Chpt 9: Cardiorespiratory Response to Acute Exercise

1. What is the cause for an increase in HR just prior to exercise?

·        Parasympathetic withdrawal

·        Sympathetic stimulation, body is getting ready for exercise

·        Anticipatory response

o   Vagal tone decreases (parasympathetic stimulation)

o   Norepinephrine and epinephrine increase (sympathetic stimulation)

2. How is max HR estimated?

220-age

3. What does it mean when it is said that max HR is “highly reproducible?”

·        They same max heart rate can be achieved multiple times

4. What is steady-state HR?

HR plateaus constant wrkld

7. What are the three factors that increase stroke volume as an individual goes from rest to exercise?

·        Preload – frank-starling mechanism, as stretch increases (preload, EDV), contractile strength increases increasing SV

·        Contractility – increase in NE and EPI

·        Decrease in afterload – resistance to ejection of blood

8. Be able to explain the Frank-Starling Mechanism.

·        Increase in EDV, heart stretches and snaps back with stronger contraction = increase SV

9. What is preload?

·        Amount of blood in heart before contraction

·        EDV

10. What is afterload?

arterial resistance to blood being ejected

11. Be able to explain why preload increases with exercise, and why this results in increased Q.

·        Preload = EDV, after diastole

·        Start to exercise = increase venous return via skeletal muscle pump

·        Stretches heart and results in stronger contraction

·        Movement increases venous return increasing EDV increasing SV and Q bc frank-starling

13. What is responsible for the increase in Q above 50% VO₂max?

HR

14. What is the Fick equation?

·        VO2 = Q * (a-v)O2 difference

     = (HR*SV) * a-vO2 difference

15. What aspect of the Fick equation refers to delivery?

Q

16. What aspect of the Fick equation refers to utilization?

·        (a-v)O2 diff

17. How do SBP and DBP change with aerobic exercise?

·        DBP stays the same and SBP increases

18. What is the rate-pressure product?

·        HR*SBP

·        Related to myocardial O2 uptake and myocardial blood flow

19. What is a primary factor that triggers increased blood flow to working muscles? (local)

·        They have greatest metabolic need

20. Why does skin blood flow change as core temperature increases?

·        To expel heat from the body

21. Be able to define cardiovascular drift.

·        Heart rate increases despite constant workload

22. What is a possible cause of cardiovascular drift?

·        Increase core temp and dehydration

25. What is a-vO₂difference?  How does it change as an individual goes from rest to exercise?

·        Dfference in O2 concentration in the arteries and veins

·        It increases from rest to exercise because more O2 is utilized by the muscles

26. A decrease in plasma volume results in “hemoconcentration.”  Be able to explain this concept.

·        Fluid percent of blood is lower than usually causing the cell percent to be higher than normal

o   Increase RBC

o   Increase hemoglobin concentration

o   Increase O2 carrying capacity

·        Hematocrit increases up to 50%+

27. What is dyspnea?

·        Shortness of breath

28. How does blood PCO₂ affect ventilation?

·        Increases it, drives ventilation

29. What is the Valsalva maneuver?  Is it safe? 

·        Applying force to a closed glottis

·        It’s safe for the majority but should be avoided for beginner lifters and people with hypertension

30. What is a benefit of performing the Valsalva maneuver?

·        Increase in force production

5 - Be able to graph HR and SV response to incremental exercise, from rest up to maximal effort 
12 - Be able to graph Q during incremental exercise, up to maximal effort. 
13 - What is responsible for the increase in Q above 50% VO₂max?

·        HR and workload = linear relationship

·        SV and workload = maximizes about 50% and plateaus

·        Q and workload = HR responsible for Q increase second half exercise