Cardiovascular Adaptations to Training

Is resting heart, cardiac output or stroke volume influenced by endurance training?

Cardiac Output at rest it is the same for trained and untrained but with different variables during maximal exercise trained is almost double untrained due to increased stroke volume Heart Rate resting heart rate is affected by training it is lower in a trained than untrained training allows for quicker heart rate recovery increased parasympathetic activity decreased sympathetic activity together they lower resting heart rate

What does the Fick equation say VO2 is influenced by?

VO2= CO X a-vo2 difference it is influenced by CO and a-vo2 difference

Beyond 40-50% of VO2Max what accounts for rise in CO?

any increase in CO after 50% of VO2Max is by increased heart rate

How does blood flow through the working skeletal muscle increase during exercise? What is the Mechanism for this adaptation?

at rest 20% of CO to muscle during exercise 80-85% of CO to muscle the increased blood volume increases the venous return causing increased blood flow. The ventricles increase in filling so there is an increase also in blood ejected from the heart. The end diastolic volume stretches myocardial fibers which increases the force contracting the heart so it will contract more quickly circulating more blood in the body.

sympathetic activity

excitatory, increases heart rate and conduction through heart

Stroke Volume

increased blood volume, increased ventricular filling (relates to lowered heart rate) increased myocardial contractibility( more forceful heart beats) increased size of left ventricle

How does endurance training increase maximal a-VO2 difference?

increased capillary number (interface for gas exchange) increased mitochondrial density increased aerobic enzyme activity

Eccentric Hypertrophy

increased size of Left Ventricle cavity (volume increases by 25%) associated with aerobic training increased plasma volume-> ventricular enlargement dilated heart-> increased capacity to pump more blood higher SV

parasympathetic activity

inhibitory, decreases heart rate and conduction throughout heart

Does Endurance Training influence Maximal SV or CO?

it influences Cardiac Output. Stroke Volume increases due to decreased heart rate

Is Maximal Heart Rate influenced by Endurance Training?

no change with training

What organ maintains blood flow percentage form rest to exercise? Does the percentage of O2 extraction change between rest and exercise?

the heart maintains blood flow percentage the percentage of extraction remains the same because the heart is already extracting the max amount available

Define a-VO2 difference? What happens to this variable with increasing exercise intensity?

the volume of oxygen that can be taken up and used by the body, the difference in oxygen concentration in the arterioles compared to the venules as exercise intensity increases O2 consumption increases by increased cardiac output and increased a-VO2 difference with increased exercise intensity there is a higher ml O2 per 100 ml blood Sedentary 15ml O2 per 100ml blood Trained 17ml O2 per 100 ml blood trained have increased capillary number and increased transit time meaning increased time for gas exchange

How do most organs adapt to the reduced percentage of blood flow provided to them during exercise?

they increase extraction to adapt to decreased blood flow

Concentric Hypertrophy

thickening of heart walls, associated with resistance training walls get thicker but no increase in volume or cardiac output repetitive forceful contractions-> short term blood pressure increase-> increase resistance to blood flow to overcome blood flow resistance-> heart wall thickens to move blood against resistance

Explain Why women require a high CO at a given sub maximal O2 consumption

women require 5-10% higher CO due to 10% lower hemoglobin levels, the volume of blood in females carries less O2 so they need to pump more blood to deliver same absolute amount of O2