The study, of 123 middle-aged and older adults, found that those who added yoga classes to standard diabetes care shed some pounds over three months. Meanwhile, their average blood sugar levels held steady - in contrast to a non-yoga control group, whose blood sugar levels rose.
The findings, reported in Diabetes Care, do not suggest that yoga should replace other forms of exercise for people with type 2 diabetes.
To really lose weight and control blood sugar, more vigorous exercise would work better, according to Dr Shreelaxmi V. Hegde of the Srinivas Institute of Medical Science and Research Center in Mangalore, India.
Among the 60 study participants who took yoga classes several times a week, the average body mass index declined from 25.9 to 25.4.
"In our study the effect of yoga on BMI and blood sugar control was marginal," Dr Hegde, the lead researcher on the work, said.
"But," she added, "it should be noted that yoga controlled the blood sugar levels which otherwise rose in the control group." In addition to that, markers of oxidative stress declined in the yoga group by 20%, on average.
Yoga may curb oxidative stress
The significance of that is not clear. Dr Hegde said that if such a decline in oxidative stress were sustained over time, it might lower the chances of diabetes complications. Further, long-term studies are needed to see whether that is the case, the researchers say.
According to Dr Hegde, yoga may curb oxidative stress because it stimulates the parasympathetic nervous system.
There are caveats. The yoga used in this study was a gentle form, Dr Hegde said, and parts of the practise were adapted for people who had additional health problems; certain poses were avoided in people who had heart disease, for example.
In the real world, yoga classes vary widely. Some are vigorous work-outs involving complicated poses that would not be appropriate for older adults with chronic health conditions.
Older adults with diabetes can look for yoga classes designed specifically for older people and those with chronic medical conditions. In the US, hospitals and local community centres are increasingly offering such classes.
(Reuters Health, Amy Norton, September 2011)