Respiratory and Cardiovascular Responses to Exercise

These flashcards cover the physiological responses of the respiratory and cardiovascular systems to exercise, including VO2max, blood pressure dynamics, and autonomic regulation.

Respiratory System Function

Responsible for gas exchange and metabolic rate; during exercise, tissue uses more $O_2$ and produces more $CO_2$.

VO2max Prediction

A method of predicting maximum oxygen consumption using Heart Rate (HR) at different workloads, based on the linear relationship between workload, HR, and $VO_2$.

Cardiac Output (CO)

The volume of blood pumped by a ventricle per minute ($CO = HR \times SV$).

CO Biological Factors

Cardiac output is typically higher in males, those with larger body size, larger muscle mass, and larger heart size; it lowers with aging.

Blood Flow Redistribution

During exercise, blood flow mostly goes to the working skeletal muscle and the skin (to help lose heat) while being reduced in the kidneys and GI tract.

Sympathetic Activity in Exercise

Causes vasoconstriction in the kidneys, GI tract, and non-exercising skeletal muscle to redirect blood flow.

TPR (Total Peripheral Resistance)

The overall resistance to blood flow which decreases during exercise because arterioles dilate in exercising muscle and skin, despite constriction in the kidneys and GI tract.

Blood Pressure Changes

During exercise, Systolic BP increases significantly, while Diastolic BP shows little change.

Mean Arterial Pressure (MAP) Formula

$\text{MAP} = \text{CO} \times \text{TPR}$; it increases slightly during exercise.

Heart Rate (HR) Regulation

Increases during exercise due to decreased parasympathetic (vagal) input and increased sympathetic input to the SA node.

Stroke Volume (SV) Regulation

Increases during exercise due to increased contractility triggered by sympathetic stimulation.

Vagal Braking

The parasympathetic inhibition of the heart rate; exercise shifts the autonomic balance to reduce this braking, allowing the SA node to fire faster.