November 27, 2023 Flashcards
Review questions in beginning of lecture
how does HR, SV cardiac output(Q) compare during submaximal exercise in trained vs. untrained vs. Heart Failure(HF) individuals?
↓(lower) HR in T
↑(higher) SV is in T
Q is the same in T,UT, and HF people
page 152
what is a major adaptation of endurance training during submaximal exercise
Better myocardial O2 (ATP) supply
Less ATP demand, meaning reduced myocardial O2 use (VO2)
page 152
During maximal exercise how does training increase VO2max in regards to Q
During maximal exercise, training increases VO2 max by increasing Qmax
this is because the higher SV means that there is greater HR reserve to call upon at maximal exercise
page 152
what is the only way to increase Q in a patient with heart failure
In a patient with heart failure, SV cannot increase, so HR is the only way to increase Q →
large increase in cardiac work at a low workload
page 152
how are Cardiac work and ATP demand of the heart are estimated in a clinical setting
by the “rate pressure product”
Cardiac work and ATP demand of the heart are estimated in a clinical setting by the
“rate pressure product”
page 152
what are the Effects of Chronic Exercise Training on Left Ventricular Dimensions for ENDURANCE ATHLETES
Modest thickening of LV
LV dilation (bigger chamber, lengthening cells)
“Volume” overload → eccentric hypertrophy
page 153
what are the Effects of Chronic Exercise Training on Left Ventricular Dimensions for STRENGTH ATHLETES
Thickening of LV walls
no LV dilation (no change in chamber, thicker cells)
“Pressure” overload → concentric hypertrophy
page 153
“Volume overload → eccentric hypertrophy” is an adaptation in which type of athlete
ENDURANCE ATHLETES
page 153
“Pressure overload → concentric hypertrophy” is an adaptation in which type of athlete
STRENGTH ATHLETES
page 153
what are the Effects of Chronic Exercise Training on Left Ventricular Dimensions for a COMBO ATHLETE (BOTH STRENGTH AND ENDURANCE)
Thickest LV walls
LV dilation
Combination of “pressure” and “volume” overload
page 153
“Combination of pressure” and volume overload” is an adaptation in which type of athlete
COMBO ATHLETE (BOTH STRENGTH AND ENDURANCE)
page 153
what can Chronic pressure overload (hypertension) lead to
initial concentric hypertrophy leads to:
dilated cardiomyopathy (dilation (enlargement) of the heart chambers)
heart failure
LV wall thinning
page 153
what is the result of Chronic pressure overload (hypertension)
EF is low; this is pathological hypertrophy
page 153
what is an similarity between athlete’s heart and failing heart
Both athlete’s heart and failing heart have an increase in heart mass
page 153
what are differences between Athletes heart and Failing Heart
Athlete:
normal/increasesd cardiac function
reversible
Failing Heart:
↓ cardiac function
irreversible
cell death/fibrosis
increased mortality
page 153
how does Exercise Training Protects the Heart:
Hint: 3 reasons
Improved blood flow distribution to cells (training-induced cardiac angiogenesis)
Increased synthesis of “stress” proteins, which refold damaged proteins brought about by ischemia
Training induced increases in the heart’s antioxidant capacity; the ability to remove free radical molecules or reactive O2 species, which damage protein lipids and DNA
Fick equation:
VO2 = Q x (a-v)O2
O2 going into the muscle, and O2 coming out of the muscle (difference between this)
ex:
20 is the arterial O2 content vols % (going in)
15 is the venous O2 content vols % (untrained) (going out)
Difference of 5
page 155 look at equation
how Training lead to an improvement in O2 extraction in regards to the fick equation
increased difference in (a-v)O2 because:
increased mitochondria content
increased capillary:fibre ratio (angiogenesis)
VO2 max goes up with training due to …..
an increase in cardiac output (Q) and an increase in (a-v)O2
what is angiogenesis
Angiogenesis is the physiological process through which new blood vessels are formed from pre-existing blood vessels.
Newly formed capillaries improve….
flow distribution to individual fibres (increase
capillary:fibre ratio)
↑ capillary:fibre ratio →
Shorter diffusion distance
How does exercise-induced angiogenesis occur
Exercise →
an increased expression of vascular endothelial growth factor (VEGF) in muscle fibres →
Secretion into ECF →
Binds to VEGF-R on endothelial cells (receptor) →
Proliferation and migration of EC to form new capillaries
what is is required for exercise training induced skeletal muscle angiogenesis
Muscle cell-derived VEGF
Without VEG-F….
few capillaries around fibres
nothing happens with exercise (could not improve in absence of VEG-F)
page 157
