Exercise Physiology Notes PDF

1 1. Hypertensive Response to Exercise (HRE): Definition: HRE is an excessive rise in systolic blood pressure (BP) during exercise, typically over 210 mmHg for men and 190 mmHg for women. Occurrence: This response can happen even in people without known cardiovascular issues and is often regarded as...

1 1. Hypertensive Response to Exercise (HRE): Definition: HRE is an excessive rise in systolic blood pressure (BP) during exercise, typically over 210 mmHg for men and 190 mmHg for women. Occurrence: This response can happen even in people without known cardiovascular issues and is often regarded as an abnormal physiological reaction. Long-Term Risks: Studies indicate that HRE could predict future hypertension and increase the risk of cardiovascular mortality. 2. Mechanisms Behind HRE: Impaired Vasodilation: Normally, during exercise, the blood vessels dilate due to the endothelial response to shear stress from increased blood flow. In HRE, endothelial function is compromised, limiting vasodilation, which contributes to the excessive BP increase. Nitric Oxide (NO) Deficiency: Patients with HRE often have reduced nitric oxide activity, which is critical for vasodilation, even in young individuals without cardiovascular risk factors. Arterial Stiffness in Older Adults: In elderly individuals, increased arterial stiffness decreases arterial compliance. This reduces the blood vessels’ ability to buffer changes in blood pressure, leading to higher BP during exercise. 3. Abnormal Cardiovascular Responses in Hypertensive Patients: Greater Pressure & Heart Rate Increases: People with hypertension experience a more pronounced rise in BP, heart rate, and sympathetic nervous system activity during exercise compared to normotensive individuals. Lower Maximal Oxygen Uptake: Sedentary hypertensive patients have a reduced maximal oxygen uptake (VO2max) during dynamic exercise, which reflects lower cardiovascular fitness compared to non-hypertensive individuals. Increased Risk of Cardiac Events: Hypertensive patients are at a higher risk for adverse events like angina, myocardial infarction, or stroke during exercise due to their abnormal cardiovascular responses. 4. Abnormal Heart Responses in Coronary Artery Disease (CAD): Physical Symptoms: Patients may experience cool, clammy skin, dizziness, cyanosis, nausea, and angina during exercise, which typically subsides during recovery. Abnormal Heart Rate (HR) and BP Responses: Increased HR: May indicate poor conditioning or dysrhythmia. Decreased HR: Could signal a conduction defect, ischemia, or left ventricular dysfunction. Excessive BP Increase: A rise above 225/90 mmHg may predict future hypertension. Exercise-Induced Hypotension: A drop in BP could be associated with valve disease, CAD, or left ventricular dysfunction. Pump Function and Cardiac Output: In CAD, the heart may struggle to maintain a normal cardiac output due to restricted blood flow, resulting in limited stroke volume and decreased VO2max. 5. Exercise-Induced Dyspnea (EID): Breathlessness: Shortness of breath during exercise is common in children, adolescents, and young adults, often due to reaching their physiological limits rather than underlying disease. Deconditioning: Individuals who are untrained, obese, or recently ill may experience lower exercise tolerance, reduced cardiac output, and breathlessness due to decreased oxygen uptake. 6. Abnormal Respiratory Response to Exercise: Enhanced Ventilatory Response: Elevated ventilation per carbon dioxide production ratio (Ve/VCO2 slope) is seen in conditions like heart failure and cardiomyopathy, where ventilation is excessive relative to metabolic needs. Ventilation/Perfusion (V/Q) Mismatch: Seen in congenital heart defects and acquired heart failure, this mismatch can reduce gas exchange efficiency, leading to an elevated Ve/VCO2 slope. 7. Exercise-Induced Bronchoconstriction (EIB): Bronchospasm: Asthmatic individuals may experience bronchoconstriction after 5- 8 minutes of intense exercise, causing a drop in forced expiratory volume (FEV1). Prevalence in Athletes: Elite athletes have a higher incidence of EIB, often due to airway dehydration from breathing in large volumes of air, which can be worsened by cold air. 8. Exercise-Induced Laryngeal Obstruction: Laryngeal Dysfunction: Common in young female athletes, this condition causes stridor (noisy breathing) during peak exercise, which usually ceases upon reducing exertion. Diagnosis: Can be confirmed through laryngoscopy during exercise in specialized centers. 9. Hypertrophic Cardiomyopathy (HCM): Differentiation from Athletic Training: While both trained athletes and HCM patients may have left ventricular wall thickening, trained individuals typically have a higher VO2max. Symptoms: Patients with HCM may show an early rise in HR to compensate for a reduced stroke volume due to impaired ventricular relaxation. 10. Thoracic Dysfunctional Breathing: Role of the Diaphragm: The diaphragm, critical for both respiration and trunk stability, may develop a dysfunctional pattern in conditions like COPD, leading to shallow, upper chest breathing, and making exercise more difficult. Hyperinflation Pattern: In such patients, an increase in expiratory reserve volume with a reduction in inspiratory reserve volume suggests dynamic hyperinflation, a pattern that further limits breathing efficiency during exercise.  