What the studies show about Ashtanga Yoga, from the heart to the bones

Anyone who walks into an Ashtanga Yoga room finds a fixed sequence of postures, linked by the breath and performed at a pace that leaves the shirt soaked. The question is what, concretely, science can say about that effort. The answer, after gathering the available studies, is a modest one: there are real, consistent benefits, almost all measured in small groups over a few months.

Ashtanga is a dynamic style of yoga, sometimes classified as a form of Vinyasa. What the research indicates for the body, the mind and a few biological markers, and how the practice fares against other kinds of exercise, is what matters here.

Strength, flexibility and balance

The most cited study is Cowen and Adams, from 2005. Twenty-six healthy adults, aged 20 to 58, were split into two groups, one doing Ashtanga and the other Hatha Yoga, a slower style. Over six weeks, both gained trunk strength and flexibility. The Ashtanga group went further: it gained upper-body strength, greater flexibility, and reported an improved perception of its own health.

In a 2007 study, Gruber followed twelve young women for three months. Those who practiced Ashtanga increased arm muscular endurance and trunk flexibility and reported less stress than the control group. The study is an academic dissertation, not a journal article, and the group is tiny.

On balance, the evidence comes from yoga in general. College athletes who did ten weeks of yoga improved on a one-leg balance test. In elite fencers, eight weeks of yoga or Pilates produced equivalent gains in stability and mobility.

Heart, lungs and bones

Ashtanga is a moderate-intensity exercise. Measurements cited in the literature show that a short sun-salutation sequence, around twelve minutes, already pushes the pulse to near 80% of maximum. The caloric cost of a full class is close to that of a brisk walk. In Cowen and Adams's study, only the Ashtanga group had a significant drop in systolic blood pressure. For anyone seeking high cardiovascular performance, running and cycling remain superior.

For bones, the result is mixed. Kim and colleagues followed 34 premenopausal women for eight months. In those who practiced Ashtanga, a marker of bone formation stayed stable, with a slight rise of about 9%, while it fell about 7% in the sedentary group. Bone mineral density, however, did not change in either group. The practice appears to slow a decline rather than build new bone, unlike what weight training typically does.

Stress, mood and the brain

It is in the emotional domain that the data are most abundant. In an intervention study by Jarry and colleagues, 44 adults took Ashtanga classes twice a week for nine weeks. The 31 who completed it reported fewer symptoms of depression and anxiety, more positive affect and higher self-esteem. They also said they felt more assertive and more connected to others. There was no comparison group, and that limitation weighs on the reading.

A brain-imaging study by van Aalst and colleagues, in 2020, compared ten experienced practitioners, with at least two years of practice, to fifteen people without that experience. At rest, the practitioners had lower glucose consumption in regions tied to emotion and stress, such as the hippocampus and the amygdala, somewhere between 5% and 8% lower. The difference grew with years of practice. The study cannot say that yoga caused the change, only that the two things appear together.

There are also signs of lower cortisol, the stress hormone, and improved cholesterol and triglycerides in yoga programs in general. There is no Ashtanga-specific data on inflammation or on the neurotrophic factor BDNF, linked to brain plasticity.

Against other practices

Compared with walking, Ashtanga ties in moderate effort and wins by including strength and stretching. Against weight training, it loses on muscle mass and maximum strength gains and on bone stimulus, but offers more flexibility and balance. Against Pilates, the functional results are similar, and yoga tends to have the edge in joint range of motion.

Among yoga styles, a review of 306 studies concluded that the health benefit depends little on the style. Gentler styles may relax more in the moment, and vigorous ones demand more from the heart. Compared with meditation done alone, Ashtanga combines attention on the breath and gaze point with body movement, but someone who cannot exercise can still get stress relief from meditation alone.

What is still unknown

The studies gathered have samples of 10 to 44 people, last from six weeks to eight months, and do not always include a control group. Longer, larger studies are missing, especially on inflammation, cognition and immunity. For now, what can be said with confidence is modest and useful: Ashtanga strengthens, stretches, calms and works the heart at moderate intensity. It does not replace weight training for the bones or running for stamina, and it works best for whoever shows up again the following week.