Exercise and Cardiovascular System Flashcards
What controls HR?
SA node and automaticity
What is steady state and when is it typically reached?
optimal HR for a given workload (HR should flatten out)
1-2min
What is training effect?
heart rate will be less same workload over time
*don’t make goals for this bc many factors play a role
How do you calculate HRMax
220 - age
low-level stress test __%HRMax
sub-max stress test __%HRMax
75%
85%
What is stroke volume?
The amount of blood pumped out of the ventricle each cardiac cycle or heart beat
How do you calculate stroke volume?
SV = End diastolic volume - End systolic volume
SV = EDV - ESV
What is end diastolic volume and end systolic volume
EDV = how much is in ventricles during filling
ESV = how much is remaining
What is the relationship between preload (how much blood is in the heart), EDV, and SV
inc preload –> inc EDV –> ESV
more tension = more blood out
What is the relationship between afterload, ESV, and SV
(afterload is the pressure the ventricles need to over come in oder to eject blood)
Inc after-load –> inc ESV –> dec SV
___ is the pressure the ventricles need to over come in oder to eject blood
After-load
Intrinsic and Extrinsic factors that influence contractility
intrinsic - myocardial stretch (EDV)
extrinsic - sympathetic stimulation (epinephrine)
How does our body do venous return
gastroc - walking
one way valves up legs
respiratory pump - ICV passes through diaphragm
What happens to stroke volume as venous return increases? why?
increases because there is more blood to be pumped in and out
What is normal stroke volume? how does it change if you are an athlete
70 ml/beat
increases if you are an athlete
What is cardiac output
volume of blood pumped out per min
how do you calculate cardiac output?
CO (Q) = HR x SV
2 people with 50 bpm and 80bpm both have a Qrest = 5.04 l/min.
How does stroke volume influence cardiac output at rest?
higher stroke volume = less bpm bc heart is more efficient
lower stroke volume = more bpm bc heart is less efficient
to maintain 5l/min CO, what happens to HR and SV when:
dec sympathetic stim to heart
inc HR and dec SV
to maintain 5l/min CO, what happens to HR and SV when:
inc parasympatheitc stim to heart
dec HR and inc SV
to maintain 5l/min CO, what happens to HR and SV when:
inc venous return
dec HR and inc SV
to maintain 5l/min CO, what happens to HR and SV when:
dec EDV
inc HR and dec SV
to maintain 5l/min CO, what happens to HR and SV when:
dec blood volume
inc HR and dec SV
What happens to HR and SV when CO increases during exercise
HR and SV increase
What is ejection fraction
the percentage of ventricular filling that is ejected with each heart beat
How do you calculate ejection fraction?
EF = SV / EDV
SV = (EDV - ESV)
What is a normal ejection fraction
What percentage is indicative of heart failure
60-70%
<40%
What happens to SBP during exercise, why?
increases because blood is being pumped more quickly causing more pressure
What are some reasons for concern with SBP and exercise
SBP doesn’t rise
drop >10mmHg
extertional hypotension (drop >20mmHg)
What is normal and abnormal DBP response during exercise
norm: unchanged or slight decrease
abnormal: >90mmHg or increase >10mmHg
What is the relationship between pulse pressure and exercise
how do you calculate PP
PP = SBP - DBP
widens with inc workload
What is narrowing and excessive widening of PP a sign of
narrowing - inotropic incompetence or decrease contractility
excessive widening - arteriosclerosis or systolic hypertension
What is Mean Arterial Pressure (MAP), what is the norm
average pressure in arteries over one cardiac cycle
70 mmHg
How do you calculate MAP
MAP = DBP + .33(pulse pressure)
pulse pressure = sys - dys
What is Rate Pressure Product and how do you calculate
indicator of myocardial O2 demand
RPP = SBP x HR
what are you at risk of if RPP is above norm (20,000 - 40,000)
ischemia
Endurance is looking at delivery of blood and utilization (O2 used by tissues) of blood. How is utilization measured
a - vo2 diff
arterial - venous difference
How do you measure oxygen consumption? (VO2)
V02 = HR x SV x (a-vO2 diff)
How do you measure O2 consumption with central and peripheral
central: CO = HR x SV
peripheral: A - VO2 differance
what is resting O2 consumption (approx)
250ml/min
__ml/kg/min = 1 MET
3.5
