Physiological effects of yogic practices

Dr. Madanmohan Professor and Head, Department of Physiology

&Director, CYTER

Learning objectives

1. State why yoga should be introduced in medical curriculam as a branch of physiology and contemporary medicine.

2. Briefly describe the effects of yoga training on physiological functions.

3. Briefly explain the beneficial effects of pranayam.

4. Briefly explain the mechanism of action of yoga.

5. In a tabular form, give the differences between yoga and physical exercise.

Yoga as a branch of physiology and contemporary medicine

Why?

Relevance of yoga to medicos

1. Increased awareness and interest in health and natural remedies

2. Yoga is holistic health science3. Best lifestyle ever designed

4. Time–tested and effective5. Physician practicing yoga: better guide, stress free, calm, more stamina 6. Better student/doctor

Physiological effects of yoga practices

• Immediate: acute effect.

• Long – term: training effect improves physiological functions.

• Response varies with:• Duration• Intensity • Type of practices

Physiological effects of yoga training1.Metabolism2.Musculo-skeletel3.Neurophysiological4.Autonomic balance5.Cardiovascular6.Respiratory7.Better immunity8.Ability to withstand stressors

Metabolism

• resting O2 consumption and metabolic rate.

• Yogis in underground pits and water-tight chambers.

Biochemical changes:• Improved lipid profile• Decrease in blood glucose,

catecholamines

Hematological changes:Increase in hemoglobin, better immunity

Musculo-skeletal

Isometeric/static/sustained contraction:

• Biochemical changes

• Stimulate muscle growth

• Increase in strength and endurance

• Better performance, lesser fatigue

Slow bending, sustained stretch improves:

• Musculo-skeletal flexibility

• Range of joint movements

• Posture improves

• ? Reflexogenic effects

Slow movement + breathing + awareness

Improves concentration power → meditation

Mind–body-breath coordination → psychosomatic health, concentration power

Neurophysiological

Faster:Auditory reaction time ( ART )Visual reaction time ( VRT )Improved speed and dexterity

Meditation: Predominant alpha waves: mind is relaxed. Decreased anxiety and stress levels. Less increase in anxiety score in stressful situations (exam).Re-orients functional hierarchy of CNS

Autonomic control

Nadi shuddhi: stimulates parasympatheticKapalabhati: stimulates sympathetic

Breathing through:Left nostril: decreases sympathetic activityRight nostril: increases sympathetic activity

Capable of controlling autonomic function

Overall effect: restores autonomic balance

Cardiovascular

• Decrease in resting HR & BP: less load on heart, more reserve

• Head below the heart postures: improve baroreflex regulation

• Exercise-incluced stress is less severe: better efficiency and exercise tolerance

Improves cardio-respiratory function.

Respiratory

Respiration is unique:• Automatic• Can be greatly modified voluntarily• Respiration ↔ visceral functions

Pranayam

Rapid, deep, bellows type (bhastrika): Speeds circulation

Increases blood pressure and heart rate

Slow, deep, rhythmic breathing (nadi shuddhi): Calms mind Decreases BP and HR

Increases strength of respiratory muscles Efficient ventilation

Slow, deep yogic breathing is economical

Normal Shallow DeepVolume 500 200 1000

Rate 12 30 6

Ventilation 6000 6000 6000

Dead space 150 150 150

Dead space 1800 4500 900 ventilation

Alveolar 4200 1500 5100 ventilation

Benefits of pranayam

Increase in:1. Vital capacity (VC)2. Maximum inspiratory pressure (MIP)3. Maximum expiratory pressure (MEP)4. Breath holding time (BHT)

Decrease in: Resting respiratory rate and oxygen consumption

Benefits of pranayam

1. Economical, better O2 supply, ↓BP

2. Calms nervous system and mind3. Facilitates meditation4. Enhances vitality, health and healing5. Massages abdominal viscera6. Increases venous return7. Improves respiratory muscle strength8. Improves lung compliance and capacity

Overall benefits of yoga

1. Improved physiological and physical fitness2. Mind is calm, tranquil and one–pointed3. Improved mood, sleep, sense of well-being4. Improved memory, intellect and problem

solving ability

5. Flowering of creative abilities

Changes are consistent and measurable

Mechanism of action

• Strengthens, sooths, relaxes body and mind → promotes healing

• Decreases muscle tension → conserves energy• Improves immunity: relaxation is opposite to stress• Modulates hypothalamo–hypophysial–adrenal axis• Restores autonomic balance Psycho-neuro-immuno-endocrinological: health, stress, illness

Physical exercise:• -------

• Competitive

• Awareness: outer

• Muscle activity not harmonious

• Rapid forceful movements

Yoga:• Holistic

• Non-competitive

• Inner awareness

• Harmonious

• Slow dynamic or steady stretched

Contd…..

• High impact• High muscle tension

and energy consumption

• Risk of injury high• Breathing taxed• Sympathetic

dominant

• Low impact• Low

• Low• Controlled• Parasympathetic

dominant

….Contd