Here’s a question: what do they mean whey they say “moderate” exercise? And how about “vigorous” exercise? What does that mean? Writing in the New York Times, Gretchen Reynolds reports that Canadian guidelines state that during moderate exercise,”your pulse should rise to about 64 percent to 76 percent of your maximum heart rate and during vigorous exercise, your pulse should hover between about 77 percent and 90 percent of your maximum.” Too complicated? Reynolds tells us that 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.” Much better. And now the news: Reynolds reports on a recent study showing that “many of us underestimate how hard we should exercise to achieve maximum health benefits, and overestimate how vigorously we are actually working out.” The study, which involved 129 sedentary adult Canadians ages 18 to 64, measured the heart rates of people as they exercised at levels that they considered to be moderate and vigorous. How close were they? Not very. Reynolds reports that few exercisers maintained a heart rate above 65 percent of their maximum when they were supposedly exercising moderately and even fewer reached a heart rate above 75 percent of maximum during their version of vigorous exercise. Wait, there’s more: “a majority of the volunteers walked at a decidedly languorous pace when asked to estimate the lowest-intensity exercise that would qualify as moderate and provide robust health benefits. Only about 25 percent reached a pace that raised their heart rate into the moderate range. The rest gently strolled.” Read more in the New York Times.