CV changes in exercise Flashcards
What are the 4 mechanisms of controlled response to increased physical activity?
Local
Neural
Hormonal
Mechanical
What are the local responses to exercise?
Increased metabolites in cardiac muscle and skeletal muscle increase blood flow
Decreased blood flow to splanchnic and renal circulations
Vasodilation in skin to release heat
Increased CO2, H+, and 2,3-DPG favors unloading O2
What will shift the hemoglobin dissociation curve to the right?
Increased CO2
Increased H+ (decreased pH)
Increased 2,3-DPG
What does is mean if the hemoglobin dissociation curve is shifted to the right?
Favors oxygen unloading and increased oxygen extraction by tissues
What is the neural response to exercise?
Increased SyNS
Decreased PsNS
What is the response of circulation to increased SyNS during exercise?
Increased HR and contractility –> increased SV
Vasodilation of vessels supplying cardiac muscle and skeletal muscle
Venoconstriction of capacitance vessels –> increases VR
Vasoconstriction of renal and splanchnic vessels
What is the hormonal response to exercise?
Increased epinephrine –> vasodilation in muscles and renal vasoconstriction
What is the mechanical response to exercise?
Skeletal muscle pump and thoracic pump increase VR
Sustained muscle contraction impedes flow –> significant increase in HR, SBP, DBP, and MAP
What are the changes in SBP and DBP in moderate isotonic exercise?
Increase SBP
DBP unchanged
What are the changes in SBP and DBP in severe isotonic exercise?
Significant increase in SBP
Decreased DBP
What are the changes in SBP and DBP in isometric exercise?
Both increase
What occurs during rhythmic exercise?
Blood vessels dilate in active muscles
Muscles pump the blood to circulate faster
Increased blood flow increases SBP initially and then it will level off
DBP does not change significantly
Similar response in conditioned and unconditioned individuals
What occurs during resistance exercise?
Strained muscle activity compresses peripheral arteries –> significant resistance to blood flow and both SBP and DBP increase
Dangerous in HTN and heart disease pts
What are the equations for estimated HRmax?
HRmax = 220 - age in years
HRmax = 208 - (0.7 x age in years)
What is the steady-state HR?
Point of plateau, the optimal HR for meeting circulatory demands at a submaximal intensity