Comprehensive review on the benefits and physiological basis of yoga

Table 1 Benefits of yoga

Systems	Mechanism	Benefits
Psychiatric	Enhances gamma-aminobutyric acid, oxytocin, serotonin and melatonin levels	Useful in stress, anxiety, insomnia, depression, obsessive compulsive disorder, posttraumatic stress disorder, and schizophrenia
Neurological	Increased grey matter volume, improved neural network flexibility, and modulation of ascending reticular activating system	Improvement in cognitive functions such as memory, attention, executive function and psychomotor speed
Metabolic	Reduction of blood sugar, cholesterol, hypertension, and oxidative stress	Reduction of blood pressure, heart rate, and body mass index and improvement of glucose tolerance
Cardiovascular	Down-regulation of the hypothalamopituitary adrenal axis, the sympathetic nervous system and the renin-angiotensin-aldosterone system. Reduction in oxidative stress	Increased RR interval, heart rate variability, improved peak oxygen consumption, and exercise capacity. Reduction in atherosclerosis
Respiratory	Improvement in FEV1, FVC, FEV1/FVC, and peak expiratory flow rate	Better disease control in asthma patients, and better 6-minute walking distance of chronic obstructive pulmonary disease patients
Musculoskeletal	Activation of the muscle spindles by stretch, activation of Golgi tendon organs by contraction, improved flexibility, and increased relaxation	A complimentary treatment for myositis, fibromyalgia, idiopathic inflammatory myopathy, chronic low back pain, and knee osteoartrhritis
Inflammatory	Reduction ininterleukin-6, tumour necrosis factor-alpha, and C-reactive protein	Reduction of inflammation in chronic conditions such as heart disease, cancer, and rheumatoid arthritis
Oncological	Decrease in anxiety, better sleep quality, and reduction of inflammation	Improvement of sleep, reduction of fatigue, reduction of cognitive impairment, decrease of psychological distress, and amelioration of musculoskeletal symptoms in cancer survivors

FEV: Forced expiratory volume; FVC: Forced vital capacity.

Table 2 Guidelines to prevent adverse events during yoga

Guidelines
Standardisation of practices with essential steps: Posture (asana), breathing exercise (pranayama), and meditation (dhyana)
Avoidance of vigorous exercises, headstand (sirshasana), and hyperventilation
Practices under supervision
Training of instructors
Frequent health check-ups during practices