Transcript L10- Exercise respir..

Effects of exercise on the
respiratory system.
Dr Abdulrahman Alhowikan
Collage of medicine
Physiology Dep.
Aims
By the end of this lecture the students should
be able to:
 Understand the difference between dynamic and
isometric exercise.
 Describe the effects of moderate and severe
exercise on oxygen consumption (Vo2 Max) , and
ventilation volumes.
 Describe the effects of exercise on arterial PO2,
PCO2 and H+ ions.
 Define the diffusing capacity of the respiratory
membrane, and its typical values at rest, and
explain its changes in exercise.
 Explain causes of hyperventilation in exercise.
the difference between dynamic
and isometric exercise
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isometric exercise
Muscle contraction is said to be isometric (static)
when the muscle does not shorten during contraction
static strength training, involve muscular actions in
which the length of the muscle does not change and
there is no visible movement at the joint eg Pushing
wall
strengthening the muscles without stress on the joint
eg in rehabilitation
drives up blood pressure and Valsalva-Maneuver
static strength required to stabilize the upper and
lower body
the difference between dynamic
and isometric exercise cont…
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dynamic exercise
dynamic exercises increase strength
throughout the full rang of motion
Blood circulation, strength, and endurance
are improved by these continuous
movements
Eg. swimming, walking
effects of moderate and severe exercise
on oxygen consumption, and ventilation
volumes.
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Normal oxygen consumption (Vo2 Max)
for a young man at rest is about 250
ml/min.
However, under maximal conditions!
Untrained average male 3600ml/min
Athletically trained average male 4000ml/min
Male marathon runner 5100ml/min
Compare Maximal oxygen consumption with other
population
(40-50) y
36.1
(30-39) y
(20-29) y
Reference
40.4
46.3
German
medical staff
42.3
47.4
51.7
Canadian
Sedentary
23.9
28.88
31.55
Saudi
sedentary
Peak cardiopulmonary function in healthy Saudi
males (mean ± SD). (103)
Age (years)
(40-50)
(30-39)
0.27 ±1.93
3.6 ±23.9
8 ± 172
± 82.3
14.2
(20-29)
0.29 ± 2.23
0.32± 2.22 VO2 peak (L. min-1)
5.5 ±28.9
**
*
5.9±31.6
**
8±178
**
15±90.2
Variables
8 ± 183
VO2 peak (ml. kg.-1
min-1)
HR peak (bpm)
*
14.6±89.6
VE peak
(L. min-1)
effects of exercise intensity on
oxygen consumption
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during the first 60-120 seconds of effort
there is an increase in pulmonary blood
flow (phase I or the cardio-dynamic
phase)
before a rapid increase in oxygen
consumption related to muscle extraction
of O2 (phase II or the oxygen uptake
kinetic phase)
before reaching steady-state (phase III) if
the work load does not result in the
accumulation of blood lactate.
Relation between oxygen consumption and total
pulmonary ventilation at different levels of
exercise.
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There is a linear
relation between both
oxygen consumption
(Vo2 Max) and total
pulmonary ventilation
increase about 20-fold
between the resting
state and maximal
intensity of exercise in
the well-trained
athlete.
Causes of hyperventilation in exercise.
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During maximal effort:
Pulmonary ventilation at maximal exercise
100-110L/min
 Maximal breathing capacity 150-170L/min
 maximal breathing capacity is about 50 %
greater than the actual pulmonary ventilation
during maximal exercise. to giving athletes
extra ventilation E.g
(1) exercise at high altitudes,
(2) exercise under very hot conditions, and
(3) abnormalities in the respiratory system.
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Causes of hyperventilation in exercise
cont...
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Respiration is stimulated mainly by
neurogenic mechanisms during exercise
Stimulation results from direct
stimulation of the respiratory center by
the same nervous signals that are
transmitted from the brain to the muscles
An additional part is believed to result
from sensory signals transmitted into the
respiratory center from the contracting
muscles and moving joints
Effects of exercise on arterial PO2,
PCO2 and H+ ions.
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Many studies have since reported that the lactat
threshold (LT) is strongly correlated with ventilatory
anaerobic threshold (VAT)The term VAT actually
refers to the onset of exercise induced
hyperventilation during effort. This increase in is a
homeostatic response to deal with the consequences
of the excess lactate production which can dissociate
to release H+ ions from lactic acid into the blood
stream. The H+ ions are buffered by bicarbonate
and release CO2 .This buffering of lactic acid results
in extra CO2 production over that produced by
aerobic metabolism and increases the arterial CO2
partial pressure (PaCO2). The increase in PaCO2
stimulates excess ventilation that follows on from the
lactate threshold.
the lactat threshold (LT) is strongly
correlated with ventilatory
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http://www.youtube.com/watch?v=
VBJ97oeyor0
Oxygen-Diffusing Capacity of
Athletes
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The oxygen-diffusing capacity is a measure
of the rate at which oxygen can diffuse from
the pulmonary alveoli into the blood
It is expressed in terms of milliliters of
oxygen that will diffuse each minute for
each millimeter of mercury
difference between alveolar partial pressure
of oxygen and pulmonary blood oxygen
pressure.
Oxygen-Diffusing Capacity of
Athletes cont…
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differences between diffusing
capacity at resting and the state of
maximal exercise make blood flow
through many of the pulmonary
capillaries and providing greater
surface area through which oxygen
can diffuse into the pulmonary
capillary of blood.
Oxygen-Diffusing Capacity of
Athletes cont…
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The saturation of red blood cells in the pulmonary
capillary influenced by cardiac output. And that, might
reducing the time for saturation of red blood cells with
oxygen In addition, the saturation of blood artery
(%SaO2) remain constant 95% at rest and during
maximal effort, due to proportional correlation between
diffusion of red blood cells and increase exercise
intensities.
However, the impact of reduce pulmonary diffusion in
oxygen uptake can be noticed in the reduction of
exercise capacity by exercising at high altitudes level
(3000-5000 m) in which the O2 concentration at
atmosphere reduced less than 20.9% in addition, that
can be noticed in patients with COPD such as exercise
induce by asthma.
Reference book
Guyton & Hall: Textbook of Medical Physiology 12E
Thank you