The benefits of yoga practice continue to expand. The expansion is literal in a recent study from Khon Kaen University in Thailand. Young and healthy Thais who participated in just 18 short yoga sessions showed significant improvements on six of seven measures of respiratory function.
Fifty eight volunteers, all around 20 years old, participated in the six-week study. The researchers chose five hatha yoga positions designed to improve chest wall function, including the cat, tree and camel positions. Half of the volunteers did hatha yoga during 20-minute sessions, three times a week. The control group did not do the exercises, but continued their usual lifestyles, and did not smoke or drink.
The researchers obtained baseline lung expansion and lung volume measures on the volunteers before the experiment and took final measurements after the experiment ended. They used a tape measure to determine lung expansion capacity, measuring the upper chest (sternum), middle chest (rib 5) and lower chest (rib 8). “Chest wall expansion allows individuals to get more air to the base of the lung,” explained lead researcher Raoyrin Chanavirut, in a press release. “Greater expansion of the chest wall provides more oxygen with each breath and requires less effort to breathe.”
The researchers also used a spirometer to measure tidal volume, forced expiratory volume (both FEV1 and FEV25-75%) and forced vital capacity (FVC). The volunteers who did yoga over the six-week period significantly improved their chest wall expansion at all three measurement points, and also showed significantly better FEV1, FEV25-75% and FVC. The yoga sessions did not affect tidal volume, that is, the amount of air that passes in and out of the lungs in an ordinary breath.
“This research suggests that short-term yoga exercise improves respiratory breathing capacity by increasing chest wall expansion and forced expiratory lung volumes,” said Chanavirut. “These findings may benefit people suffering from illnesses that affect breathing, including asthma.”