Most of us know that moderate exercise is good for us. But surprisingly few of us know what moderate exercise means, research shows. A new study found that many of us underestimate how hard we should exercise to achieve maximum health benefits, and overestimate how vigorously we are actually working out.
It’s been six years since the federal government in the United States published exercise guidelines for adults. Straightforward and flexible, they recommend that adults complete 150 minutes of moderate or 75 minutes of vigorous aerobic exercise each week. Either prolonged sessions or multiple, shorter workouts are OK, and the form is never specified.
Since then, the governments of many other nations, including Canada and Britain, have endorsed essentially the same guidelines for their citizens, and doctors now routinely advise their out-of-shape patients to begin exercising moderately.
But no scientific studies had determined whether average people know what the recommended intensities feel like in action. So for a study published last month in PLOS One, researchers at York University in Toronto recruited 129 sedentary adult Canadians aged 18 to 64 and set out to see what they knew about exercising for health.
The formal exercise guidelines do offer guidance for determining the intensity of your workout. You can use heart rate, for instance. During moderate exercise, according to the Canadian guidelines, your pulse should rise to about 64 per cent to 76 per cent of your maximum heart rate; during vigorous exercise, your pulse should hover between about 77 per cent and 90 per cent of your maximum. More casually, the American guidelines suggest that during moderate exercise, you should be able to “talk, but not sing”, while during vigorous activity, “you will not be able to say more than a few words without pausing for a breath.”
The Canadian researchers began by asking volunteers if they were familiar with the national exercise guidelines. A few said they were, although most were not. So the researchers handed out copies of the guidelines for them to study, and then asked if they felt that they understood the guidelines.
With surprisingly little demur, almost all of the volunteers said that the guidelines were clear and they felt confident that they could complete the requisite amounts of moderate exercise. Quite a few of the volunteers said that they believed that they indeed were already meeting the guidelines.
The scientists then measured the volunteers’ actual maximum heart rate with a