Exercise Flashcards
What is Acute?
Single, isolated session that elicits transient physiological response
What is Chronic?
Repetition of single bouts
produce permanent physiological adaptations
Exercise training response
What are general responses to acute exercise?
Increased metabolism due to increased muscle contraction
Cardiovascular system increases to meet metabolic demand
Adjusting Q, blood flow and pressure
Acute
What is Resting Heart Rate?
Average HR = 70 bpm highly variable (40-100bpm) Affected by -environment and stress Decreases with age and increase cardiovascular fitness
Acute
What is the HR response to exercise?
HR increases at exercise onset
-Levels off during submax
-increases during graded exercise
Plateau at HR max
Acute
What is max HR?
Highest HR is acheived during max 215-220 bpm Declines with age Sympathetic increases Parasympathetic decreases
Formula HR SV Q MABP
220-age
EDV-ESV
HR x SV
Q x TPR
Acute
Stroke Volume at rest
Blood pumped by one ventricle in a single contraction
Average is 70ml/beat
25% lower in women
Acute
Stroke Response to exercise
SV increases at exercise onset up to 40-60% max intensity
May increase up until max (depends on body position)
Major determinant of max cardiovascular work capacity
Three Mechanisms responsible for increasing SV
1) Frank-Starling Mechanism
2) Increased contractility due to sympathetic stimulation
3) Reduced TPR
1) Frank - Starling Mechanism
Increased venous return = increase blood prior to contraction
Increased EDV stretches (Preload)
Greater stretch = greater force
Increased SV
2) Increased contractility due to sympathetic stim
Independent of changes in EDV
Greater stretch - optimal length - greater contractility
3) Reduced TPR (After load)
Vasodilation in working muscles
Acute
What is Cardiac Output?
Volume of blood pumped/ventricle during a given period of time
Average 5ml/min
Indicator of cardiovascular systems capacity to meet exercise demands
Acute
Cardiac output during exercise
Increase during exercise with increase intensity
Amount of increase depend on trained state
Sedentary = 20L/min
Trained = 40L/min
When intensity exceed 40-60% max, Q increase is due to increased HR
Acute
Blood Flow
At rest muscles receive 20-25% of Q
During exercise muscles receive up to 90% of Q
Acute
Blood Flow during exercise
Increase tissue metabolism
Increase release of metabolic vasodilators into ECF
Arterioles dilate
Decrease resistance = increase blood flow
O2 and nutrients supply to tissue increases as long as metabolism increases
What is blood flow determined by?
Ateriole diameter is controlled by what?
Vessels resistance to flow
Tonic release of nor-epinephrine
(increased signal rate, blood vessels constrict, decrease signal = vessels dilate)
Acute
Blood Pressure during exercise
Mean arterial BP rises slightly despite decrease resistance
Depends on type of exercise
Acute
What are theories for increase in MAP without activating baroreceptors reflex?
Receptors threshold is reset to higher pressure
Central inhibition of afferent signal
Chemoreceptors sensitive to metabolites override barorecpetor reflex
Chronic cardiovascular adaptations to training
Aerobic exercise training
Improve endurance
Important measure to assess endurance capacity is VO2 max
What is VO2 max and what systems are involved?
The max intake, transportation and utilization of oxygen.
Integration of cardiovascular/respiratory and neuromuscular system
What changes occur with increased VO2 max?
HR SV Q Heart size BP Blood flow Blood volume
Chronic
Hear rate
Decrease with endurance training
Highly trained have bradycardia
Increase in parasympathetic activity
Decrease in SA node firing
Chronic
Submax HR
Decreases with training
Heart does not beat as fast for same amount of work
Chronic
Maximal HR
Remains unchanged or slightly decreased
Chronic
Stoke volume
Increased at rest, submax and max
Chronic
What causes the increase in SV
Greater EDV (increased volume and filling time) Increase in ventricle size
Chronic
Cardiac Output
Remains unchanged at rest and during submax exercise
Increases at max due to increased SV (HR max remains changed)
More filling time
Larger ventricles
More blood volume
More time between beats
Greater stretch/ preload
Greater stretch= greater force
Over all the heart is better at getting blood from the heart to the body
What happen to heart size?
Cardiac hypertrophy is a result from training
-Increase wall thickness
-Increase in cavity size
Depends on overload stimulus
What is pressure overload?
pressure due to afterload as a result of strength training
Heart contracts harder against resistance
Concentric hypertrophy
What is volume overload?
Volume due to high preload and amount of blood passing through
Increased stretch = increased size
Eccentric hypertrophy
What cavity of the heart changes the most?
Left ventricle because of increased filling. Mostly cavity size increase in endurance but there is some wall size increase
Chronic
Blood Pressure
Both systolic and diastolic decrease at rest
Most pronounced in people with hypertension
Reduces sympathetic hormones
May decrease during submax
Chronic
Blood Flow
Increases with training
- increased max Q
- increase blood volume
- more effective blood distribution
- increased capillarization
Chronic
Blood Volume
Increase with training due to increased plasma RBC increase (decrease hematocrit though b/c plasma increases more)
What does increased blood volume do?
Enhances thermoregulation and circulation and facilitates in O2 delivery
contributes to eccentric hypertophy and increases SV
