Challenges to the Cardiovascular System II

Flashcards covering cardiovascular responses to exercise, cardiac remodeling, pathophysiology, and aerobic fitness based on lecture materials.

Resistance Exercise (CVS Impact)

A form of exercise that alone does not improve the functional capacity of the Cardiovascular System (CVS).

Athlete Findings

Data showing that world-class shot putters (resistance) have higher LV wall thickness ($13.8\,mm$) compared to world-class runners ($10.8\,mm$), but runners have significantly higher LV volume ($154\,ml$ vs $122\,ml$).

Detraining

The time course of loss of adaptations after stopping prolonged intense endurance training; results in an increase in HR and a decrease in CO, SV, $O_2$ extraction, and $VO_2 max$ over 84 days.

Cardiac Atrophy in Spaceflight

A reduction in cardiac size and function observed after bed rest and spaceflight, characterized by decreased SV (from $131 \pm 2\,ml$ to $93 \pm 2\,ml$) and decreased CO.

Functional Hypertrophy

A normal adaptation of the heart to chronic pressure/volume overload that results in improved cardiac function.

Pathological Hypertrophy

A maladaptation of the heart to decreased cardiac work or increased afterload (e.g., from hypertension) that initially compensates for reduced function but eventually leads to cardiac failure.

Pathophysiological Challenges: Reduced Venous Return

Challenges including Sepsis, Anaphylaxis, General Anaesthesia, and Arrhythmia that disrupt cardiac filling.

Pathophysiological Challenges: Reduced Blood Volume

Challenges including Haemorrhage, Burns, Diarrhoea/Vomiting, and Dehydration that reduce preload.

Consequences of Inadequate Cardiac Output

Specifically results in inadequate $O_2$ distribution, $CO_2$ removal, hypotension, and circulatory collapse.

Local Signals for Upregulating CO

Direct effects from factors such as temperature, pH, $O_2$, $CO_2$, adenosine, NO, $Mg^{2+}$, and $K^{+}$ during exercise.

$$VO_2 max$$

The maximum ability of the body to utilise oxygen during exercise and an indicator of maximum aerobic capacity (ATP synthesis).

Determinants of $VO_2 max$

Factors including gender, size/stature, heredity, muscle fibre type, haematocrit, and training status.

$CO_{max}$ and $VO_2 max$ Relationship

The close direct relationship where maximal oxygen consumption (L/min) increases as maximal cardiac output (L/min) increases.