The lungs are stretched and expanded by the respiratory muscles and the postures. Many postures work specifically to open the chest, allowing a more efficient breathing cycle. Improved respiration means improved oxygenation of the blood, which in turn improves cellular metabolic rates and efficiency to every organ of the body. All the bending, twisting and stretching movements also have a beneficial effect on the internal organs. Digestion is improved by yoga, not just by the actual movements and stimulating pressures applied but also by improved respiration and circulation.
Some postures exert direct pressure on the kidneys helping to eliminate waste products.
As yoga teaches our bodies to relax and be strong, it also teaches the mind. A relaxed and strong mind is one that functions efficiently, is able to concentrate, has good memory and recall and suffers little anxiety or fearfulness. As the mind relaxes in yoga, emotional over-reactions and compulsive attachment is decreased. Often people will use an attachment as a distraction from feelings of anxiety and tension. As the mind becomes calmer it is not necessary to grasp and hold onto people or situations as a way to fulfill our own needs.