Cardiovascular Exercise Responses (including prep lectures Flashcards
diastole
T-wave to QRS
systole
*there is overlap bc atria fill while chambers contract
QRS to T wave
End- diastolic volume
amount of blood in ventricles just prior to contraction
End-systolic volume
amount of blood left in ventricles just after contraction
isovolumeric vs. isovolumetric contraction
isovolumeric is the contraction while inlet and outlet valves are still closed, isovolumetric is the heart contraction that pushes blood out through the valves
ejection phase-
while inlet valves are closed and outlet valves are open
isovolumeric relaxation
all valves closed, pressure falls rapidly. When pressure of ventricles
parasympathetic control of the heart
vagus nerve controls SA node from rest to moderate activity. parasympathetic nerves are in atria and surround nodes
sympathetic control of the heart
chain ganglia have nerves all over the heart anatomy
VO2max equation
VO2max= Q (HR*SV) * aVO2 difference
components of SV
Preload
Afterload
Contractility
HR
- SV equation
- how does it change graphically with work
- end diastolic volume- End systolic volume
- increases curvilinearly until it reaches max at 50% aerobic capacity and my increase slightly from there
Why does resting HR increase with age
likely due to decreased parasympathetic control
- ventilation
- respiration
- air in and out
- exchange of O2 and CO2
Ventilation equation
VE=TV*f in liters/min
during mild-moderate exercise, VE is increased by _____. During vigorous exercise, _____
-increased tidal volume, increased breathing rate
Tidal volume & RR increases until, ____% of peak exercise, then ____
-70-80%, RR^
What is AT/LT/VT
lactate threshold; where blood becomes acidic and harder to clear. How well you clear it determines endurance. This is also the ventilatory break point
venous constriction (or really just decreased compliance results in what things?
- increased pressure in peripheral veins without change in resistance
- increased venous return
- increased bloof flow to heart
- increased preload (thus Frank starling mechanism)
Velocity of blood flow is _________ to the CSA of the vessel
- 2x length, ___
- 2x radius, ___
- 2x viscosity, ___
- inversely proportional
- flow decreases by 50%
- flow increases 16 fold
- flow decreases 50%
sheer stress
blood flows through vessels causing friction on the endothelial wall. Healthy individuals will release NO in response. Sclerotic vessels will experience more sheer stress (tension)
vascular tone
- extrinsic factors
- intrinsic factors
health of the vessel, degree of constriction
- neural (+) and hormonal (+)
- metabolites (-), local hormones (+/-), myogenic (+), endothelial factors (+/-)
Active hyperemia
increase in blood flow to meet the metabolic demand of activity
Reactive hyperemia
blood flow is transiently increased following a brief period of total ischemia
What is the intrinsic rate of the SA node?
~72 bpm
Why do athletes have a lower HR?
- higher SV (left ventricle thicker), thus Q
- PSM control increases
Anaerobic threshold
- rise in ___ disproportionate to ___
- indicates body can’t solely supply energy via ____ any more
- above AT, cant ________
- can _____
- decreased ___
- CO2, O2
- aerobic metabolism
- sustain prolonged workload
- increase with training
- pH
Respiratory Exchange Ratio
- equation
- ___ with exercise
- ____ indicates max effort
- ___ indicates anaerobic metabolism is present
- RER=VCO2/VO2
- increases
- > 1.09
- > 1.00
The higher your VO2max, ____________________
the lower your VO2 will be at a given submaximal workload
Q
- what is it?
- equation
- rest
- exercise
- change with workload
- amount of blood pumped from the heart per unit time
- Q= HR*SV
- rest ~5L/min
- exercise ~20 L/min
- increases linearly up to 50% due to HR and SV. After 50%, primarily due to HR
Skeletal muscle receives __% of Q distribution at rest and __% with exercise
25, 85
Maximal Q __ with conditioning. _____ at any fixed submaximal work rate
increases, remains about unchanged
SV
- normal max
- change with work rate
- 100-200ml/beat
- increases curvilinearly until reaching near max at 50% aerobic capacity
Ejection Fraction
- what is it?
- equation
- average
- proportion of blood pumped out of the left ventricle per beat
- EF=SV/EDV
- ~60% in healthy adults
Can’t really increase max HR, but ______
can still increase VO2 (via increase in SV)
Karvonen Formula
[training range % (max HR-resting HR)]+resting HR
*will calculate twice to get high and low numbers of range
HR should drop _____ bpm within first minute of stopping activity
12-18
Minute Ventilation
-VE; how much air you take in or expire per minute. Analogous to Q
Fick’s Law of Diffusion
amount of gas that moves across a sheet of tissue is proportional to the area of the sheet but inversely proportional to its thickness
dyspnea
SOA during exercise that is most often caused by inability to readjust blood PCO2 and H+ due to poor conditioning of respiratory muscles
To best clear lactate, recovery should be ____
active
A-VO2 at rest vs. exercise
5 mL/O2/100mL/dl
15
What happens to blood volume with endurance training/.
-hematocrit?
increases. Plasma volume increases a lot so hematocrit should be low
Why don’t vessels supplying active muscle contract w/ sympathetic activation during exercise?
endothelial lining releases NO to inhibit SNS and vasodilate
Size of friction in sheer stress due to ______
rate of sliding and fluid viscosity
BP
- equation
- changes with exercise
- BP= Q * TPR
- systolic increases linearly with intensity
- diastolic may decrease slightly or remain unchanged
- max BP doesn’t change
Nervous system control of Arterial BP (short and long term)
short term- CV system (pulm and cardiac stretch receptors)
long term- kidneys
Aging
all values pretty much decrease, except peripheral vascular resistance increases, and SUBMAX HR and BP increase
