Exercise Flashcards
VO2 max =
max capacity for O2 consumption during exercise
VO2 max reflects what?
body’s ability to transport and use O2
Fick Principle states:
exercise capacity is dependent on body’s ability to do what?
ability to deliver blood and O2 to mm AND ability of tissue to extract O2 from blood
Fick eqn
VO2 = oxygen consumption
oxygen consumption = CO x a-v O2 difference
a = arterial
v = venous
a-v O2 difference = ratio of arterial to venous [O2] in blood
What is arterial oxygen content (CaO2)?
dissolved O2 + hemoglobin-bound O2
Working mm demand for O2 met how?
↑ blood flow
CO ↑ how in relationship to exercise intensity and O2 consumption?
CO ↑ directly w/ exercise intensity and O2 consumption
HR during exercise controlled by balance of?
parasymp (withdrawal) and
sympathetic (activation)
SV ↑ during exercise due to ↑ in what?
Preload and
Contractility
Preload ↑ SV how?
↑ venous return and filling = ↑ EDV
↑ EDV = ↑ force of contraction
Contractility ↑ SV how?
↑ strength of contraction = ↑ ejection fraction
How is blood flow to working mm ↑ during exercise? (4)
1) heart pumps more blood
2) shunting and redistribution of blood
3) metabolic vasodilation in working mm
4) ↓ total peripheral resistance
How does shunting ↑ blood flow to working mm?
more blood sent to working mm than resting mm
How does redistribution ↑ blood flow to working mm? (3)
1) during mm contraction, symp vasoconstriction opens upper valves/closes lower valves
2) muscle pumps blood centrally
3) increases venous return
How does vasodilation ↑ blood flow to working mm?
resting symp vasoconstriction overwhelmed by metabolic vasodilation (↑ Pco2, H+, K+, etc)
resulting in ↓total peripheral resistance
Blood NOT redistributed from what two organs?
1) Brain
2) Heart
Effect of moderate exercise on blood distribution to skin?
vasodilation -> cooling response
Effect of intense exercise on blood distribution to skin?
vasoconstriction -> to conserve CO
How does exercise affect O2 extraction at working mm?
1) extraction ↑ 3-fold
2) ↓ venous O2 content
3) ↑a-v O2 difference
What is Dynamic Exercise?
activities that keep joints and muscles moving
What is Static Exercise?
activity that exerts muscles at high intensities without movement of the joints
e.g. pushing against an unmovable object
What happens to BP during dynamic exercise? (3)
1) systolic BP ↑ (parallel to intensity of exercise)
2) diastolic BP ↓ from ↓ vascular resistance
3) low to mod ↑ in MAP
What happens to BP during static exercise? (5)
1) peripheral arterial system mechanically compressed
2) ↑ TPR, ↓ blood flow to mm
3) ↑ systolic pressure
4) ↑ diastolic pressure -> ↑ MAP
5) ↑ HR -> ↑ CO
Sustained static exercise impedes what?
venous return Ѧ SV
Training does what to VO2max?
increases it
↑ CO w/ training due to ↑ in what?
SV:
↑ L vent compliance = ↑ filling
↓ resting HR from training due to?
↑ vagal tone
↓ symp activity
What ↓ when you no longer train?
↓ CO and VO2max
What doesn’t ↓ when you no longer train?
HRmax
