Is yoga sufficient strength exercise for optimal health, or do I have to lift weights in a fitness center?
In general, the few available experiments involving yoga suggest that it leads to measurable but limited and patchy strength gains.
Consider the results of a 2012 study of premenopausal women who were randomly assigned to yoga or to a control group. The yoga group completed twice-weekly, 60-minute sessions of Ashtanga yoga (which consists of sequential, standardized postures), while the control group continued their normal activities. After eight months, the yoga practitioners had developed more powerful legs compared with at the study’s start and with those of the control group, but had not increased strength in other muscles or improved their cardiovascular fitness.
Similarly, in a 2013 study, 12 weeks of Bikram yoga (a variety that consists of other, specific poses done rapidly in a heated, saunalike space), enabled a group of young adults to dead-lift more weight on a barbell than they could at the start, but did not improve their hand-grip strength or any other measures of health and fitness.
Over all, yoga appears to be too gentle physically to be anyone’s lone exercise. In one of the most interesting studies of the activity to date, experienced yoga enthusiasts performed their favorite type of yoga for an hour in a metabolic chamber that tracked their caloric usage and heart rate. The volunteers then sat quietly in the chamber and also walked on a treadmill there at a leisurely 2 miles per hour and a brisker 3 m.p.h. pace. In the end, the measurements showed that yoga was equivalent in energy cost to strolling at 2 m.p.h., an intensity of exercise that, the authors write, would “not meet recommendations for levels of physical activity for improving or maintaining health or cardiovascular fitness.” Continue reading >>