Transcript 4340cardio3

THE CARDIOVASCULAR
SYSTEM
Anatomy
Acute
Exercise
Chronic Exercise
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

CARDIAC OUTPUT AND TRAINING
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?

Stroke Volume

What is responsible for a higher SVmax?
LEFT VENTRICULAR HYPERTROPHY
STROKE VOLUME AND TRAINING
DIFFERENCES IN EDV, ESV, AND EF
Filling Volume
Residual Volume
Percent of Total
Volume Ejected
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

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

Stroke Volume

What type of aerobic training is most
effective in strengthening the heart and
thus increasing stroke volume?
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?

HEART RATE AND TRAINING
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
HEART RATE RECOVERY AND TRAINING
Blood Flow
What other changes occur with training
that allow for an increase in blood flow to
the muscle?
 Capillaries?
 Blood?

Capillaries
BLOOD AND PLASMA VOLUME AND
TRAINING

Blood Volume?

Red Blood
Cells?

Hematrocrit?

Viscosity?

Blood flow
distribution?
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.
w Changes in plasma volume are highly correlated. with
changes in SV and VO2max.
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

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
Cardiovascular Adaptations to Training
VO2
Q
HR
SV
a-v O2
Difference
Rest
Same
Dec
Inc
Same
Submax
Same
Dec
Inc
Same
Performance
Inc
Same
Inc
Inc
Max
Inc
Same
Inc
Inc
(same
intensity)
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.
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?

BLOOD LACTATE AND TRAINING
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?

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?
Maximal Exercise
Increase in VO2max
 Increase SV and blood volume
 Indicator of aerobic fitness level

.
CHANGE IN RACE PACE, NOT VO2MAX
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.
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.
w Pulmonary ventilation increases during
maximal effort after training.
(continued)
Respiratory Adaptations to Training
w Pulmonary diffusion increases at maximal
work rates.
w The a-vO
2 diff increases with training due
to more oxygen being extracted by tissues.
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.