lab 8 Flashcards
an increase in cardiorespiratory function reduces what
risk of chronic diseases and death
What do cardiac and hemodynamic (BP) assessments during exercise do that VO2 max doesnt show
provides more sensitive measurement of changes in cardiorespiratory function
the purpose of using a graded exercise test depends on what
depends on the person being tested
why does the reason for using a GXT change with different people
- research utilize GXT for young, healthy individual to measure changes in cardiorespiratroy function before and after a training program
- for a 60 year old w/ multiple risk factors = diagnostic for heart disease
Common measurements for all GXT procedures include what 4 things
- cardiac electrical conuction through 12 lead ECG, ratings of perceived exertion (RPE), oxygen consumption, and BP
What is the most valuable measurement and indicator of cardiovascular health
BP
What is blood pressure
ratio of systolic pressure and diastolic pressure
BP = sBP/dBP
what is systolic blood pressure
pressure in the arteries when the heart contracts
Diastolic pressure is what
pressure in the arteries when the heart is filling between beats
what is pulse pressure (PP)
difference between diastolic and systolic pressures
PP= sBP-dBP
What is a healthy BP
120/80
What is MAP
average pressure in the arteries during a cardiac cycle
map determines what
rate of blood flow through vasculature
MAP is equal to what at rest (what is the equation)
MAP = dBP + 1/3PP
- calculated this way b/c heart is in diastole for 2/3 of cardiac cycle at rest
- this measurement loses accuracy during exercise b/c heart is in systole (contractiorest to ) for relatively greater amount of time compared
MAP is determined by what two things during exercise
cardiac output (Q) and total peripheral resistance (TPR)
MAP = Q * TPR
What is TPR
sum of resistance to blood flow in the vasculature
* bp is influenced by anything that influences Q or TPR
Explain the whole pathway on why BP increases with exercise
- due to lg increase in cardiac output
- elevated HR and L ventricular contractility b/c sympathetic activity and increase in venous return (preload), increase cardiac output
MAP (afterload) does what to the heart
is a barrier to the ejection of blood from the ventricles –> make stroke volume increase more than blood pressure to pump blood into body
vasodilation of the arterioles supplying blood to active muscles does what
helps reduce the increase in afterload during exercsie
what is the net result of exercise on BP causes what
increase in systolic BP due to increase Q, while diastolic BP doesnt change or decreases slightly
aerobic exercise training does what do resting and submaximal exercise BP
decreases resting and submax exercise BP
- resting and submax HR decrease, vascular tone (TPR) diminish
at max exercise what happens to BP
diastolic BP changes but systolic BP and MAP dont change
reasons for performing a GXT include what 5 things
- medical history and physical
- evaluating exertional discomfort
- evaluating presence of hidden CAD
- classifying risk patients w/ known cardiovascular disease
- prescribing exercise
Before the GXT subjects are classified into what risk groups
- age
- known disease
- risk factors
Following screening what is recorded
resting HR and BP == test begins at given work rate
when is the test stopped
either at predetermined point (given % or HRmax) or point of volitional exhaustion
The criteria for test termination can be what two things
- absolute (always stopped)
- relative (subject to discretion)
why are GXTs useul in measureing changs in cardiac function
b/c many cardiovascular and physioogical abnormalities dont become apparent until the body is stressed
What are 3 general indications for stopping an exercise test in low risk
- onset of angina or angina-like symptoms
- subject requests to stop
- failure of HR to increase w/ increased exercise intensity
changes in cardiac function during graded exercise does what to the graph
linear increase in HR to max — and linear increase in SV until certain intensity
- SV plateus at about 50% in untrained individuals
- in trained = SV plateaus at much greater intensities or may not plateau
What happens to cardiac output and SV with graded exercise
Q increases greatly at first and the less as SV plateaus
an Electrocardiogram (ECG) is used to do what
used as indicator of heart’s ability to function normally under inccreased myocardial oxygen demand
What things are altered with an increase HR during exercise that are normal and reduced RR intervals
Altered:
1. Action potential duration
2. conduction velocity
3. Contractile velocity
- also have minor QRS complex and P wave changes
The information from a GXT test is more important in doing what
defining risk and predicting future problems than making specific diagnosis
the prognostic capabilities of a GXT are defined as what
as “normal” and “abnormal” cardiac and hemodynamic changes
what is the best predictor of cardiovascular function
VO2
Explain the cardiovascular responses to exercise w/ BP, a-v O2 difference, SV, and Q
- BP == systolic increases linearly, diastolic stays constant
- a-v O2 diff == increases sharply and then increases as a smaller slope
- SV == increases sharply and then plateus
- Q == increases sharply and then increases as a smaller slope
Explain the BP response to graded exercise
- with exercise systolic gradually increases then at rest slowly decreases
- diastolic doesnt change
a S-T depression means what
myocardial ischemia – partial or complete blockage of coronary artery
what is the name of the sound that is your systolic BP
Korotkoff sound
