Lecture 20

Question 1

What are the 3 major CV adjustments to exercise?

Answer 1

1.) Cardiac Output
2.) Q redistributed through body
3.) Tissue rate of 02 removal from blood

Question 2

What is blood pressure?

Answer 2

The average force exerted by the blood against vasculature (mmHg)

Question 3

What are the primary determinants of blood pressure? 

Answer 3

1.) Cardiac output
2.) Peripheral resistance (vasoconstriction and vasodilation)

Question 4

Describe the pathway of blood, moving through the vasculature 

Answer 4

Blood leaves heart > aorta > large arteries > arterioles > capillaries > veins > vena cava back to heart

Question 5

Is blood pressure linear?

Answer 5

 Where are the waves of blood, pressure pressure fluctuates and falls as it moves away from the heart and back

Question 6

Why doesn’t it take much pressure to overcome pressure in the veins for the muscle pump effect?

Answer 6

Pressure of the system falls as it moves away from the heart which means pressure is low on the venous side.

Question 7

What tools do you need to measure blood pressure?

Answer 7

A stethoscope and a measurement device for pressure like a mercury gage

Question 8

Describe the first step for measuring blood pressure:

Answer 8

• blood pressure cuff placed around the brachial artery (easier to access, could do other locations though)
• flow is laminar
• no sounds

Question 9

Describe the second step for measuring blood pressure

Answer 9

• 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

Question 10

Describe the third step for measuring blood pressure

Answer 10

• Start to slowly deflate the cuff, pressure falls
• Eventually blood starts to flow through. This is the first Korotkoff sound (systolic blood pressure!)

Question 11

Describe the fourth and last step for measuring blood pressure

Answer 11

• keep slowly deflating the cuff until sounds disappear
• For a healthy person at rest this is usually around 80 mmHg (Diastolic blood pressure!)

Question 12

Define mean arterial pressure

Answer 12

The average driving pressure during the cardiac cycle

Question 13

What’s the equation for mean arterial pressure? Why is it expressed this way?

Answer 13

MAP = DBP + [1/3 (SBP -DBP)]

• expressed this way because we spend less time in systole

Question 14

What do you call systolic blood pressure minus diastolic blood pressure?

Answer 14

Pulse pressure

Question 15

What’s a reasonable value for resting mean arterial pressure and why?

Answer 15

93

MAP = 80 + (1/3 (120-80))
= 93

Question 16

What are the three different types of high blood pressure you can have?

Answer 16

High diastolic, systolic or mean arterial

Question 17

What’s a reason for high diastolic blood pressure?

Answer 17

Vascular issues that caused an increased resistance to blood flow like atherosclerosis

Question 18

What happens to diastolic blood pressure during dynamic exercise?

Answer 18

Ideally, we don’t see much of a change in diastolic blood pressure

-Drop is okay, rise suggests that peripheral resistance is increasing somehow

Question 19

What happens to systolic blood pressure during dynamic exercise?

Answer 19

Systolic blood pressure rises
(Ex. If you started at 120 you might end at 200)

Question 20

What happens to mean arterial blood pressure during dynamic exercise and why?

Answer 20

Can you see a small increase, this is mostly influenced by systolic blood pressure since diastolic is not changing

Question 21

What happens to systolic diastolic and mean arterial blood pressure during resistance exercise?

Answer 21

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)

Question 22

What is the Valsalva Maneuver? Why is this useful? How does it affect blood pressure?

Answer 22

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

Question 23

Why am I we see such a big difference in blood pressure between dynamic and resistance exercise?

Answer 23

1.) valsalva maneuver

2.) forces that are generated in the muscle are much bigger than dynamic, this collapses arteries and includes blood flow.

Question 24

When might weightlifting be bad?

Answer 24

• 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)

Question 25

What is the double product?

Answer 25

• An index of cardiac work

DP = HR x SBP (easily measured values!)

Question 26

What’s a reasonable value for a double product and its components during dynamic exercise in a healthy person?

Answer 26

DP = 21,000
HR = 140
SBP = 150

Question 27

I what’s the reasonable value for double product and is components in someone who is hypertensive for dynamic exercise?

Answer 27

DP = 28,000
HR = 140
SBP = 200

Question 28

What’s a reasonable value for a double product in a healthy person during resistance exercise?

Answer 28

DP = 56,000
HR = 140
SBP = 400

Question 29

What is a stolen blood pressure how much higher in a hypertensive individuals? (During dynamic exercise)

Answer 29

How far it has to work a lot harder (150>200, 30% increase from normal dynamic exercise, blood pressure)

Question 30

What determines blood flow (ie. cardiac output)? Hint: equation

Answer 30

Pressure difference (mean arterial pressure) over resistance (total peripheral resistance)

• thus, cardiac output, can either increase with increase in pressure or decrease resistance

Question 31

What other equation can describe cardiac output?

Answer 31

Q = MAP / TPR

Or

TPR = MAP / Q

mean arterial pressure, total peripheral resistance

Question 32

What are reasonable values for a cardiac output, mean arterial pressure and total peripheral resistance at rest?

Answer 32

Q = 5 l/min
MAP = 93 mmHg
TPR = 19 mmHg/l/min

Question 33

Reasonable values for cardiac output, mean arterial pressure and total peripheral resistance during heavy exercise?

Answer 33

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

Question 34

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?

Answer 34

Q = increase 5x
MAP = increase by 30%
TPR = decrease 4x

Question 35

Why might a bigger than normal drop in resistance be a bad thing?

Answer 35

• 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)

Question 36

What happens in active muscle to increase muscle blood flow so much during exercise?

Answer 36

• vasodilation
• decreased resistance
  =more blood flow!
• hello this to happen we need vasoconstriction in other areas

Question 37

What happened to nonactive tissues for blood flow to increase so much during exercise?

Answer 37

• vasoconstriction
• increased resistance
  = less blood flow