Cardiovascular Response to Activity

Question 1

HR Response

Answer 1

Linear increase with work rate and O2 uptake

Magnitude of increase depends on multiple factors

Question 2

HR max=

Answer 2

220 - age (+/- 10 bpm)

Question 3

SV

Answer 3

Stroke Volume

Question 4

SV =

Answer 4

End diastolic volume - End systolic volume

Question 5

Maximum SV =

Answer 5

100-120 ml per beat

Question 6

SV response

Answer 6

Enhanced diastolic filling
More forceful systolic contraction
Peripheral adaptations reduce resistance to blood flow

Question 7

Frank-Starling Law

Answer 7

The force of contraction of the cardiac muscle remains proportional to its initial resting length

Question 8

Enhanced systolic emptying

Answer 8

Occurs because the ventricles always have residual volume; catecholamine release enhances myocardial contractile force to augment stroke power

Question 9

During exercise in healthy adults, SV increases _____ with work rate until it reaches near maximum at ~____ of aerobic capacity

Answer 9

curvilinearly; 50%

Question 10

At higher intensities, SV may actually ____

Answer 10

Decrease

Question 11

Cardiac Ouput

Answer 11

(Q)
The amount of blood pumped by the heart during a 1-minute period
Reflects functional capacity of the cardiovascular system

Question 12

Cardiac Output at rest

Answer 12

Varies considerably at rest
5L average for males
4L average for females

Question 13

Cardiac Output distribution at rest

Answer 13

1/5 to muscle tissue

4/5 to digestion, liver, spleen, brain, and kidneys

Question 14

Cardiac Output during exercise

Answer 14

Increases linearly with increases in work rate

HR increases above 50% VO2 max, combination of HR and SV below

Question 15

Hormonal vascular regulation of blood flow

Answer 15

Decreased PO2 and increased norepinephrine and endothelial shear stress, NO is released causing vasodilation

Question 16

During exercise, blood flow increases to…

Answer 16

Muscles; Heart; Brain; skin

Question 17

Maximal Cardiac Output and VO2 Max

Answer 17

Low maximal oxygen consumption corresponds with low maximal cardiac output
5-6L increase in blood flow accompanies each 1-L increase in oxygen consumption above resting value

Question 18

Blood Pressure acute response

Answer 18

Linear increase in systolic BP
Max systolic is 190-220 during exercise, shouldnt exceed 250
Diastolic should not change much but shouldnt exceed 115

Question 19

a-v O2 difference during exercise

Answer 19

Blood O2 in arterioles doesnt change much, but gets reduced in veins

Question 20

Factors affecting a-v O2 difference

Answer 20

Cardiac output diverted to active tissue

Some tissues temporarily reduce blood supply

Training redirects a greater portion of circulation to muscle

Question 21

Factors affecting a-v O2 difference 2

Answer 21

Increase in skeletal muscle microcirculation

Increased capillary to fiber ratio

Increase in size and number of mitochondria

Augmenting aerobic enzyme activity

Improvement of muscle ability to produce ATP

Question 22

Cardiovascular Drift

Answer 22

Downward drift in cardiovascular response during prolonged steady rate exercise
Lower stroke volume from lower plasma volume leads to increased HR to maintain cardiac output

Question 23

Resistance Exercise

Answer 23

HR and BP increase

SV increases significantly during eccentric phase

Question 24

Isometric Contractions

Answer 24

Increases in BP and HR at 20%

Above 20% contraction, sharp increase in SBP

Question 25

Factors that produce additional oxygen cost at higher intensities of arm exercises

Answer 25

Lower mechanical efficiency

Recruitment of additional stabilizing musculature

Question 26

Changes in cardiovascular function results from

Answer 26

Increased plasma volume
Decreased HR
Increased SV
Increased Maximum CO
Increased O2 extraction
Increased Blood flow
Decreased BP