Exercise Flashcards
Ventilatory Threshold
Disproportionate increase in minute ventilation in regards to exercise intensity
VO2max
Maximum rate of oxygen consumption during exercise; seen as a plateau on the exercise test
*Can decrease with age, gender, genetics, or lack of exercise
Central Command Mechanism
Large increase in respiratory activity at the very start of exercise; similar to response of CV system
*Consists of the PFC, insula, and anterior cingulate gyrus
Control Mechanisms for Exercise Adaptation
- Central Command Mechanism
- ANS in medulla receives input to increase sympathetic activity
- Mechanical (skeletal muscle pump and increased respiration depth)
- Metabolic (active muscles release vasodilators)
- Catecholamine release
ER at low concentrations
Binds to B-receptors in the heart; increases inotropy
ER at high concentrations
Binds to alpha and beta receptors; induces systemic vasoconstriction and increased cardiac inotropy
SV during exercise
Increases due to: Skeletal-muscle pump
Deeper respirations
Arterial vasodilation
Venous vasoconstriction (decreased compliance)
Increased inotropy of ventricles and atria
SVR during exercise
Decreases; due to vasodilation in active muscles
MAP during exercise
Increases
*This normally causes an increased in BP, however, the arterial baroreceptors will operate at a higher level to prevent this during exercise
Increase in blood flow to contracting muscles
Due to: Increased CO
Constriction of splanchnic vessels
Blood flow to skin during exercise
Increased; this allows the internal temperature to be controlled
Training effects on HR and SV
Maximal HR=no change
Maximal SV=increased
Training effects on O2 extraction
Increased due to: increased # of capillaries; decreased diffusion distance
Increased # of mitochondria
Increased # of oxidative enzymes
Increased size of plasma compartment
*Gives athletes slightly lower Hb levels
Arterial pH in exercise
Constant until dramatic drop at Ventilatory threshold
-Ventilation cannot keep up w/ developing acidosis
PaCO2 in exercise
Increases until Ventilatory threshold occurs causing increased expiration of CO2
*Occurs due to the developing metabolic acidosis
