Has there been any research on Restorative yoga?

Yes!  The first randomized trial (or high-quality experiment) on yoga was published in 1975 in The Lancet. It showed that yoga was effective for reducing high blood pressure. But that trial only involved 34 participants, and all of them already had high blood pressure, so it is difficult to know whether the effect of the yoga would bear out in a larger trial of healthy people.

Since then, the number of yoga studies has dramatically increased, but the field is plagued by some of the same problems of that early study. Many yoga studies still involve small numbers of participants. Many lack a control group.  What studies do exist are often short term. 

Still, the quality and quantity of studies has been improving, so we may get better answers soon. "There are more researchers conducting yoga therapy studies, and when the smaller trials suggest benefit, that leads to larger, better-designed trials," said Lorenzo Cohen, chief of the integrative medicine section at MD Anderson Cancer Center.

There is also a move to study the biological outcomes of yoga — how practicing yoga affects things like hormone levels — which will lead us to a more objective picture of what yoga can do for the body.

What have scientists learned about Restorative yoga, so far?

Scientists don't fully understand why the practice makes people feel not just rested but reborn. However, a growing body of evidence suggests it has measurable health benefits. Roger Cole, PhD contributed to one study that showed a six-point-greater drop in blood sugar in a group of prediabetics who practiced restorative yoga (at least 30 minutes three times a week for a year) compared with those who did stretching exercises. There's more: The restorative yoga students lost two pounds more than the stretchers, along with nearly a half-inch more from their waistlines. "We were surprised by the weight loss," says lead study author Alka Kanaya, MD. It made researchers think that another mechanism that they weren't able to measure—possibly more mindfulness, relaxation, or better sleep—might be at play," Kanaya says.

Studies also suggest that restorative yoga can decrease hot flashes during menopause, as well as reduce fatigue and boost quality of life in women with breast cancer. "Long-term practice can also become a buffer to chronic stress," says Aditi Nerurkar, MD, an integrative medicine physician who teaches at Harvard Medical School. 

Clinically documented benefits of Restorative yoga include:

• Improved posture, circulation, blood pressure, and lower cholesterol levels.

• It is good for alleviating back, hip, and neck pain.

• It also improves cardiovascular and respiratory function.

• In addition, it can help boost the immune system.

• It calms the nervous system by stimulating the parasympathetic nervous system, which slows down heart rate and breath. This reduces the fight or flight response.

• Certain positions can also help improve digestion and constipation by massaging the organs.

• Furthermore, Restorative yoga can decrease inflammation within the body and increase blood flow.