Physiology Week 3: Lecture 3

Cardiovascular Adaptations

Focuses on adaptations resulting from chronic exposure to exercise or physical activity.
Importance of understanding training principles: specificity, overload, individualization, rest recovery, progression, maintenance, detraining/reversibility.

Modality Specific Adaptations: Improvements in performance are greatest in the training modality used.
- Example: A runner sees more cardiovascular fitness improvements from running than cycling or swimming.
Cardiovascular Specific Adaptations: Include both central (heart-related) and peripheral (muscle and vasculature-related) adaptations.

Increase in frequency, intensity, or duration linked to improved VO2 max.
- Example: Training frequency increase from 2 to 4 days leads to VO2 max improvement.
Not all components equally influence change: intensity and frequency are most effective, duration has lesser impact.

People with lower initial fitness levels (e.g., VO2 max of 30-40 ml/kg/min) show greater improvement potential compared to those already fit (e.g., 50-60 ml/kg/min).
Factors influencing this include training age and genetic potential.

Key for maximizing cardiovascular adaptations; involves periodization and understanding super-compensation peaks.
Training at optimal times ensures maximum benefit.

Small reductions in training frequency, duration, or intensity result in minor decreases in VO2 max.
Highlights the "use it or lose it" principle in maintaining fitness levels.

Significant decreases in fitness markers post-detraining (e.g., VO2 max dropping from 62 to below 50 after 84 days).
Cardiac output and stroke volume also decrease; however, changes in heart rate are subtle without significant reflection of overall adaptations.

Focus on adaptations specific to the heart, including increased stroke volume and cardiac output.
- Cardiac Dimensions: Increased left ventricular mass and end-diastolic volume contribute to enhanced oxygen delivery.
- Concern: Hypertrophic Cardiomyopathy can negatively affect cardiac function; occurs in genetically predisposed individuals (e.g., certain populations including tall, muscular athletes).
- At rest and during submaximal exercise, cardiac output remains unchanged; at maximal exercise, it increases due to greater stroke volume and decreased heart rate.

Involve changes in the blood vessels and muscles, enhancing oxygen extraction.
- Vascular Structure and Function: Improvements in arterial size and endothelial function due to increased nitric oxide production, enhancing vasodilation.
- Clot Formation and Breakdown Capacity: Enhanced vasodilation efficiency reduces clotting tendencies and improves fibrinolysis, lowering cardiovascular disease risk.

Increased plasma volume enhances overall blood volume—decreased viscosity improves blood flow.
At rest, trained individuals typically show lower blood pressure. During exercise, blood pressure remains stable despite improved vasodilation due to increased cardiac output.

Most improvements in VO2 max occur within the first two months of training.
- Improvements derive from central (increased cardiac output leading to improved stroke volume) and peripheral adaptations.
- The A-VO2 difference remains relatively unchanged; the efficiency of oxygen delivery is primarily impacted by cardiac output, especially stroke volume at maximal effort.

Define central cardiovascular adaptations.
Explain hypertrophic cardiomyopathy and associated population risks.
Discuss cardiovascular adaptations related to Cardiac Output in aerobic exercise.
Define peripheral cardiovascular adaptations and their significance.