THE CARDIOVASCULAR SYSTEM

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THE CARDIOVASCULAR SYSTEM

• Anatomy
• Acute Exercise
• Chronic Exercise

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Adaptations to Chronic Exercise

• Increase VO2max.
• What does a higher VO2max indicate?
• What is responsible for an increase in VO2max?
• VO2max Qmax x a-vO2 difference

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CARDIAC OUTPUT AND TRAINING
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Cardiac Output

• What is responsible for a higher maximal cardiac
  output?
• Q HRmax x SVmax
• Does HRmax increase with training?
• Does SVmax increase with training?

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Stroke Volume

• What is responsible for a higher SVmax?

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LEFT VENTRICULAR HYPERTROPHY
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STROKE VOLUME AND TRAINING
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DIFFERENCES IN EDV, ESV, AND EF
Filling Volume Residual Volume Percent
of Total Volume Ejected
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Stroke Volume

• A larger and stronger heart produces an increase
  in stroke volume at rest, submaximal exercise and
  maximal exercise
• A higher stroke volume at rest and submaximal
  exercise will allow for a lower heart rate
  without changing cardiac output

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Stroke Volume

• A higher maximal stroke volume will produce a
  higher cardiac output
• A higher cardiac output will produce a higher
  VO2max
• A higher VO2max indicates a greater ability for
  aerobic energy production

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Stroke Volume

• What type of aerobic training is most effective
  in strengthening the heart and thus increasing
  stroke volume?

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Heart Rate

• What affect will a larger SV have on resting HR?
• What affect will a larger SV have on submaximal
  exercise HR?
• What affect will a larger SV have on maximal
  exercise HR?

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HEART RATE AND TRAINING
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Heart Rate Recovery Period
w The time after exercise that it takes your
heart to return to its resting rate
w With training, heart rate returns to resting
level more quickly after exercise
w Has been used as an index of cardiorespiratory
fitness
w Conditions such as altitude or heat can affect
it
w Should not be used to compare individuals to
one another
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HEART RATE RECOVERY AND TRAINING
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Blood Flow

• What other changes occur with training that allow
  for an increase in blood flow to the muscle?
• Capillaries?
• Blood?

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Capillaries
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BLOOD AND PLASMA VOLUME AND TRAINING

• Blood Volume?

• Red Blood Cells?

• Hematrocrit?

• Viscosity?

• Blood flow distribution?

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Blood Volume and Training
w Endurance training, especially intense
training, increases blood volume.
w Blood volume increases due to an increase in
plasma volume (increases in ADH, aldosterone, and
plasma proteins cause more fluid to be retained
in the blood).
w Red blood cell volume increases, but increase
in plasma volume is higher thus, hematocrit
decreases.
w Blood viscosity decreases, thus improving
circulation and enhancing oxygen delivery.
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a-v O2 difference

• What else needs to happen beside an increase in
  blood flow and blood volume in order for VO2max
  to increase?
• Capillaries
• Myoglobin
• Mitochondria

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Cardiovascular Adaptations to Training
Cardiac Output
w Left ventricle size and wall thickness increase
w Stroke volume increases, as does Qmax and VO2max
w Resting and submaximal heart rates decrease
w Maximal heart rate stays the same or decreases
w Blood volume increases
w Increase in a-v O2 difference
w More capillaries, myoglobin and mitochondria
a-v O2 difference
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Cardiovascular Adaptations to Training
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Blood Pressure and Training
w Blood pressure changes little during submaximal
or maximal exercise.
w Resting blood pressure (both systolic and
diastolic) is lowered with endurance training in
individuals with borderline or moderate
hypertension.
w Blood pressure during lifting heavy weights can
cause increases in systolic and diastolic blood
pressure, but resting blood pressure after weight
lifting tends to not change or decrease.
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Lactate Threshold

• What affect would an increase oxygen supply to
  the muscles during exercise have on the lactate
  threshold?
• What affect would this have on aerobic
  performance?

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BLOOD LACTATE AND TRAINING
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At Rest

• At rest the heart can supply all the needed
  oxygen with a cardiac output of 5 liters per
  minute.
• If the resting stroke volume is higher due to
  aerobic training, how will the resting heart rate
  be different?
• What about parasympathetic stimulation?

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Submaximal Exercise

• Before training, running at 6 mph required a
  cardiac output of 15 liters.
• Also, before training this required a heart rate
  of 140 bpm
• Since after weeks of training stroke volume
  increases, what will happen to the heart rate
  while running at 6 mph? Why?
• What would happen to the running speed if the
  trained person now ran at a heart rate of 140
  bpm?
• If the lactate threshold used to occur at 6 mph,
  at what speed will it occur now? Why?

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Maximal Exercise

• Increase in VO2max
• Increase SV and blood volume
• Indicator of aerobic fitness level

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Aerobic Endurance and Performance
w Major defense against fatigue which limits
optimal performance.
w Should be the primary emphasis of training for
health and fitness.
w All athletes can benefit from maximizing their
endurance.
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Respiratory Adaptations to Training
w Static lung volumes remain unchanged tidal
volume, unchanged at rest and during submaximal
exercise, increases with maximal exertion.
w Respiratory rate stays steady at rest,
decreases with submaximal exercise, and can
increase dramatically with maximal exercise after
training.
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Respiratory Adaptations to Training
w Pulmonary diffusion increases at maximal work
rates.
w The respiratory system is seldom a limiter of
endurance performance.
w All the major adaptations of the respiratory
system to training are most apparent during
maximal exercise.