Chapter 5.3 Acute responses of the cardiovascular system Flashcards
(21 cards)
what is an acute response to exercise
It is an immediate, short-term physiological response that occurs during exercise and for a short time after.
Name 6 acute cardiovascular responses to exercise
- increased heart rate.
- increased stroke volume
3.increased cardiac output - increased blood pressure
- redistribution of blood flow to working muscles
- increased arteriovenous oxygen difference (a-VO2 diff)
what is heart rate (HR)
the number of heart beats per minute
what causes heart rate to increase just before exercise starts?
Anticipatory response due to adrenaline (epinephrine)
how does heart rate increase during exercise
linearly with exercise intensity until maximum heart rate is reached.
what is stroke volume
the amount of blood ejected from the left ventricle per beat
what does stroke volume plateau
at 40-60% of maximum heart rate during exercise.
what is cardiac output (Q)
the amount of blood pumped by the heart per minute (Q=HR x SV)
what is the average cardiac output at rest and at maximal exercise?
4-6 L/min at rest, and 20-25 L/min at maximal intensity (up to 35-40 L/min in elite athletes)
during submaximal exercise, what causes the increase in cardiac output?
increases in both stroke volume and heart rate
During high intensity exercise, what mainly causes increased cardiac output?
increased heart rate (as stroke volume plateaus)
What is blood pressure?
the pressure of blood against artery walls
Blood pressure is the force of blood against artery walls as the heart pumps it through the body. It has two key measurements: systolic (pressure when the heart beats) and diastolic (pressure when the heart rests).
blood pressure=
systolic/diastolic X mmHG
What happens to blood pressure during aerobic exercise?
Systolic BP increases, Diastolic BP remains relatively unchanged.
What is systolic blood pressure?
The pressure when the heart contracts
What is diastolic blood pressure?
The pressure when the heart relaxes.
What happens to blood pressure during resistance training?
both systolic and diastolic blood pressure increase significantly.
What is redistribution of blood flow during exercise?
More blood is directed to working muscles (80-90%) and less to non-essential organs.
What is vasodilation?
Widening of blood vessels to increase blood flow to muscles.
What is vasoconstriction?
Narrowing blood vessels to reduce blood flow to less active areas.
What is arteriovenous oxygen difference (a-VO2 diff)
the difference in oxygen concentration between arterial and venous blood.
What is the typical a-VO₂ diff at rest and how does it change during exercise?
5 mL O₂/100 mL blood at rest; increases up to 15 mL/100 mL during exercise.
