Breathing techniques (or pranayama) used in yoga increase the lungs capacity by strengthening all of the muscles involved in breathing. This is particularly important for people who tend to get bronchial conditions such as asthma. Better lung function has the added benefit of increasing the supply of fresh oxygenated blood to all of your cells, flushing out and supplying fresh nutrients to every cell in your body.
Circulation is also improved with our Asana (physical) practice, which not only increases the blood flow around the body it also helps to stretch the major blood vessels, improving their elasticity. Improved circulation means that your brain will receive more oxygen, improving alertness, memory, and mood. Vital organs receive a steady supply of the nutrients they need for optimal functioning.
Every system, every organ, every cell is guided in its functioning by hormones. The proper growth and functioning of the various parts of the body is possible when there is a balanced secretion of all these hormones. Any imbalance results in disease. Asanas balance the hormonal secretions from the various glands. The twisting and bending positions of the asanas, held for periods of time, place pressure on the various glands of the body, stimulating them and regulating their secretions.
Yoga is one of the only forms of exercise that triggers the para-sympathetic nervous system, which is responsible for the relaxation (or rest, digest and renew) response in the body lowering stress, a major cause of compromised immunity. This helps to balance our nervous system, improves our sleep our ability to respond to stress and our digestion.
Up to 80% of our immune system is located in the digestive tract, so having a healthy gut is crucial to a good immune system. Many yoga poses stimulate the digestive system, promoting better digestion. However, diet and exercise are not the only factors to contribute to a healthy digestive system. Stress can be a major cause of digestive issues. Which is why activating the para-sympathetic nervous system is extremely important for digestive health.