Remember, light exercise is good for you too

Coach potatoes take heart. If getting healthy is one of your resolutions but making daily jaunts to the gym seems daunting, researchers have good news for you.

It turns out that even light activity, think about walking the dog or vacuuming the carpet, may be better for you than we used to think. Two recent mortality studies, performed by researchers at Harvard University and the renowned Karolinska Institute in Stockholm as the Chicago Tribune reported, found that the most active subjects had a 50 to 70 per cent decline in mortality compared with the least active, most sedentary participants.

“We were somewhat surprised by the strong association between light activity and mortality,” said Ing-Mari Dohrn, first author of the Swedish paper as the Tribune noted. “It was a strong factor for reductions in cancer and cardiovascular deaths, as well as for all-cause mortality.”

Diet and exercise studies have long bedevilled by issues of self-reporting, such as inaccuracy. Who can resist fudging a little about how much fudge they ate?

However, as the Washington Post points out, the situation has improved for exercise epidemiologists, because of the advent of lightweight, wearable accelerometers (hello Fitbit). These gadgets allow scientists to collect activity data — such as how much they sit, how much they move — on large numbers of people in a more objective manner.

The Harvard researchers mailed accelerometers to more than 16,000 U.S. women, who wore them for 15 hours a day on four or more days. The scientists then followed the women for an average of 2.3 years to determine their mortality data. The Swedish team, meanwhile, gave similar devices to 851 subjects, including almost 400 men, who wore them for 14 or more hours on four or more days. Those subjects were tracked for 14.2 years.

“What’s new and important is the strength of the association we discovered with the more precise measurements,” said I-Min Lee, an exercise epidemiologist on the Harvard team in the Post. “Our most active women had a 60 to 70 per cent decline in mortality, which compares favourably to the 50 per cent difference you would see between non-smokers and smokers. This is why the public should pay more attention to being physically active.”

Though working with different populations in different countries, both studies reported remarkably similar measurements for time sitting, time in light activity (time to fold the laundry), and time in moderate-to-vigorous activity (a game of hoops). Apparently Americans and Swedes both spend an average of about 500 minutes a day sitting, 350 minutes in light activity and 30 minutes in moderate to vigorous activity, as the Post reported.

In addition, the Swedish team also found that individuals who sit fewer than six hours a day have a 66 per cent lower mortality risk than those who sit more than 10 hours a day.

So get up from your computer and go find Fido for a whirl around the neighbourhood. Dare you. Or clean the house. Or play tag with your kid on the lawn. No matter how you move it may make a big difference in how long you live.