The stresses of the 21st century are to blame, MacInerney explained, speaking in a calm, unhurried voice. A frenetic lifestyle leads many people to breathe by expanding their chests, but he teaches students to breathe instead with their diaphragms. Excessive chest breathing is unhealthy because it activates a flight response, which increases blood pressure and heart rate. Breathing with the diaphragm not only avoids this flight response, but also speeds digestion by pushing on the intestines and increasing blood supply to the liver and kidneys. Students use this breathing technique throughout a yoga class.
Classes are available for everyone from gymnasts to arthritic patients.
Instructors often begin sessions by asking students to release tension in their necks and shoulders. Next, they contort their bodies into poses, such as lying on the stomach and lifting the hands and chest off the ground. Finally, students finish with sitting exercises and positions that elevate the feet above the head. For nurses, good body posture is one of the most valuable lessons they can learn in yoga, MacInerney said. He teaches them to hold their shoulders back and chest up.