Flashcards in Exercise Physiology Deck (62):
What is the equation for SV?
SV = EDV - ESV
What is the equation for MAP?
CO x TPR
What is the equation for VO2?
CO x avO2 diff
What are the effects of the SNS with exercise?
Increases HR, contractility, and TPR
What is the limiting factor of exercise, normally?
What are the three factors of CO that the SNS affects?
Why does SNS activity increase with exercise?
Resetting the baroreflex set point to a higher pressure d/t changes in the central command and the exercise pressor reflex
How is the baroreceptor reflex controlled? (3)
-Mechanoreceptors in the heart
-Exercise pressor reflex
What are the two receptors that are responsible for baroreceptor resetting via the exercise pressor reflex?
What is the feedforward mechanism of SNS?
Central command increases SNS
What is the feedback mechanism of the SNS during exercise?
Exercise pressor reflex
What is the effect of the SNS on nerve activity with a drop in arterial pressure? Sudden increase?
-Inhibit the vagus if drops
-Stimulate if increases
What happens to SNS activity with increased BP? When in the cardiac cycle do these bursts occurs?
When pressure drops during diastole
Where does arterial constriction occur at to increase TPR? (3)
What is the central command bit of BP regulation? What does this do?
Higher CNS areas that operate in anticipatory phase of exercise and during exercise
Increases SNS output with increased alpha motor neuron output
What are the three areas that are affected with increased activity of "central command"?
What are the nerves that relay the exercise pressor reflex?
Grp III = mechanoreflex
Grp IV = Metaboreflex
What is the effector part of the exercise pressor reflex? What is the integration site?
What are the two variables sensed with the exercise pressor reflex?
-Metaboreflex (VD metabolites)
-Mechanoreflex (speed and force of contraction)
What happens to the distribution of blood with increasing intensity of exercise?
Redistributes more to the muscles
What percent of flow can be redirected to muscle during exercise?
What is the normal CO during rest? Exercise in an athlete?
40L/min in an athlete
What allows vasodilation of the muscles despite SNS activity telling it to constrict?
Metabolic autoregulation--accumulation of VD metabolites increase during exercise, causing vasodilation
What are the two places in the body that are not affected with constrictive SNS activity?
What happens to SBP and DBP as exercise intensity increases?
-DBP stays constant, or lowers
What causes the drop in DBP with exercise?
Muscular vasodilation causes a drop in TPR
SBP rises in proportion to what?
What happens to DBP with resistance exercises?
Increased TPR d/t resistance to flow in the muscles
What is the relative increase in BP and HR with arm exercise compared to leg? What is the significance of this?
Arm causes a higher increase in HR and BP
MIs frequently occur with arm exercise
What is the range of average VO2max?
30s, with higher being better
What is the VO2max that indicates difficulties with ADLs?
What are METs?
x resting VO2
What is the relation between HR and work rate?
Will increase in similar amounts.
What is the use of submaximal tests or walking tests?
Increase in distance for a 6 min walk test
What is the equation for VO2?
HR x SV x avgO2 diff
What causes the increase in HR with exercise?
Vagal withdrawal, increases in SNS
What is the max HR equation?
208- (0.7 x age)
Why does stroke volume increase with exercise? (3)
-Increased venous return
-SNA on cardiac muscle (Ca)
What is the Ca induced Ca release model of cardiac myocytes?
Increase in Ca from SNS increase, increases contractility
What is avO2 difference?
Difference between the oxygen content in arterial blood and venous blood
Why does the avO2 difference increase with exercise? (2)
-Redistribution of flow to active tissues during exercise
-Rightward shift of oxyhemoglobin dissociation curve
What happens to the hypothalamic set point with increased heat with exercise?
No change in the set point, but still regulated
What is the compensatory response to increased heat generation? How?
Cutaneous vasodilation d/t dual innervation of the SNS
What are the four responses to cold?
What are the two major responses to increased heat?
-sweating and evaporation
True or false: skin competes with muscle for flow during exercise
What does it mean that skin is a compliant circulation?
Readily changes circulation with temperature changes
Why is heating a cardiac strain?
Blood is shunted into skin, meaning more CO is needed to maintain homeostasis
What happens to SV with prolonged sweating from exercise? How is this compensated for?
Drops d/t dehydration
What is the MOA of heat related stress problems?
Decreased SV causes problems if heart has issues increasing rates
What is phase I of integrated regulation during exercise?
Central command increases ventilatory rate
What is phase II of integrated regulation during exercise?
Ve rises to reach steady state
Lactate accumulation in exercise is due to what?
Inability to remove it
What is the LT?
Point at which lactate accumulates within the blood
What is the VT?
VE/VO2 relationship departs from linearity
What happens physiologically with exercise training?
Better at extracting the O2, so decreased muscle blood flow spares blood for thermoregulation
What are the metabolic adaptations to training? (5)
-Increased mitochondrial response
-Glucose sparing effect
-Blood lactate clearance
What are the GLUT transporters that are increased with exercise?
What does it mean that exercise is a natural insulin?
Will cause an increase in GLUT4
What are the two primary controllers of ventilatory rate?
CO2 and pH
What happens in phase III of ventilation during exercise?
Fine tuning through peripheral feedback