Lecture 20 Flashcards
What are the 3 major CV adjustments to exercise?
1.) Cardiac Output
2.) Q redistributed through body
3.) Tissue rate of 02 removal from blood
What is blood pressure?
The average force exerted by the blood against vasculature (mmHg)
What are the primary determinants of blood pressure? 
1.) Cardiac output
2.) Peripheral resistance (vasoconstriction and vasodilation)
Describe the pathway of blood, moving through the vasculature 
Blood leaves heart > aorta > large arteries > arterioles > capillaries > veins > vena cava back to heart
Is blood pressure linear?
 Where are the waves of blood, pressure pressure fluctuates and falls as it moves away from the heart and back
Why doesn’t it take much pressure to overcome pressure in the veins for the muscle pump effect?
Pressure of the system falls as it moves away from the heart which means pressure is low on the venous side.
What tools do you need to measure blood pressure?
A stethoscope and a measurement device for pressure like a mercury gage
Describe the first step for measuring blood pressure:
- blood pressure cuff placed around the brachial artery (easier to access, could do other locations though)
- flow is laminar
- no sounds
Describe the second step for measuring blood pressure
- inflate the cuff to a sufficient pressure to collapse the artery, blood fully occluded
- at rest getting it to 140 mmHg is enough (exercise/unhealthy = higher BP)
- no sounds
Describe the third step for measuring blood pressure
- Start to slowly deflate the cuff, pressure falls
- Eventually blood starts to flow through. This is the first Korotkoff sound (systolic blood pressure!)
Describe the fourth and last step for measuring blood pressure
- keep slowly deflating the cuff until sounds disappear
- For a healthy person at rest this is usually around 80 mmHg (Diastolic blood pressure!)
Define mean arterial pressure
The average driving pressure during the cardiac cycle
What’s the equation for mean arterial pressure? Why is it expressed this way?
MAP = DBP + [1/3 (SBP -DBP)]
- expressed this way because we spend less time in systole
What do you call systolic blood pressure minus diastolic blood pressure?
Pulse pressure
What’s a reasonable value for resting mean arterial pressure and why?
93
MAP = 80 + (1/3 (120-80))
= 93
What are the three different types of high blood pressure you can have?
High diastolic, systolic or mean arterial
What’s a reason for high diastolic blood pressure?
Vascular issues that caused an increased resistance to blood flow like atherosclerosis
What happens to diastolic blood pressure during dynamic exercise?
Ideally, we don’t see much of a change in diastolic blood pressure
-Drop is okay, rise suggests that peripheral resistance is increasing somehow
What happens to systolic blood pressure during dynamic exercise?
Systolic blood pressure rises
(Ex. If you started at 120 you might end at 200)
What happens to mean arterial blood pressure during dynamic exercise and why?
Can you see a small increase, this is mostly influenced by systolic blood pressure since diastolic is not changing
What happens to systolic diastolic and mean arterial blood pressure during resistance exercise?
We see a very large increase in all of these
- (systolic can have values all the way up to 300 mmHg and mean arterial pressure and diastolic blood pressure light in between 200 and 300 usually)
What is the Valsalva Maneuver? Why is this useful? How does it affect blood pressure?
A forced exhale across a closed glottis (holding breath when picking something up)
- increases thoracic pressure to stabilize spine and reduce injury
- Drives up blood pressure
Why am I we see such a big difference in blood pressure between dynamic and resistance exercise?
1.) valsalva maneuver
2.) forces that are generated in the muscle are much bigger than dynamic, this collapses arteries and includes blood flow.
When might weightlifting be bad?
- someone who only does this may have bad aerobic fitness
- this may increase the risk of atherosclerosis from increased pressure (this combined might cause an aneurism or stroke)
What is the double product?
- An index of cardiac work
DP = HR x SBP (easily measured values!)
What’s a reasonable value for a double product and its components during dynamic exercise in a healthy person?
DP = 21,000
HR = 140
SBP = 150
I what’s the reasonable value for double product and is components in someone who is hypertensive for dynamic exercise?
DP = 28,000
HR = 140
SBP = 200
What’s a reasonable value for a double product in a healthy person during resistance exercise?
DP = 56,000
HR = 140
SBP = 400
What is a stolen blood pressure how much higher in a hypertensive individuals? (During dynamic exercise)
How far it has to work a lot harder (150>200, 30% increase from normal dynamic exercise, blood pressure)
What determines blood flow (ie. cardiac output)? Hint: equation
Pressure difference (mean arterial pressure) over resistance (total peripheral resistance)
- thus, cardiac output, can either increase with increase in pressure or decrease resistance
What other equation can describe cardiac output?
Q = MAP / TPR
Or
TPR = MAP / Q
mean arterial pressure, total peripheral resistance
What are reasonable values for a cardiac output, mean arterial pressure and total peripheral resistance at rest?
Q = 5 l/min
MAP = 93 mmHg
TPR = 19 mmHg/l/min
Reasonable values for cardiac output, mean arterial pressure and total peripheral resistance during heavy exercise?
Q = 25 l/min
MAP = 120 mmHg
TPR = 5 mmHg/l/min
* TPR decreases several fold!
* Increase in cardiac output during exercise is due more to decreased resistance than increased pressure
Expressed as a relative change or a percent, how does cardiac output, mean arterial pressure and total peripheral resistance increase or decrease in rest versus exercise?
Q = increase 5x
MAP = increase by 30%
TPR = decrease 4x
Why might a bigger than normal drop in resistance be a bad thing?
- faster blood flow means tissues are not getting enough blood
- maintain pressure, cardiac output needs to increase, but at a point we can’t sustain cardiac output and faint (massive dilation of blood vessels but blood can’t keep up)
What happens in active muscle to increase muscle blood flow so much during exercise?
- vasodilation
- decreased resistance
=more blood flow! - hello this to happen we need vasoconstriction in other areas
What happened to nonactive tissues for blood flow to increase so much during exercise?
- vasoconstriction
- increased resistance
= less blood flow
