The American College of Sports Medicine recommends that individuals achieve at least 150 minutes of moderate-intensity exercise per week. Duration can be shorter if the intensity is vigorous. However, a recent report from York University’s School of Health in Toronto suggests that many people think they are exercising more intensely than they actually are.
The study involved 129 inactive adults aged 18–64 who received guidelines and descriptors on exercise intensity. Participants then walked or jogged on a treadmill at what they considered light, moderate and vigorous paces, in random order, according to their perceptions of the guidelines. Heart rates were recorded via heart rate monitor, and study authors took note of the self-selected treadmill speeds. Participants also completed VO2 peak exercise tests.
Data showed that in most cases subjects exercised below the intensity guidelines.
“Participants accurately estimated light effort physical activity and underestimated moderate and vigorous effort physical activity, and there appears to be no differences by sex, ethnicity or across BMI classifications,” explained the authors, who added that middle-aged individuals tended to discern intensity levels more accurately than younger participants.
The data caused concern among study authors, who posited that many more individuals are falling short of activity recommendations than previously thought. The authors suggested that the descriptors used to explain intensity levels could be part of the problem. “Given the difficulties in understanding moderate and vigorous effort physical activity, new subjective descriptions for moderate and vigorous intensity may be warranted to aid individuals with the understanding of physical activity intensity,” they concluded.
The study was published in PLOS ONE (2014; doi: 10.1371/ journal.pone.0097927).