Exercise Physiology

Question 1

What is the equation for SV?

Answer 1

SV = EDV - ESV

Question 2

What is the equation for MAP?

Answer 2

CO x TPR

Question 3

What is the equation for VO2?

Answer 3

CO x avO2 diff

Question 4

What are the effects of the SNS with exercise?

Answer 4

Increases HR, contractility, and TPR

Question 5

What is the limiting factor of exercise, normally?

Answer 5

cardiac output

Question 6

What are the three factors of CO that the SNS affects?

Answer 6

HR
TPR
Contractility

Question 7

Why does SNS activity increase with exercise?

Answer 7

Resetting the baroreflex set point to a higher pressure d/t changes in the central command and the exercise pressor reflex

Question 8

How is the baroreceptor reflex controlled? (3)

Answer 8

• Mechanoreceptors in the heart
• central command
• Exercise pressor reflex

Question 9

What are the two receptors that are responsible for baroreceptor resetting via the exercise pressor reflex?

Answer 9

Mechanoreceptors

Metaboreceptors

Question 10

What is the feedforward mechanism of SNS?

Answer 10

Central command increases SNS

Question 11

What is the feedback mechanism of the SNS during exercise?

Answer 11

Exercise pressor reflex

Question 12

What is the effect of the SNS on nerve activity with a drop in arterial pressure? Sudden increase?

Answer 12

• Inhibit the vagus if drops

- Stimulate if increases

Question 13

What happens to SNS activity with increased BP? When in the cardiac cycle do these bursts occurs?

Answer 13

Increased discharge

When pressure drops during diastole

Question 14

Where does arterial constriction occur at to increase TPR? (3)

Answer 14

Skin
Muscle
Kidney

Question 15

What is the central command bit of BP regulation? What does this do?

Answer 15

Higher CNS areas that operate in anticipatory phase of exercise and during exercise

Increases SNS output with increased alpha motor neuron output

Question 16

What are the three areas that are affected with increased activity of “central command”?

Answer 16

Skeletal muscles
CV system
Respiratory system

Question 17

What are the nerves that relay the exercise pressor reflex?

Answer 17

Grp III = mechanoreflex

Grp IV = Metaboreflex

Question 18

What is the effector part of the exercise pressor reflex? What is the integration site?

Answer 18

SNS

CV centers

Question 19

What are the two variables sensed with the exercise pressor reflex?

Answer 19

• Metaboreflex (VD metabolites)

- Mechanoreflex (speed and force of contraction)

Question 20

What happens to the distribution of blood with increasing intensity of exercise?

Answer 20

Redistributes more to the muscles

Question 21

What percent of flow can be redirected to muscle during exercise?

Answer 21

80%

Question 22

What is the normal CO during rest? Exercise in an athlete?

Answer 22

5 L/min

40L/min in an athlete

Question 23

What allows vasodilation of the muscles despite SNS activity telling it to constrict?

Answer 23

Metabolic autoregulation–accumulation of VD metabolites increase during exercise, causing vasodilation

Question 24

What are the two places in the body that are not affected with constrictive SNS activity?

Answer 24

Brain

Coronary vasculature

Question 25

What happens to SBP and DBP as exercise intensity increases?

Answer 25

- SBP increases | - DBP stays constant, or lowers

Question 26

What causes the drop in DBP with exercise?

Answer 26

Muscular vasodilation causes a drop in TPR

Question 27

SBP rises in proportion to what?

Answer 27

Flow

Question 28

What happens to DBP with resistance exercises?

Answer 28

Increased TPR d/t resistance to flow in the muscles

Question 29

What is the relative increase in BP and HR with arm exercise compared to leg? What is the significance of this?

Answer 29

Arm causes a higher increase in HR and BP MIs frequently occur with arm exercise

Question 30

What is the range of average VO2max?

Answer 30

30s, with higher being better

Question 31

What is the VO2max that indicates difficulties with ADLs?

Answer 31

12-14 ml/kg*min

Question 32

What are METs?

Answer 32

x resting VO2

Question 33

What is the relation between HR and work rate?

Answer 33

Will increase in similar amounts.

Question 34

What is the use of submaximal tests or walking tests?

Answer 34

Increase in distance for a 6 min walk test measures improvement

Question 35

What is the equation for VO2?

Answer 35

HR x SV x avgO2 diff

Question 36

What causes the increase in HR with exercise?

Answer 36

Vagal withdrawal, increases in SNS

Question 37

What is the max HR equation?

Answer 37

208- (0.7 x age)

Question 38

Why does stroke volume increase with exercise? (3)

Answer 38

- Increased venous return - SNA on cardiac muscle (Ca) - Decreased TPR

Question 39

What is the Ca induced Ca release model of cardiac myocytes?

Answer 39

Increase in Ca from SNS increase, increases contractility

Question 40

What is avO2 difference?

Answer 40

Difference between the oxygen content in arterial blood and venous blood

Question 41

Why does the avO2 difference increase with exercise? (2)

Answer 41

- Redistribution of flow to active tissues during exercise | - Rightward shift of oxyhemoglobin dissociation curve

Question 42

What happens to the hypothalamic set point with increased heat with exercise?

Answer 42

No change in the set point, but still regulated

Question 43

What is the compensatory response to increased heat generation? How?

Answer 43

Cutaneous vasodilation d/t dual innervation of the SNS

Question 44

What are the four responses to cold?

Answer 44

- Cutaneous vasoconstriction - Piloerection - Shivering - Increased thermogenesis

Question 45

What are the two major responses to increased heat?

Answer 45

- Cutaneous vasodilation | - sweating and evaporation

Question 46

True or false: skin competes with muscle for flow during exercise

Answer 46

True

Question 47

What does it mean that skin is a compliant circulation?

Answer 47

Readily changes circulation with temperature changes

Question 48

Why is heating a cardiac strain?

Answer 48

Blood is shunted into skin, meaning more CO is needed to maintain homeostasis

Question 49

What happens to SV with prolonged sweating from exercise? How is this compensated for?

Answer 49

Drops d/t dehydration | Increases HR

Question 50

What is the MOA of heat related stress problems?

Answer 50

Decreased SV causes problems if heart has issues increasing rates

Question 51

What is phase I of integrated regulation during exercise?

Answer 51

Central command increases ventilatory rate

Question 52

What is phase II of integrated regulation during exercise?

Answer 52

Ve rises to reach steady state

Question 53

Lactate accumulation in exercise is due to what?

Answer 53

Inability to remove it

Question 54

What is the LT?

Answer 54

Point at which lactate accumulates within the blood

Question 55

What is the VT?

Answer 55

VE/VO2 relationship departs from linearity

Question 56

What happens physiologically with exercise training?

Answer 56

Better at extracting the O2, so decreased muscle blood flow spares blood for thermoregulation

Question 57

What are the metabolic adaptations to training? (5)

Answer 57

- Increased mitochondrial response - Capillary density - Glucose sparing effect - Blood lactate clearance - Insulin sensitivity

Question 58

What are the GLUT transporters that are increased with exercise?

Answer 58

GLUT4

Question 59

What does it mean that exercise is a natural insulin?

Answer 59

Will cause an increase in GLUT4

Question 60

What are the two primary controllers of ventilatory rate?

Answer 60

CO2 and pH

Question 61

What happens in phase III of ventilation during exercise?

Answer 61

Fine tuning through peripheral feedback

Question 62

What happens in the recovery phase of ventilation regulation?

Answer 62

Abrupt loss of central command and peripheral muscle causes drop in ventilation