Effects of Temperature and Tempo: Evaluating How Much Time in a Typical Community-Based Yoga Class Is Moderate-Intensity Aerobic Activity

The 2nd edition of the Physical Activity Guidelines for Americans (PAG) recommends, in part, 150 min of moderate-intensity aerobic physical activity. The PAG states that yoga may be able to help meet the guidelines for moderate-intensity aerobic exercise for adults and older adults. Our study aims to objectively measure the proportion of time participants’ activity that is categorized as moderate-intensity aerobic activity based on heart rate data and to subjectively measure rate of perceived exertion (RPE). Participants completed the Stanford Leisure-Time Activity Categorical item to establish baseline PAG aerobic activity compliance. Participants then completed four separate 1-h yoga sessions at different tempos (cadence) and temperatures while wearing heart rate monitors. During and directly after the session they also marked their RPE on a modified 10-point scale. All participants reached moderate-intensity aerobic activity for at least some portion of a yoga session based on heart rate monitor data and RPE. The average duration of moderate intensity was 32.75% of the class across all four class types, with no significant differences by condition. Age was a significant factor in time spent in moderate-to-vigorous physical activity for only the thermo-neutral Hatha classes (p = 0.010). Tempo, temperature, and baseline activity levels were not significant factors in time spent in moderate-to-vigorous intensity physical activity based on Pearson Correlation and the Kruskal–Wallis test. Hatha and Vinyasa yoga classes, at room or hot temperatures, can be used to meet a portion of the PAG moderate-intensity activity recommendations.