Exercise Physiology | Zoology Optional Notes for UPSC PDF Download

Introduction

Exercise Physiology explores the body's response to physical activity, delving into the intricate mechanisms that maintain homeostasis during exercise. At rest, the parasympathetic tone governs various physiological functions. However, exercise triggers the sympathetic nervous system, prompting a comprehensive response to meet increased demands in physical, metabolic, respiratory, and cardiovascular aspects.

Function

Exercise yields numerous health benefits, affecting cognition, flexibility, cardiovascular health, glycemic control, mood, cancer risk, and bone density. Properly executed exercise programs induce acute and chronic adaptations, enhancing the body's efficiency in performing diverse activities.

Acute Adaptations to Exercise

Cardiovascular Responses

• Cardiovascular adjustments ensure optimal oxygen and carbon dioxide transport, maintaining pH balance in active tissues.
• Cardiac Output (Q): The heart's pumping capacity increases linearly with working rate to meet heightened oxygen demand.

Blood Pressure

• Systolic blood pressure increases linearly, while diastolic pressure remains near rest levels.
• Post-exercise hypotension may occur, with blood pressure dropping below pre-exercise values.

Coronary Circulation

• Coronary arteries supply blood and nutrients to the myocardium, adapting to increased demands during exercise.

Pulmonary System Adaptations

• Pulmonary ventilation, coordinated with the cardiovascular system, responds to increased cardiac output.
• Lung blood flow increases, enhancing gas exchange surface area.

Musculoskeletal System

• Three muscle fiber types (Type-I, Type-IIa, Type-IIb) exhibit distinct characteristics and adaptations.
• Exercise-induced stress activates satellite cells, promoting muscle repair and growth.

Resistance Exercise

• Resistance training increases peripheral vascular resistance, impacting small arteries and vascular resistance.

Endurance Training

• Endurance training influences muscle fiber types, mitochondrial density, and metabolic properties.

Hormonal Responses to Exercise

• Endocrine responses include elevated cortisol, epinephrine, norepinephrine, dopamine, and growth hormone levels.
• Immunological adjustments demonstrate improved immune function with moderate training.

Chronic Adaptations of Exercise

Skeletal Muscle Adaptations

• Endurance training enhances slow-twitch fiber cross-sectional area and recruitment pathway effectiveness.
• Resistance training leads to greater force development in trained muscles.

Ligament and Tendon Adaptations

• Prolonged training increases ligament and tendon cross-sectional area, strengthening insertion sites.

Metabolic Adaptations of Prolonged Exercise

• Cardiac adaptations result in increased cardiac output and higher VO2max post-exercise.
• Long-term endurance training influences heart rate, stroke volume, and plasma volume.

Long Term Respiratory Adaptations

• Upper lung blood flow increases, and respiration rate rises after prolonged endurance training.

Absolute Contraindications to Exercise

Various health conditions, such as unstable cardiovascular disease, uncontrolled asthma, COPD, cancer, blood disorders, diabetes, osteoporosis, and unexplained dizzy spells, warrant caution or restrictions in exercise.

Adverse Effects

Musculoskeletal Adverse Effects

• Sudden force development or repetitive movements may lead to musculoskeletal strain, tear, or fracture.

Cardiovascular Events

• Epidemiological studies highlight the prevalence of sudden cardiac arrest, particularly in men.