Cardio 10 Flashcards
What happens to HR during exercise? How much does it change? Why?
HR increases, proportional to work and can change by 3x or more
HR increases due to increase in SANS tone and decreases in PANS tone
Describe the change in SV during exercise. Why does it have this shape?
SV increases a little and dips
-The increase in sympathetic activity increases contractibility resulting in an initially higher SV
-The dip at the end is due to increased HR/AP in a given time, which means the filling time is decreased, and by the FS mechanism, SV is slightly lower
Describe the change in CO during exercise. Why does it have this shape? How much does it increase why?
There is a linear increase in CO due to SV and HR. It mostly depends on HR because SV does not move much
It increases 3x for CO because HR increases 3x
At what levels of HR would CO not increase as much during exercise?
Since SV drops at very high HR, CO will no increase as much for very high HR
REMINDER: what will make CO change?
The SANS will stimulate the adrenal gland, releasing E and affecting the SA node to increase HR as well as cardiac muscles to increase contractibility
Describe the change in cardiac pressure during exercise.
MAP is stable throughout exercise, it increases 1.2X
SYSTOLIC: Increases a lot
DIASTOLIC: Increases just a bit
By looking at the MAP formula and variables, why does MAP increase 1.2x, but CO increases 3x?
Because TPR drops dramatically during exercise
Why does TRP decrease dramatically during exercise?
The muscles consume more O2 and generate waste products, activating a metabolic auto-regulation
Describe the change in O2 consumption during exercise.
It rises by about 9x because the gradient at cells is greater
By following Fick’s principle, O2 uptake must equal O2 consumption
Which measure is the most relevant during exercise? why?
MAP because it drives perfusion
How does blood flow vary in the body during exercise
Increases the most in muscles
Increases in muscle
Large increase in skin
Increase to heart
EVERYWHERE ELSE: flow drops to compensate
Is there a difference in flow changes in a trained and an untrained individual?
Trained: flow can increase 7x
Untrained: flow can increase 3.5x
During exercise, there are many competing effects: NE, E and waste. What happens in EXERCISING MUSCLES?
the local metabolic control will override the other inputs of the sympathetic system during exercise
T or F
Training affects maximum heart rate. Explain your answer
F
Contractibility is increased for a heart can get more efficient (increasing CO and SV with training) but cannot beat more per minute.
What are the consequences of increased contractibility due to exercise?
- Hypertrophy –> bigger SV but also more chances of arrhythmias
- RESTING HR drops (not max HR increases)
