Lecture 13 Flashcards
What does the maximal oxygen uptake indicate about a person?
Maximal oxygen uptake is the most commonly used measure of cardiorespiratory fitness.
What determines the maximal oxygen uptake?
Maximal oxygen uptake is determined by a combination of genetic endowment (51%) and physical training.(49%)
What is the rate limiting factor for maximal oxygen uptake?
Oxygen delivery is generally considered the rate limiting factor for maximal oxygen uptake.
What happens to VO2 max from aging?
Aging causes a decrease in VO2 max.
What is the frailty threshold?
frailty threshold is the VO2 level at which daily activity becomes difficult.
What are potential limitations to VO2 max?
Ventillation (Diffusion, Hb-O2 affinity)
Central Circulation (Cardiac output, Arterial blood pressure)
Peripheral Circulation (Vascularity, Capillary density, O2 extraction)
Metabolism (Substrate delivery, muscle mass, Oxidative capacity)
What determines oxidative capacity?
Oxidative capacity is higher in exercising muscles than in non-exercising muscles.
What does “muscle mitochondrial capacity exceeds maximal oxygen delivery in humans.” Indicate about VO2 max?
Oxidative capacity is not likely the limitation of VO2 max but O2 delivery can be.
How are VO2 max and cardiac output related?
VO2 max is correlated closely with systemic O2 delivery.
What is the limiting factor during exercise induced arterial hypoxemia?
Respiratory system
What factors can be improved to increase central circulation?
Blood volume increase
Red cell mass
How are stroke volume and VO2 max related?
high stroke volumes are correlated with High VO2 max values
What is the difference in a muscle’s capacity to perform exercise when working alone or as a part of a group of muscles? What does this indicate about the heritability of VO2 max?
Small muscle mass active means all blood required can be given to that muscle more easily. When active muscle mass is increased significantly the blood flow is limited decreasing the overall VO2 max. This indicates that maximal cardiac output can be limited by genetics.
What happens to a heart without a pericardium and how does this influence VO2 max?
Pericardectomy results in higher cardiac output and in turn higher VO2 max.
How is capillary density related to VO2 max?
Larger muscle capillary density is correlated with a higher VO2 max.
