The (AV) node, limits the number of impulses that can pass through it in a given time period, preventing the ventricles from being driven at excessive rates. This delaying is under the control of the autonomic nervous system and hormones. At rest, under the influence of "decelerator" nerves (parasympathetic, or "vagal" nerves), inhibitory effects dominate. During exercise, "accelerator nerves" (sympathetic or adrenergic nerves) are activated, which facilitates AV node signal transmission necessary for rapid heart rates.
How would you as a sports and exercise specialist inform your public of factors to improve performance related to your knowledge of the cardio-vascular and respiratory systems?
What and how would be entirely contextual, ranging from a personal one-to-one chat about general principles involved in training, figure 21, through to detailed measures of lactate threshold, ventilation break-point and VO2max as per the results in appendix 1, in order to allow the calculation of a heart rate at 60-80% of the threshold to improve aerobic endurance by training at that level.
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