Cardiovascular Responses to Exercise

What is cardiac output?

The amount of blood ejected from the left side of the heart to the body in L/min.

What determines cardiac output?

It is determined by heart rate and stroke volume.

How is heart rate defined?

The speed at which the heart beats, measured in beats per minute (bpm).

What is stroke volume?

The amount of blood ejected with each contraction of the heart, measured in ml/beat.

How is cardiac output calculated?

Cardiac output = heart rate x stroke volume

What happens to cardiac output during acute exercise?

Both heart rate and stroke volume increase until their maximum levels are achieved.

What does prolonged exercise lead to in terms of stroke volume?

Stroke volume decreases while heart rate increases to maintain cardiac output.

What is cardiovascular drift?

A gradual increase in heart rate and a decrease in stroke volume during prolonged exercise.

Cardiovascular drift

1. Body participates in prolonged exercise

2. Body temp increases increases due to production of heat from respiration

3. Sweating decreasing blood volume

4. Reduced blood plasma increases viscosity

5. Stroke volume decreases

6. Heart rate increases to maintain cardiac output

What is VO2?

The volume of oxygen consumed by the body, assessed by measuring gas concentration and air volume during exercise.

What happens to VO2 max as exercise intensity increases?

VO2 max increases until the individual reaches their physical limit.

How is VO2 max defined?

Maximal rate at which an individual can take in and use oxygen.

What contributes to VO2 max?

Maximum cardiac output and maximum arteriovenous oxygen difference.

What is maximum cardiac output?

The highest volume of blood the heart can pump per minute.

What does maximum arteriovenous oxygen difference represent?

The amount of oxygen extracted by the muscle from the blood.

What does Fick's law explain regarding VO2 max?

It states that both maximum cardiac output and maximum a-VO2 difference must be optimised for higher VO2 max.

Factors that affect cardiac output

Age, sex, level of fitness, type/intensity of activity

How does age affect VO2 max?

VO2 max increases until a peak is reached around age 20 for males and mid to late teens for females, then declines with age.

What is the rate of decline in VO2 max determined by?

an active healthy lifestyle

Why do females typically have a lower relative VO2 max than males?

Females have a higher percentage of body fat, lower haemoglobin concentration, smaller heart and lungs

How does fitness level influence VO2 max?

Trained individuals typically have a higher VO2 max than untrained individuals due to physiological adaptations.

What do trained individuals have that untrained individuals don’t?

increased stroke volume and oxygen carrying capacity

What is the impact of dynamic exercise on blood pressure?

Systolic blood pressure increases, while diastolic blood pressure remains constant.

What is the impact of static exercise on blood pressure?

Both systolic and diastolic blood pressure increase.

What type of activities can lead to a higher recorded VO2 max?

Activities that use larger muscle mass and recruit greater numbers of motor units.