Exercise and Shock Flashcards
Is homeostasis disrupted during exercise?
Yes, and the body must make adjustments
What is VO2?
Oxygen consumption
Is maximum HR a function of age or training?
Age
Does HR increase linearly with exercise?
Yes
SV ____ at low intensity, but _____ at highest work loads
Increases, plateaus
What causes the plateau in SV at high intensity exercise?
Reduced ventricular filling time
What is the a-v difference?
It is the difference between the volume percent of blood that is O2 when it leaves the heart vs when it returns to the heart.
(Ex: at rest, it is usually 20% O2 by volume when it leaves the heart, and it is 15% O2 when it returns to the heart)
What does exercise do to a-v difference?
It increases it
More O2 gets transferred to the tissues
At rest, skeletal muscle receives 20% of CO. What happens during exercise’
Blood gets redistributed to the muslce and skin at the expense of the viscera (May gets up to 85% of CO)
Does blood ever get redirected away from the heart and brain during exercise in order to supply the muscle?
No, it will actually increase
Why does the skin get more blood flow during exercise
So that we can release heat
What effect does exercise have on TPR?
It drops! This is becasue the skeletal muscles are vasodilated due to all the local metabolites they release
As metabolic rate increases, TPR ______
Decreases
Exercise causes decreased TPR, but MAP increases! Why?
Due to the increased CO
MAP= CO x TPR
What happens to diastolic pressure during exercise?
Doesn’t change much
What happens to systolic and MAP during exercise?
Increase
Why does diastolic pressure stay the same during exercise? Increased HR should increase DP due to less time for runoff between beats!
The decreased TPR cancels out the effects of the increased HR, so DP stays about the same
What happens to resting HR in a trained athlete?
Decreases due to greater vagal tone and reduced SNS tone
If resting HR is lower in trained athletes, does their CO decrease?
No, it is maintained by an increased SV
Why does endurance training increase stroke volume both at rest and during exercise?
Increased heart size
Decreased HR which allows for greater filling
Increased contractility due to enhanced Ca++ release
What happens to total blood volume with endurance training?
Increases
Why does total blood volume increase in trained athletes ?
Increase in plasma volume
+minor increases in cell volume
Why would a trained athlete have a LOWER hematocrit than a nontrained person?
They have increased plasma volume, so therefore the percent of their blood that is RBCs is decreased
What is the benefit for trained athletes to have increased blood volume if its just plasma?
It provides cardiovascular stability during exercise:
-reduces cardiovascular drift
-fluid volume lost through sweat doesn’t impact venous return too much
Sweatinf during exercise has what effect on venous return?
Decreases venous return which reduces SV, and HR must increase even more to maintain CO
(Trained athletes with more plasma will be affected by this less)
Who will have a higher VO2 max and CO: sedentary person or athlete?
Athlete
How do people’s bodies acclimatize to high altitudes?
Respiratory: hyperventilation
Circulatory: polycythemia and an increase in 2,3 DPG in RBCs
What does 2,3 DPG do?
It enhances unloading of O2 in tissues
Decreases Hb’s affinity for O2
Who has lots of 2,3 DPG
People at high altitudes
What causes an increased RBC concentration in the blood?
EPO release by the kidney