Sitting for hours may raise cancer risk, but 3 minutes of vigorous movement could help; why short bursts of activity matter

Movement = reduced cancer risks

Is standing better than sitting?

Less sitting is the way forward

You do you

How much time do you spend sitting each day? Five hours? Six, maybe eight or more? If your answer is ‘too long’, know that you are not alone. Most of us sit for long hours. Though we know prolonged sitting is slowly killing us, less was clear about what happens when we stand up, take a walk, or sprint up a stairwell instead. A new study published in July in BMC Medicine is the first to examine how replacing sitting time with almost any kind of activity improves health. And guess what they found? Replacing just three minutes of sitting with vigorous movement, such as jogging up and down the stairs or running to catch a bus, is linked to a reduced risk of at least 13 types of cancer.How we move and don’t move during the day has a lot to do with how well you feel later. For instance, if you spend most of your day sitting, try jogging up and down the stairs for three minutes, or stand up from your desk or couch for 30 minutes. Both are associated with a reduced risk of certain cancers by about 7%, the new study suggests.The researchers looked at extensive activity data from nearly 60,000 adults, using statistical models to determine which movements – standing, strolling, rushing around the block – were strongly associated with fewer cancer cases, including breast, colorectal and lung cancers.“The reassuring finding is that every movement contributed,” John J. Mitchell, a senior research fellow at University College London’s Institute of Sport, Exercise & Health, and the study’s lead author, said, as reported by the Washington Post. However, not all movements were the same.“Some choices proved more beneficial than others,” Mitchell said.On average, American adults spend nearly 10 hours a day sitting, according to studies . A sedentary lifestyle, especially prolonged sitting commonly seen in IT and other desk jobs, is linked to several diseases, such as heart disease, type 2 diabetes, obesity and other conditions. Studies have also shown that prolonged sitting increases the risk of cancer Movement may help. But does standing up count? Or do you have to really walk? Or simply raise your heart rate? Perhaps sweating it out may help? These questions really matter because most young adults spend their time at their desks. So what can be done realistically to reduce the time spent seated? The idea is to bring down the time you are glued to your seat.Previous studies have largely focused on one change: standing more often. They, however, didn’t reveal if standing for some time would undo the effects of prolonged sitting compared with climbing stairs.The new study looked at data from the UK Biobank health study of 59,218 adult men and women, who wore a specialised activity tracker for a week. Researchers at University College London used machine learning to classify their movements across a full day: sitting, standing, gentle strolls and breathless rushes, such as trying to catch a bus.They also looked at the medical records of these people for eight years after they joined the Biobank to understand if they developed any of the 13 cancers linked to inactivity.What the researchers found was striking. Replacing 15 minutes of sedentary behaviour with 15 minutes of movement was linked to a 2% reduced cancer risk. This is good, though not transformative. They also checked if standing helps. And guess what? It does.Compared with prolonged sitting, standing up for any period of time was linked to a reduced risk of cancer. Standing was half as good as moving. Any type of movement may help: short walks, gentle strolls or walking for 15 minutes was linked to a reduced cancer risk. This 15 minutes was equal to half an hour of standing. So yes, standing helps.Vigorous activity, however, worked on a different scale altogether. Three minutes of daily vigorous activity was associated with a similar reduction in cancer risk as 90 minutes of light-intensity movement.While most of us know that sitting is quietly killing us, for some, it is unavoidable. So the trick really is to curate what works for you. According to Emmanuel Stamatakis, a professor of physical activity and health at Monash University in Australia, and senior author of the new study, there can be ‘different routes’ to the same goal. Which means, if you can’t really get 90 minutes to walk around the block, you can climb the stairs instead. Jog up and down the stairs for three minutes; that would do. That's you doing intense exercise, which is linked to reduced risk of cancer.“It is really encouraging that adding movement or standing is associated with reduced risk of cancer. But what stuck out for me was the finding that ‘only three minutes of additional vigorous physical activity in place of any other intensity was associated with lower cancer risk’,” Lora Giangregorio, an exercise scientist at the University of Waterloo in Canada, said.In fact, you do not have to be obsessed with a certain physical activity. Any movement counts, the authors said. So if you have a desk job and you cannot leave every now and then, ensure that you are squeezing some standing time into it. While you take calls, walk around the block. Refill your water bottles often. All these can help.