Acute and Chronic Exercise Response (9/30b) [Examination/Intervention]

Question 1

HR increases due to

Answer 1

Initial (<100 bpm): parasympathetic withdrawal

Later: increased 𝛽-1 receptor activation by sympathetic stimulation and circulating catecholamines

Question 2

SV affected by Preload, Afterload, Contractility

Answer 2

Preload - affected by venous return (muscle pump)

Afterload

Contractility - affected by sympathetic stimulation & circulating catecholamines

Question 3

CO increases due to

Answer 3

Both HR and SV

SV contributes up to 45% of VO2 max

Further increase due solely to HR

CO = SV * HR

Question 4

A-v O2 difference - Increased VO2 due to increases in

Answer 4

CO

Oxygen extraction by muscle

• Due to increased oxygen consumption in active muscle, increased aerobic metabolism
• Redistribution of blood to working muscle

VO2 = CO * a-vO2 difference

Question 5

Mean arterial pressure (MAP)

Answer 5

MAP = CO * TPR
MAP = P diastolic + ⅓ pulse pressure

Pulse pressure = P systolic - P diastolic

On graph, Ps is the hill, Pd is the valley

Directly proportional to SV

• Decreased SV due to ischemia → decreased PP
• Increased SV during exercise → increased PP

Inversely proportional to vessel compliance
-Arterial stiffening with aging and arteriosclerosis → increased PP

Question 6

Systolic Blood Pressure (SBP)

Answer 6

affected by

Stroke volume, arterial compliance, and diastolic pressure

Question 7

Diastolic Blood Pressure (DBP)

Answer 7

primarily related to
CO, primarily HR
Total peripheral resistance (TPR)