Stand up before you read this.
Sitting for most of the day can prompt the same physical changes that increase the risk of developing chronic diseases like cancer, heart disease, and diabetes, cancer experts said at an American Institute for Cancer Research conference in Washington on Thursday.
More than 100,000 cancer cases in America this year could have been prevented if people exercised more, including more than 48,000 breast cancer cases and 42,000 colon cancer cases, experts said at the conference. The American Cancer Society projects nearly 1.6 million Americans will be diagnosed with cancer this year and more than 570,000 will die of it.
Epidemiologist Christine Friedenreich of Alberta Health Services-Cancer Care in Calgary, Canada, said the numbers linking exercise to lower cancer risk come from a variety of studies. For instance, people who exercise the most have a 30 to 35 percent lower risk of colon cancer compared to those who exercise the least, and highly active people have a 20 to 30 percent lower risk of breast cancer, she said.
“The world in which we live is designed to make us sit, and we did not evolve in an environment that had lounge chairs,” said Neville Owen of the Baker IDI Heart and Diabetes Institute in Melbourne, Australia. “And we can do a lot about it, but there’s a lot of public policy change we need to make.”
It’s not just about sending kids to soccer practice, said Lawrence Soler, president and CEO of Partnership for a Healthier America. “There are many other things we can have our kids do,” Soler said, like encouraging "instant recess" and breaks in the school day.
After years of celebrating sitting still as a virtue in schoolchildren, it might be time to let kids out of their seats, AICR says. Nearly one-third of American children are overweight or obese, Soler noted.
The new research may also have implications for public health initiatives like first lady Michelle Obama’s Let’s Move! campaign, which aims to reduce childhood obesity.
Studies suggest that obesity may cause up to a third of all cancer cases; it hasn’t been clear just what it is about obesity that can cause cancer, but many studies show exercise reduces the inflammatory processes in the cells.
Friedenreich said her recent research shows exercise lowers levels of C-reactive protein, a so-called marker of inflammation.
To reflect the new research, AICR has expanded its physical activity guidelines to recommend that people take short, 1-2 minute breaks throughout the day, as well as 30 minutes of moderate to vigorous exercise every day, to reduce the risk of cancer.
Even people who consider themselves active can still be sitting down for more than two-thirds of their day, Owen said. “Even when you control for the total sitting time, breaking it up is related to a lower waist circumference, and it’s related to other biomarkers that are important in other chronic diseases.” Restless people who are constantly getting up and moving around can have waistlines two inches smaller than those spend a lot of time sitting still, he said.