malinda
Forum Guru
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How does heart adapt during exercise...from the point where a person starts exercise ...then in the middle .I mean moderate to sternous exercise..I am asking in terms of HR and SV plz
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| skyhigh
Forum Guru
Topics: 105
Posts: 561
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initially there is vasodilation b/c of dec. TPR, then there is increased SV AND HR, but can some explain mechanism plz.
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| skyhigh
Forum Guru
Topics: 105
Posts: 561
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what happens to arterial and venous oxygen during exercise?
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| abarbaryan
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During exercise the heart adapts through the inc symp outflow to the heart and blood vessels and dec parasym outflow to the heart. These results in the following
- Inc in HR (via beta1 receptors and dec activity of PANS)
- Inc in SV (inc contractility again via beta1 receptors)
Together, they produce an increase in CO which is important in the response to exercise.
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| mjl1717
Forum Hero
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I believe adenosine and possibly NO2 are some of the natural metabolites that assists in the initial vasodilation {This probably a good q to answer together]
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| abarbaryan
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At rest blood flow to skeletal muscle is regulated mainly by symp nerve fibers which are vasoconstricting (alfa1 receptors), of course there are also beta2 receptors (vasodilation)activated by epinephrin which is released from adrenal gland during the exercise or during the fight-or-flight response.
So, what about blood flow during exercise. You are right during exercise blood flow is primarily controled by local metabolites (lactate.adenosin,potassium (truly speaking I have never heard about NO2 as a local vasodilator in muscle vasculature)) which result in the overall decrease in TPR. Other locations where vasoconstriction doesn't occur are in the coronary circulation and the cerebral circulation unlike vessels of splanchic region and kidney which are under the control of SANS (vasoconstriction).
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