L22 Circulatory responses to Exercise

Question 1

Define static and dynamic exercise

Answer 1

static = muscle contracts and force is generated but no shortening occurs

dynamic = muscle contracts + shortens and joint angle changes

Question 2

graph the relationship between systolic, mean and diastolic blood pressure responses to incremental dynamic exercise. Provide an explanation for the apparent differences in these pressure responses

Answer 2

look up graph in the purple book

Systolic - due to ventricles always containing a functional residual blood volume due to inotropic effect on the heart

Diastolic - has slower filling

Question 3

Graph the relationship between total peripheral resistance and dynamic exercise intensity

Answer 3

negative curvilinear relationship. graph in the purple book

Question 4

Describe the mechanisms that account for the increase in stroke volume

Answer 4

1. enhanced cardiac filling in diastole + stronger systolic contraction
2. Normal ventricular filling but stronger systole contraction
3. Training adaptations that expand blood volume and reduce resistance to blood flow in peripheral

Question 5

Explain the phenomenon of cardiac drift and speculate as to the underlying mechanisms

Answer 5

= the progressive increase in HR and the decrease in stroke volume so that cardiac output remains the same
could be caused by dehydration or thermoregulation

Question 6

Explain how exercise intensity may influence the temporal pattern of the heart rate and systolic/mean/diastolic blood pressure response to static exercise

Answer 6

Progressive increase in BP with static exercise intensity and duration.

Both SBP and DBP increase - therefore mean obviously increases as well

Question 7

Describe now muscle sympathetic nerve activity changes during static exercise and effort of this on the periphery

Answer 7

it increases which causes progressive vasoconstriction in inactive muscle. Afterload is increased

Question 8

How high may blood pressure go in weightlifting and explain the role in intrathoracic pressure adds to a pressor response to increase blood pressure

Answer 8

It can rise to 480/350 mmHg. high intrathoracic. pressure adds to a pressor response to increase blood pressure.

Question 9

Explain how the Vo2, heart rate and blood pressure responses differ between arm and leg exercise and provide some reasons for this

Answer 9

@ max exercise, arms have lower max HR, O2 uptake and ventilation. Due to arms having smaller muscle mass + less motor units than legs

Question 10

Explain why snow shovelling may increase cardiac risk

Answer 10

There is a major blood pressure increase during snow shovelling. High afterload increases myocardial work