sofa or office chair and three minutes of exercise, 6 hours of light physical activity will let you sit down guilt free for 9.7 hours.
Prof Chastin said: “We are still told that the biggest amount of evidence is that we should do 30 minutes of exercise a day. What we need to do is balance the time we spend exercising with the time we spend sitting.
“We wanted to find out what the perfect cocktail of physical activity throughout a day was for maximum health in terms of the time spent sitting, exercising, just moving around, and sleeping, and how these all work together.
“Our new formula found that three minutes of moderate to vigorous exercise per hour of sitting will get the balance right and help you live a longer, healthier life.
“The leftover hours should be spent generally moving around as much as you can and getting a good night’s sleep.
“You can mix and match, depending on your schedule.
“Thirty minutes of physical activity per day or 150 hours a week is what is recommended but you still have the potential to undo all that good work if you sit too long.
“We do have some work to do in terms of the public message.”
Prof Chastin said it is not known if harms are caused by continuous sitting down or accumulitive periods. He said he often a standing desk and sets an alarm clock every 20 minutes if he is sitting down while working to remind him to walk around. The study suggests jobs where people spend more time walking or standing up could be the healthiest.
“It goes back to a very early piece of research on physical activity which was done by a Scot on the London buses where they compared the conductors and the drivers and the conductors had much better health outcomes.
“Essentially the idea is supporting the World Health Organisation guidelines that every movement counts.”
Co-author Keith Diaz, PhD, Assistant Professor of Behavioral Medicine at Columbia University Vagelos College of Physicians and Surgeons, added: “For decades, we’ve been telling people that the way to stay healthy is to get at least 30 minutes of exercise five days a week.
“But even if you’re one of the few adults who can stick to this advice, 30 minutes represents just 2% of your entire day.
“Is it really possible that our activity habits for just 2% of the day is all that matters when it comes to health?
“In other words, it is not as simple as checking off that ‘exercise’ box on your to-do list.
“A healthy movement profile requires more than 30 minutes of daily exercise. Moving around and not remaining sedentary all day also matters.
“Our study shows that there is no one-size-fits-all approach to physical activity, and we get to choose which combinations of activities we like best ones.
“It may be more important to mix a movement ‘cocktail’ that includes a healthy dose of exercise and light activity to take the place of sitting.”