Lecture 30: Circulatory Adaptations to Exercise Training Flashcards
What is the equation for VO2 max?
VO2max = CO * AVO2 difference
What is a standard cardiac output value for an endurance athlete?
3.9 L.min
What is a standard A-VO2 difference value for an endurance athlete?
160 ml.L
What are the peripheral adaptations to aerobic training?
Increased flow to non-exercising muscles Increased muscle blood flow Greater haemoglobin affinity Increased vascular conductance Increased capillary density Oxygen diffusion Oxygen extraction
What is the equation for MAP?
MAP = CO * TPR
What happens to TPR when cardiac output increases?
It falls to accomodate for increased cardiac output
What is a conduit artery?
An elastic artery
What effect does exercise training have on conduit arteries?
It causes them to increase in distensibility (diameter)
How did conduit artery diameter differ between dominant and non-dominant limbs?
Non-dominant limb had greater distensibility at any given blood pressure
How did conduit artery diameter differ between trained and non-trained athletes?
Distensibility at higher blood pressures
What is conductance?
The ability of a vessel to vasodilate
What effect does training have on resistance arteries?
Increased conductance
What is a resistance artery?
Found in the microcirculation
Provides a lot of resistance to flow
What is the overall effect of training on conduit and resistance arteries?
Expansion of conduit arteries
Increased number of resistance arteries
Increased distensibility of conduit arteries
Increased conductibility of resistance arteries
What two ways can we stimulate vasodilation in order to measure conductance?
Acetylcholine injection
Cuff pressure = metabolite build up
What did the injection of acetylcholine show about young and old people’s conductance?
Young people have greater conductance
Old people have greater conductance after an aerobic training program
What is angiogenesis?
Growth of new blood vessels
What are the functional advantages of increased capillary supply?
Increased transit time (more complex nature of capillaries)
Lower diffusion distance
What effect did exercise have on capillary tortuosity and density?
Increased both
What effect did aerobic training have on blood flow and A-VO2 difference during sub-maximal and maximal exercise?
Sub-max: After training there was lower blood flow due to increased A-VO2
Max: After training both blood flow and A-VO2 difference increased
What are the peripheral metabolic changes that cause increased O2 consumption, due to exercise?
Increased mitochondria
Increased oxidative enzymes
What are the peripheral vascular adaptations to exercise?
Increased artery diameter
Increased artery conductance
Increased vasodilatory regulation of vascular tone
Increased number of arteries
Increased number of capillaries
Increased transit time
Decreased diffusion distance
What is the effect of regular aerobic training on oxygen extraction?
Increased A-VO2 difference
What effect does aerobic training have on the coronary vascalurture?
Increased capillarisation (due to cardiac hypertrophy)
Increased coronary artery diameter
Increased collateral blood flow
Discuss blood flow to the splanchnic region after aerobic training.
It increases
This means there is potential for more blood flow to muscles due to greater vasoconstriction
Discuss the effect of endurance training on blood flow to the cutaneous system with increasing heat stress.
No change in temperature threshold
Increased blood flow to the skin after threshold is met
This causes better heat loss
What are the inducers of vascular remodelling?
Metabolic:
Inducing hypoxia during training causes a long-term increase in blood flow
Hypoxia causes increased VEGF secretion
Mechanical:
Increased blood flow - Increased sheer stress - Increased NO production - NO production stimulates growth - Current level of shear stress becomes normalised - Increased potential for more NO production
Growth Hormones:
VEGF stimulate growth of vascular tissue that increases ability to vasodilate
