Pranayama.
‘Prana’ means breath, respiration, life, vitality, energy or strength.
‘ayama’ means stretch, extension, expansion, length, breadth, regulation, prolongation, restraint or control.
Pranayama therefore means the prolongation of breath and its restraint. To learn pranayama is to learn techniques to make the respiratory organs move and expand intentionally, rhythmically and intensively. During normal inhalation, an average person takes in about 500 cubic centimetres of air; during deep inhalation the intake of air is about six times as great, amounting to almost 3000 cubic centimetres. During prolonged holding of breath, a slowing of the heart rate is observed. Learning these rhythmic breathing techniques brings steadiness, calmness and aids deep, peaceful relaxation.

Stress.
Different people respond to the same stressful situation with different levels of intensity. Some may become irritable or angry, others confused or depressed. Regardless of how stress manifests and how one deals with it, stress has been proven to increase likelihood of heart disease, stroke, type 2 diabetes, depression, IBS/gut issues, immune/pain disorders and premature aging.
To effectively reduce stress, the mind and body cannot be treated as separate components. Tension associated with stress is stored in muscles and the nervous system. Yoga relaxation methods have a profound effect on the central nervous system, as well as the circulatory, respiratory & digestive systems. When a part of the body is tense, circulation to that area is decreased, reducing immunity. Yoga (the physical poses and breathwork combined) helps to improve circulation, improved blood flow helps stabilise heart rate and blood pressure, deeper, slower breathing allows a higher intake of oxygen.