2 1. Purpose of Exercise Testing Goal: Exercise testing measures the body's physiological responses to controlled increases in exercise intensity. Key parameters like heart rate, blood pressure, respiratory rate, and oxygen levels provide insights into the cardiovascular and respiratory conditioning and overall fitness level of the patient. Significance: By analyzing these responses, clinicians can assess the efficiency of the heart and lungs, determine physical fitness, and diagnose potential impairments in cardiopulmonary function. 2. Mechanisms of Exercise Limitation Factors Affecting Exercise Capacity: The document outlines several factors that can limit exercise capacity, which include: Pulmonary (Lung): Issues with ventilation, respiratory muscle strength, and gas exchange. Cardiovascular (Heart and Blood Vessels): Reduced stroke volume (amount of blood pumped per heartbeat) and irregular heart responses. Peripheral (Muscles and Nerves): Conditions like muscle atrophy, low oxidative capacity, and malnutrition that affect muscle performance. Psychological and Environmental Factors: Motivation, surroundings, and perceived exertion also play a role in limiting exercise performance. 3. Cardiopulmonary Exercise Test (CPET) Process: CPET typically involves the use of a treadmill or cycle ergometer, during which several physiological parameters are measured, such as oxygen consumption (VO2), carbon dioxide production (VCO2), and respiratory exchange ratio (RER). Purpose: CPET is crucial for assessing both submaximal and maximal exercise responses. It’s commonly used to evaluate unexplained exercise intolerance, functional capacity, and to provide data for exercise prescriptions and rehabilitation. 4. Clinical Indications for CPET Reasons to Conduct CPET: The test helps evaluate causes of dyspnea (shortness of breath), distinguish between cardiac, pulmonary, or peripheral limitations, and monitor rehabilitation progress. It’s also useful in pre-operative evaluations, risk assessment, and determining a safe exercise intensity for patients. Contraindications: Absolute Contraindications: Include acute myocardial infarction, unstable angina, severe arrhythmias, and conditions like severe aortic stenosis or uncontrolled heart failure. Relative Contraindications: Examples include significant arterial hypertension, certain valvular heart diseases, and physical impairments that might limit the test’s safety. 5. Safety Measures and Patient Preparation Patient Preparation: Patients are advised not to eat or smoke for 2-3 hours before the test and to avoid strenuous physical activity for at least 12 hours. They should also be informed about the procedure, risks, and potential complications. Early Termination: The test may be terminated if the patient requests it or if symptoms like chest pain, severe blood pressure changes, or dizziness occur. 6. Exercise Testing Equipment and Protocols Common Devices: The treadmill and cycle ergometer are the primary devices used for dynamic exercise testing. Protocols: Incremental (Graded) Exercise Test: The load increases at set intervals, often every 1-2 minutes. Ramp Test: The load gradually increases continuously, usually every 30 seconds. Constant Load Test: The patient exercises at a fixed workload, typically calculated as a percentage (50-70%) of their estimated maximum capacity. 7. Field Tests for Functional Capacity 12-Minute Walk Test: The patient is asked to walk as far as possible in 12 minutes. This test measures aerobic capacity and endurance. Harvard Step Test: Measures aerobic fitness by having the patient step up and down on a platform at a set rate. The heart rate is measured during recovery to assess fitness level. 8. Key Parameters Measured in CPET Electrocardiogram (ECG): Monitors the heart's electrical activity. Oxygen Consumption (VO2): Reflects the body's ability to use oxygen, calculated using the Fick equation. Ventilatory Parameters: Include minute ventilation (VE), breathing reserve (BR), and respiratory exchange ratio (RER), which provide insights into respiratory efficiency and potential limitations. VO2 Max: The maximum rate of oxygen uptake, which indicates cardiovascular fitness and endurance. VO2 max is the most accurate measure of aerobic capacity and is particularly important for evaluating cardiorespiratory health. 9. Indicators of Aerobic and Anaerobic Thresholds Anaerobic Threshold (AT): The point where oxygen supply is no longer adequate, and anaerobic metabolism begins, producing lactate and leading to metabolic acidosis. Determining AT: This is typically assessed by the V-slope method, analyzing the relationship between VO2 and VCO2 to determine when CO2 production exceeds oxygen consumption due to lactate accumulation. 10. Clinical Applications and Patient Scenarios Applications: CPET data can be used to guide exercise prescriptions, evaluate fitness, monitor disease progression, and assess treatment responses. Scenarios: CPET can highlight unique patterns based on different clinical conditions, such as a lower VO2 max in patients with heart or lung diseases, or high VO2 max in trained athletes.  