Is Yoga Enough to Keep You Fit?

We sent three yogis to the lab to test the theory that yoga is all you need for optimal fitness.

By Alisa Bauman

Physiologists can measure body composition in several ways. The simplest method uses a pair of calipers to pinch the skin and underlying fat at various spots on the body. This method works best for athletes and others with little visible body fat. For those with more body fat, a more accurate method is hydrostatic weighing—being weighed while submerged in water and comparing the result to your out-of-water weight. Because fat floats, the greater the difference between your submerged and dry weights, the higher your body fat percentage.

Experts have long recommended that we do at least three different types of activity to achieve optimum cardiorespiratory and muscular fitness, flexibility, and body composition. For example, the ACSM recommends building cardiorespiratory fitness by exercising at an intensity that raises your heart rate to at least 55 percent of your maximum heart rate (the highest rate you can maintain during all-out effort, generally estimated as 220 minus your age); muscular fitness by targeting each major muscle group with eight to 12 repetitions of weight-bearing exercise; and flexibility by stretching.

No one argues against yoga's ability to satisfy the flexibility requirement. But until recently, few scientists had considered whether yoga could improve other aspects of fitness. Now that's starting to change.

Putting Yoga to the Test
In one of the first studies done in the United States that examines the relationship between yoga and fitness, researchers at the University of California at Davis recently tested the muscular strength and endurance, flexibility, cardiorespiratory fitness, body composition, and lung function of 10 college students before and after eight weeks of yoga training. Each week, the students attended four sessions that included 10 minutes of pranayama, 15 minutes of warm-up exercises, 50 minutes of asanas, and 10 minutes of meditation.

After eight weeks, the students' muscular strength had increased by as much as 31 percent, muscular endurance by 57 percent, flexibility by as much as 188 percent, and VO2max by 7 percent—a very respectable increase, given the brevity of the experiment. Study coauthor Ezra A. Amsterdam, M.D., suspects that VO2max might have increased more had the study lasted longer than eight weeks. In fact, the ACSM recommends that exercise research last a minimum of 15 to 20 weeks, because it usually takes that long to see VO2max improvements.

"It was very surprising that we saw these changes in VO2max in such a short time," says Amsterdam, professor of internal medicine (cardiology) and director of the coronary care unit at the U. C. Davis Medical Center in Sacramento. He is now considering a longer, larger study to authenticate these results.

A related study done at Ball State University offers further evidence for yoga's fitness benefits. This research looked at how 15 weeks of twice-weekly yoga classes affected the lung capacity of 287 college students. All of the students involved, including athletes, asthmatics, and smokers, significantly improved lung capacity by the end of the semester.

Page 1 2 3 4 5 6

See All Asana Columns Articles »