Exercise & circulation physiology slides.ppt

circulation physiology

1. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 11
Circulatory Changes Circulatory Changes
During ExerciseDuring Exercise

2. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 22
Circulatory Changes During Circulatory Changes During
ExerciseExercise
During exercise there During exercise there
is is
–Increase demand for Increase demand for
energy energy
–To meet the increased To meet the increased
metabolic demandsmetabolic demands
Demands is met by Demands is met by
adjustment of adjustment of
–Cardio respiratory Cardio respiratory
systemsystem

3. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 33
Muscle Blood FlowMuscle Blood Flow
At rest muscle blood At rest muscle blood
flow flow
–3 to 4 ml/ min/ 100 gm 3 to 4 ml/ min/ 100 gm
of muscleof muscle
During exerciseDuring exercise
–50 to 80 ml /min /100 50 to 80 ml /min /100
gm of musclegm of muscle
Intermittent flowIntermittent flow
–Decreases during Decreases during
contraction phasecontraction phase
–Increase between Increase between
contractionscontractions
40
20
0
0 10 16 18
B
l
o
o
d

f
l
o
w
Minutes
Rhythmic exercise

4. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 44
Circulatory Changes During Circulatory Changes During
ExerciseExercise
Major effects Major effects
occur during occur during
exerciseexercise
–Facilitate adequate Facilitate adequate
supply of blood supply of blood
required by required by
working muscle working muscle
include the include the
following..following..

5. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 55
Circulatory Changes During Circulatory Changes During
ExerciseExercise
Local mechanismsLocal mechanisms
Also during Also during
exercise there is exercise there is
increaseincrease
–Sympathetic Sympathetic
dischargedischarge
–Arterial pressureArterial pressure
–Cardiac outputCardiac output

6. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 66
Local MechanismsLocal Mechanisms
Maintain high Maintain high
blood flow in blood flow in
exercising exercising
musclesmuscles
 Tissue POTissue PO
22
 Tissue PTissue P
CO2CO2
 Local Local
temperaturetemperature
 Metabolites Metabolites

7. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 77
Local MechanismsLocal Mechanisms
Dilatation of Dilatation of
–ArteriolesArterioles
–Pre-capillary Pre-capillary
sphincterssphincters
Cause Cause
–10 to 100 fold 10 to 100 fold
increase in increase in
number of open number of open
capillariescapillaries

8. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 88
Local MechanismsLocal Mechanisms
Oxygen consumption Oxygen consumption
of skeletal musclesof skeletal muscles
 100 fold during 100 fold during
exerciseexercise
This is met byThis is met by
 COCO
Diffusion capacity of Diffusion capacity of
lunglung
–Opening of capillariesOpening of capillaries

9. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 99
OO
22-Hb Dissociation Curve-Hb Dissociation Curve
During exerciseDuring exercise
The curve shift The curve shift
to rightto right
 PHPH
 TempTemp
 2:3 DPG2:3 DPG
100
80
60
40
20
20 40 60 80 100
H
b

s
a
t
u
r
a
t
i
o
n

(
%
)
P
O2
(mm Hg)
50
27
P
50
pH 7.2
pH 7.4

10. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 1010
Local mechanism maintains a
high blood flow in exercising
muscles
Dilation of the arterioles and
precapillary sphincters cause
a 10-100-fold increase in the
number of open capillaries.
The capillary pressure
increases exceeding the
oncotic pressure throughout
the length of the capillaries.
Lymph flow is also increased
limiting the accumulation of
tissue fluid
Distribution of blood
flow at rest and during
heavy exercise
Oxygen
consumption of
skeletal muscle
increase 100-fold
during exercise
From Hansen Taher Sherief
Physiology book CD

11. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 1111
Sympathetic DischargeSympathetic Discharge
Command signals to Command signals to
the musclethe muscle
–Relayed to vasomotor Relayed to vasomotor
centrecentre
 Sympathetic Sympathetic
dischargesdischarges
 parasympathetic parasympathetic
activity to the heartactivity to the heart
This causes increase inThis causes increase in
–HRHR
–Contractility of Contractility of
myocardiummyocardium

12. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 1212
Sympathetic DischargeSympathetic Discharge
Cause constriction of Cause constriction of
most of arterioles most of arterioles
exceptexcept
–In active muscles In active muscles
Vasodilatation Vasodilatation
–Effect of local Effect of local
metabolitesmetabolites
Blood is shunted to Blood is shunted to
working musclesworking muscles
Coronary and cerebral Coronary and cerebral
vesselsvessels
–Spared of the Spared of the
vasoconstrictionvasoconstriction

13. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 1313
Sympathetic DischargeSympathetic Discharge
Constriction of Constriction of
capacitance capacitance
vessels leads tovessels leads to
 Mean systemic Mean systemic
filling pressurefilling pressure
 Venous returnVenous return
 Cardiac outputCardiac output

14. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 1414
Venoconstriction
 venous capacity
and  venous
return
Command signals to
muscles relayed to
VMC
Symp discharge
 parasymp
 HR, Contractility
From Hansen Taher Sherief
Physiology book CD

15. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 1515
Arterial PressureArterial Pressure
Arterial pressure Arterial pressure
increases during increases during
exercise due toexercise due to
–Vasoconstriction of Vasoconstriction of
arteries & arterioles arteries & arterioles
–Increased pumping Increased pumping
activity of myocardiumactivity of myocardium
–Increase mean Increase mean
systemic filling systemic filling
pressurepressure

16. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 1616
Arterial PressureArterial Pressure
All the above will All the above will
tend to increase BPtend to increase BP
–(BP = CO x TPR)(BP = CO x TPR)
The extent of the The extent of the
rise in BP rise in BP
–Depend on the type Depend on the type
of exercise of exercise
performedperformed

17. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 1717
Arterial PressureArterial Pressure
When person perform When person perform
exercise under tense exercise under tense
conditionsconditions
–Few areas of Few areas of
vasodilatationvasodilatation
–Vasoconstriction occurs Vasoconstriction occurs
in most tissuein most tissue
–TPR increases much TPR increases much
moremore
MAP rises significantly ( MAP rises significantly (
= 170 mm Hg)= 170 mm Hg)

18. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 1818
Arterial PressureArterial Pressure
When a person When a person
performs whole body performs whole body
exercise exercise
–Running, swimmingRunning, swimming
Rise in MAP Rise in MAP
–Not profoundNot profound
–Large muscle mass Large muscle mass
activeactive
VasodilatationVasodilatation
Lower TPRLower TPR

19. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 1919
Cardiac OutputCardiac Output
Systemic blood flow Systemic blood flow
–Increases with increase Increases with increase
in intensity of exercisein intensity of exercise
CO increases rapidly CO increases rapidly
initially then graduallyinitially then gradually
–Until blood flow meets Until blood flow meets
metabolic demand for metabolic demand for
the exercisethe exercise

20. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 2020
Cardiac OutputCardiac Output
In sedentary In sedentary
peoplepeople
–CO can increase CO can increase
four fold (from 5 to four fold (from 5 to
20 L/ min)20 L/ min)
Mainly by increase Mainly by increase
in bothin both
–HR & SVHR & SV
HR can increase up HR can increase up
to 190 bpmto 190 bpm
SV can increase up SV can increase up
to 103 to 113to 103 to 113

21. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 2121
Cardiac OutputCardiac Output
Other factorsOther factors
Venous return greatly Venous return greatly
increased byincreased by
 Activity in working Activity in working
musclesmuscles
Muscle pumpMuscle pump
Thoracic pumpThoracic pump
Mobilization of blood Mobilization of blood
from viscerafrom viscera
–VenoconstrictionVenoconstriction
Mobilization of blood Mobilization of blood
from reservoursfrom reservours

22. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 2222
Distribution of CODistribution of CO
TissueTissue At rest (ml/min)At rest (ml/min) Strenuous exercise Strenuous exercise
(ml/min)(ml/min)
BrainBrain 750 (13%)750 (13%) 750 (4%)750 (4%)
Heart Heart 250 (4%)250 (4%) 750 (4%)750 (4%)
Muscle Muscle 1,200 (20%)1,200 (20%) 12,500 (73%)12,500 (73%)
SkinSkin 500 (9%)500 (9%) 1,900 (11%)1,900 (11%)
KidneyKidney 1,100 (20%)1,100 (20%) 600 (3%)600 (3%)
Abdominal visceraAbdominal viscera 1,400 (24%)1,400 (24%) 600 (3%)600 (3%)
OthersOthers 600 (10%)600 (10%) 400 (2%)400 (2%)
TOTALTOTAL 5,8005,800 17,50017,500

23. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 2323
Distribution of CODistribution of CO
0
10
20
30
40
50
60
70
80
%

o
f

C
O
B
r a
i n
H
e
a
r t
m
u
s
c l e
s
k i n
k
i d
n
e
y
A
b
d
v i s
c e
r a
o
t h
e
r s
% of CO distribution at rest and during exercise
Rest
Exercise

24. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 2424
Local mechanism maintains a
high blood flow in exercising
muscles
Dilation of the arterioles and
precapillary sphincters cause
a 10-100-fold increase in the
number of open capillaries.
The capillary pressure
increases exceeding the
oncotic pressure throughout
the length of the capillaries.
Lymph flow is also increased
limiting the accumulation of
tissue fluid
Distribution of blood
flow at rest and during
heavy exercise
Oxygen
consumption of
skeletal muscle
increase 100-fold
during exercise

25. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 2525
Endurance AthleteEndurance Athlete
Resting CO = 5 L/minResting CO = 5 L/min
HR in highly trained HR in highly trained
athlete is much lower athlete is much lower
–Increased vagal toneIncreased vagal tone
–Decreased resting Decreased resting
sympathetic activitysympathetic activity
–HR = 40 to 50 bpmHR = 40 to 50 bpm

26. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 2626
Endurance AthleteEndurance Athlete
Resting CO of 5 Resting CO of 5
L/min is achieved L/min is achieved
–Increase in SV Increase in SV
–(CO = SV x HR)(CO = SV x HR)
–(5 = 100 x 50)(5 = 100 x 50)
Untrained Untrained
–(5000 = 71 x 70)(5000 = 71 x 70)
TrainedTrained
–(5000 = 100 x 50)(5000 = 100 x 50)

27. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 2727
0
50
100
150
200
SV rest HR rest SV ex HR ex
SV & HR of untrained and trained
untrained
trained
SV & HR in Trained and SV & HR in Trained and
Untrained Untrained

28. Aug 29, 2024Aug 29, 2024 circulation & exercisecirculation & exercise 2828
Endurance AthleteEndurance Athlete
During maximal During maximal
excise excise
CO of endurance CO of endurance
athleteathlete
–Can increase up to 35 Can increase up to 35
– 40 L/min– 40 L/min
Untrained Untrained
–(22,000 = 113 x 195)(22,000 = 113 x 195)
TrainedTrained
–(35,000 = 179 x 195)(35,000 = 179 x 195)