3 Cardiac rehabilitation is a comprehensive program aimed at restoring a patient’s physical, psychological, and mental health to the best possible level after suffering from heart disease. This program seeks to improve healthy lifestyle behaviors to reduce or slow the progression of heart disease, helping patients "add life to years." The program is divided into three phases and is offered to patients who may benefit from it, particularly those with ischemic heart disease or those who have experienced heart attacks or undergone heart surgeries. Phases of Cardiac Rehabilitation Phase 1 (In-Hospital Phase): This phase begins immediately after the patient’s health stabilizes in the intensive care unit, often within 24-48 hours following the incident or surgery. The program includes light exercises performed under close supervision with heart monitoring devices. The primary goals in this phase are to mitigate the effects of prolonged bed rest, alleviate anxiety and depression, and assess the effects of medications on the patient. Phase 2 (Outpatient Rehabilitation): After discharge from the hospital, the patient enters an outpatient rehabilitation program, where they engage in monitored physical exercises. This phase focuses on improving heart health and educating patients on managing risk factors, such as proper nutrition and quitting smoking. Phase 3 (Long-Term Maintenance): In this phase, patients are guided to independently perform exercises and self-care activities with the aim of maintaining heart health and reducing the risk of future heart attacks. The Cardiac Rehabilitation Team The cardiac rehabilitation team consists of various healthcare specialists, such as cardiologists, nurses, physical therapists, nutritionists, and mental health professionals. Support from family and friends is also an essential part of the program to ensure emotional support and involvement in patient care. Contraindications for Starting Cardiac Rehabilitation Certain conditions may prevent the initiation of exercise in the cardiac rehabilitation program, including: Unstable angina. High blood pressure (above 200/100 mmHg). Valve problems, such as severe aortic stenosis. Unstable heart arrhythmias. Uncontrolled diabetes. Severe musculoskeletal issues preventing exercise. Exercises in Phase 1 In the hospital, patients are encouraged to perform simple exercises such as breathing exercises and walking, in addition to light joint movements, gradually increasing their physical capacity over time. Examples of Activities by Exercise Level (METS): Level 1 (1-1.5 METs): Simple movements such as ankle and wrist rotations or light leg lifts. Level 2 (2.5-3.5 METs): Seated activities, including some exercises with light weights. Level 3 (3.5-4.5 METs): Standing exercises such as side trunk bends and marching in place. Exercise Termination Criteria Exercises are stopped immediately if the patient experiences any of the following symptoms: Severe fatigue. Abnormal changes in blood pressure. Heart arrhythmias, such as irregular heartbeat. Severe shortness of breath, nausea, or dizziness.  4 Phase 2 Cardiac Rehabilitation (Convalescent Stage) This stage of cardiac rehab is an outpatient program focusing on gradual, supervised exercise. It involves personalized exercise routines, often with ECG monitoring, to safely support cardiac recovery. Conducted at hospitals or outpatient clinics, this phase usually spans 3 to 6 months. Generally, the goal is for patients to achieve 9 METS (a metabolic equivalent level), with 5 METS considered the minimum level required for basic daily activities (ADLs). Objectives 1. Improve Cardiovascular Health: Enhance heart function, endurance, flexibility, and physical capacity. 2. Monitor ECG: Detect any arrhythmias or irregular heart responses during exercise. 3. Boost Psychological Health: Help patients regain confidence and reduce anxiety. 4. Prepare for Work Return: Gradually increase exercise load to safely prepare the patient for work. 5. Promote Healthy Lifestyle: Work with family and close relatives to support lasting health habits. 6. Educate on Safe Exercise: Guide patients on correct exercise techniques and safety. Eligibility This phase is typically recommended for: 1. Patients with a history of myocardial infarction. 2. Those who have undergone coronary bypass or angioplasty. 3. Patients with valvular or congenital heart surgery. 4. Individuals with stable angina. Exercise Monitoring 1) Heart Rate (HR): Used as an index of myocardial work and oxygen consumption. A linear increase in HR aligns with increased exercise intensity. Certain medications, such as beta blockers, may affect HR response. HR is measured before, during, and after exercise, reflecting the body's recovery. 2) Blood Pressure (BP): An indicator of myocardial oxygen needs, with a linear increase in systolic BP during exercise. Abnormal BP responses include excessive rise, failure of systolic BP to increase, or a sudden drop, which could indicate shock. 3) ECG Monitoring: Used to identify potential arrhythmias (e.g., premature ventricular contractions, ventricular tachycardia, or fibrillation). S-T segment changes can indicate coronary artery disease severity or exertion response. 4) Signs of Exertional Intolerance: Symptoms like extreme fatigue, persistent dyspnea, dizziness, chest pain, pallor, or excessive sweating indicate exercise should be stopped and evaluated. 5) Rating of Perceived Exertion (RPE): A subjective scale (Borg Scale) for gauging the patient's perceived effort during exercise. RPE helps patients, especially those on HR-modifying medications, to monitor their exertion level. Exercise Prescription and Program Structure 1. Program Mode: Single mode: Continuous activities like walking. Circuit training: Alternates between exercises, e.g., cycling for lower limbs, rowing for upper limbs. 2. Training Style: Continuous Training: Non-stop activity. Interval Training: Exercise intervals followed by rest. 3. Duration: 15-60 minutes based on tolerance, with warm-up and cool-down phases. 4. Progression: Initially, low-intensity, longer-duration sessions, progressing gradually in intensity. Exercise Frequency and Intensity Depends on functional capacity in METs: > 5 METs: 3-5 sessions/week. 3-5 METs: 1-2 sessions/day.