Cardiovascular System and Exercise Flashcards
What is the cardiovascular system involved in?
- Transport CO2 and O2
- Supply nutrients
- Waste removal
- Regulate blood flow
- Thermoregulation
BP =
Q x TPR
What is blood pressure?
The force of the blood during the ejection from the left ventricle
Systolic (stretch of the arteries)
Diastolic (relaxation of the arteries)
What is total peripheral resistance?
The resistance to blood flow created by the vascular system
What are factors that increase TPR?
Decreased artery radius
Increase viscosity of the blood
What is the pulse rate?
The force of the blood during ejection from the left which creates a wave of pressure through the arterial system and can be measured as a pulse.
Accurate measurement: HR = pulse rate
What happens to systolic blood pressure during rhythmic exercise?
Increase until max exercise due to increase in Q
What happens to diastolic blood pressure during rhythmic?
Stays the same or slightly decreases due to reduced TPR because of vasodilation
At max exercise diastolic pressure may increase slightly due to higher Q and muscle tension
What happens to blood pressure above 50% max voluntary contraction?
Systolic increases due to increased TPR
Diastolic may increase with prolonged intense contraction
What is the Valsalva Maneuver?
Attempting to exhale with the nostrils and mouth closed
Increases BP
Creates a stable frame for muscle contractions
What is the difference between upper and lower body exercise strength exercise at 50% MVC?
Higher BP in arms because of smaller muscle mass and vasculature
What is hypertension?
High blood pressure 140/90
Due to increase TPR associated with atherosclerosis, diet, obesity, diabetes, stress, inactivity
What is hypotension?
Low blood pressure 90/60
caused by low blood volume, venous pooling, certain medication, endocrine response
The heart is…
Very aerobic muscle
- Highly vasculature
- Highly oxygen extraction (70-80% at rest)
How does the heart have high aerobic metabolism?
Lots of mitochondria
Highest fat metabolism
High LDH (h) favouring lactate metabolism
What is rate pressure product?
Estimation of myocardial work
RPP = BPsys x HR
Beneficial if reduced during exercise
What is the control of the heart?
1) Intrinsic pacemaker activity
2) CVC in medulla oblongata coordinates heart function
3) Extrinsic contol
- PNS -> acetylcholine -> decrease HR
- adrenal glands -> epinephrine -> increase HR
4 a) Mechano and chemoreceptors
b) Baro-receptor responds to stretch (inhibitory)
What is the intrinsic control?
Sino Atrial Nodes
What is the extrinsic control?
Medulla oblongata
-Parasympathetic (slows the HR)
-Sympathetic (increases HR)
Chemorecptors and mechanoreceptors
What are the electrical events of the heart?
Effects: the depolarization and repolarization of the atrial and ventricle
Result: coordinated contraction of the heart musculature to allow filling and emptying of blood
What can be assessed using ultra sound?
The structure of the heart, coupled with dopler blood flow can also be assessed
What directs blood flow?
Vasodilation/contsriction
How is vasodilation accomplished?
SNS: Increase acetylcholine from the cholinergic SN = Vasocnstriction to gut
Hormonal: (nor)epinephrine released from adrenal gland
Local auto-regulatory factors: associated with a working muscle trigger vasodilation
-Factors: increase temp, decrease O2
How is vasoconstriction accomplished?
These factors do not affect the vessels of the heart or muscle
Sympathetic nervous system: increase norepinephrine release from nerve ending
Hormonal response: (nor)epinephrine from adrenal medulla
What is cardiac output?
Volume of blood pumped by the ventricle/min
Q=HR x SV
Rest= 5L/min
How is vasodilation accomplished?
SNS: Increase acetylcholine from the cholinergic SN = Vasoconstriction to gut
Hormonal: (nor)epinephrine released from adrenal gland
Local auto-regulatory factors: associated with a working muscle trigger vasodilation
-Factors: increase temp, decrease O2
What is SV?
the amount of blood ejected by the ventricle per beat and depends on:
- Pre-load: blood returning to the atria
- Size of ventricle
- After load: amount force needed to great against back pressure on the heart (TPR)
What is the Frank-Starling law?
Increase pre-load Increase filling of ventricle Stretching the heart muscle Optimal fiber length Increase force of contraction Increase SV
What happens to stroke volume during exercise?
Increases up to 40-60% of VO2max
Why does it SV plateau?
Preload: decrease in preload time = faster HR with less filling time
Contractility: possible cardiac fatigue
Afterload: increase in afterload pressure
Size of ventricle: unlikely to change during exercise
Can we train SV to contribute to increase?
Enhanced pre-load: improved venous return producing an increase in EDV and contractility in elite endurance
No reduction in contractility (cardiac fatigue reduced)
What happens during submaximal aerobic exercise?
HR increase to steady state SV increases but maxes at 50-60% Increase in SBP and no change in DBP Increase in pre-load due to increase blood flow Untrained =100-120ml/bt Trained=160-180ml/bt Elite= 200ml/bt
What happens during max exercise?
Q, HR, SV are all at max SBP increase TPR is at lowest Blood flow increase Preload increase afterload increase Hemoglobin saturation decrease
What are some general training adaptation at rest?
Cardiac hypertrophy (cavity size or wall thickness) Decrease resting HR Increase SV Increase total blood volume Increase capillerization Increase oxidative capacity Decrease BP
What are training changes at submaximal exercise?
Increase SV at any given PO decrease HR slight decrease in Q
Increase a-vO2 diff
Decrease SBP
No change or slight decrease in blood flow
-Increase O2 extraction
-Increase mechanical and metabolic efficiency
-Improvements in thermoregulation
What are training changes at max exercise?
Increase Q due to increase SV
Increase max blood flow due to increase Q and decrease TPR
Increase in a-vO2diff (increase O2 extraction)
SBP same or increase
HR same or slightly lower
Increase VO2 max
What is blood doping?
Increase hematocrit Increase hemaglobin content Increase blood volume Increase O2 carrying capacity and delivery of blood Increase VO2
What is the modern technique of blood doping?
Erythropoietin (EPO) increased unnaturally
increases total amount of RBC
Increase in hemoglobin concentration
What are EPO complications?
Concentration hematocrit increase likely hood stroke, heart attack
Liver dysfunction
