what happens to cardiac output during exercise?
it increases
(HR and SV increases)
why does heart rate increase during exercise?
increased sympathetic adrenergic activity and decreased parasympathetic activity
what happens to stroke volume during exercise?
it increases
what factors increase stroke volume during exercise?
increased CVP
increased inotropy (contractility)
increased lusitropy (relaxation)
what is CVP?
central venous pressure
blood pressure in the superior vena cava near the right atrium
acts as an indicator of right ventricular preload and overall fluid status
what happens to mean arterial pressure (MAP) during exercise?
it increases
why does MAP increase during exercise despite vasodilation?
cardiac output increases more than systemic vascular resistance decreases
what happens to pulse pressure during exercise?
it increases
why does pulse pressure increase during exercise?
increased stroke volume increases systolic pressure more than disatolic pressure
what happens to central venous pressure (CVP) during exercise?
it increases
how does sympathetic activity affect veins during exercise?
causes venous constriction which increases venous return
what is the muscle pump effect?
contracting skeletal muscles push blood back toward the heart, increasing venous return
what is venous return?
the rate of blood flow back to the hearts right atrium, representing the volume of blood returning to the heart per minute
what is abdominothoracic pump?
breathing movements that help draw venous blood back to the heart
what happens to the systemic vascular resistance (SVR) during exercise?
it decreases overall
what is cutaneous vasodilation?
the widening of blood vessels in the skin
why does SVR decrease during exercise?
metabolic vasodilation in active muscles and the heart
what happens to skin blood vessels during exercise?
cutaneous vasodilation (due to reduced sympathetic adrenergic activity)
which areas vasoconstriction during exercise?
splanchnic
nonactive muscle
renal circulation
what is metabolic vasodilation?
the widening of arterioled and precapillary sphicters in response to increases tissue metabolic activity
why does vasoconstriction occur in nonessential organs during exercise?
increased sympathetic adrenergic activity redistributes blood to active tissues
what is adrenergic?
refers to nerve fibres, receptors and neurotransmitters involved in sympathetic nervous system
what is sympathetic nervous system?
fight or flight
responses during danger, stress or intense activity
increases HR, dilates pupils, widens airways and redirects blood flow to muscles while suppressing digestion
what is parasympathetic nervous system?
rest and digestion
system to conserve energy
reduces HR, lower BP and active digestion
