Acute effect of steady level exerise on vital parameters

Dr.NIKITA MANJANWAL
(MPT Orthopedics))

Introduction
Aerobic exercise
Post exercise oxygen consumption
Effect on heart rate
Effect on blood flow
Effect on blood pressure
Effect on respiratory rate
Effect on temperature
Effect on acid base balance.

When we begin to study exercise physiology ,
we must first learn how body respond to
single bout of exercise which is called acute
response.
Many factors can alter body’s acute responses
to a bout of exercise.

As the body shifts from rest to exercise the
energy need is increased.
Steady level is a state at which O2
consumption requires several minutes at
which the aerobic process are fully functional,
but body’s oxygen requirement increases
immediately when exercise begins.

A state obtained in moderate muscular
exercise when removal of lactic acid by
oxidation keeps pace with its production.
Pertaining to the time period during which a
physiological functions remains constant is
called steady state.

Aerobic exercise is augmentation of energy
utilization of muscle by means of an exercise
program.
Training produce cardiovascular or muscular
adaptations which is reflected in an
individual’s endurance.

A carefully planned exercise program results
in higher level of fitness.
There are 3 components of exercise program
1) a warm up period
2) aerobic exercise period
3) cool down period

A time lag exist between onset of physical
activity and bodily adjustments needed to
meet the physical requirements.

There is increase in muscle
temperature.
Extraction of hemoglobin is greater at
higher muscle temperature.
Dilatation of previously constricted
capillaries with increase in circulation &
minimizing lactic acid formation

 To enhance the numerous adjustments that
must take place before physical activity.
To decrease the susceptibility of
musculoskeletal system injury.
To prevent occurrence of ischemic (ECG)
changes and arrhythmias.

This exercise period is conditioning part of
exercise program.
Exercise must be in patient’s tolerance , above
threshold level for adaptation to occur and
below the level of exercise that evokes clinical
symptoms.

The intensity be great enough to stimulate an
increase in stroke volume , cardiac output
,and to enhance local circulation.
These are generally submaximal, repetitive
and rhythmic.

Continu
ous
training
Circuit
training
Interval
training
Circuit
interval

The purpose is to:
1) Prevent pooling of blood in extremities by
continuing to use the muscles to maintain
venous return.
2) Prevent fainting by increasing the return of
blood to heart and brain as cardiac output and
venous return decreases.

3) Enhance the recovery period with oxidation
of metabolic waste.
4) To prevent MI , arrhythmias etc.

Oxygen consumption requires several minutes
to reach steady state, body’s oxygen
requirement increase immediately the
moment exercise begins.
Because O2 needs and its supply differ during
transition from rest to exercise..there occurs
OXYGEN DEFICIT.

Oxygen Deficit= (oxygen requirement-
oxygen consumed).

Despite insufficient oxygen, muscle still
generate the ATP needed through anaerobic
pathway(ATP-PC system , glycolysis).

After exercise during initial minutes even
though muscles are no longer
working..demand for oxygen does not
immediately decreases.
Instead oxygen consumption remains elevated
temporarily.

This consumption , which exceeds usually
required oxygen when at rest is referred as
OXYGEN DEBT.
The common terminology used is excess
postexercise oxygen consumption [EPOC].

The EPOC is the volume of oxygen consumed
above normally consumed at rest.
Recent studies have given a classical
explanation about EPOC.

During initial phase some oxygen is borrowed
from oxygen stores(hemoglobin and
myoglobin).
That oxygen must be replenished during
recovery.

Also respiration remains temporarily elevated
following exercise ..in an effort to clear CO2
that has accumulated in tissues as –a –by
product.
Also body temperature is increased which
keeps metabolic and respiratory level high
hence requiring more oxygen.

Increase H.R
and breathing
Increase body
temperature
Restoration of
muscle and
oxygen store
Lactate
conversion to
glucose
Elevated
hormone
Re-synthesis
of PC system

Steady state exercise have mainly effect on
following parameters:
Heart rate ,
blood pressure
Blood flow
Respiratory
rate ,
temperature
Acid base
balance
fluid
electrolyte
balance

Acute effect of steady level exerise on vital parameters

Studies have monitored, O2 consumption of
heart has shown that heart rate both at rest
and during exercise is good indicator of how
hard heart is working.
As active muscle require more oxygen than
resting muscle..heart O2 consumption and
amount of work it does is directly related to its
contraction rate.

Measuring involves taking person’s pulse,
usually radial or carotid artery sites.
Resting heart Rate: It averages from 60-
80beats/min.
In highly conditioned athletes RHR ranges
from 28-40 beats/min.

Heart rate during exercise: When we begin
exercise HR increases directly in proportion to
increase in exercise intensity until you are
near the point of exhaustion.
At this point your HR begins to level-off. This
indicates you are approaching maximum HR.
HRmax: 220-(AGE IN YEARS)
HRmax: 208-(0.7* AGE IN YEARS)

When the rate of work is held constant at
submaximal level of exercise , HR increases
rapidly until it reaches a plateau..this plateau
is the steady-state heart rate.
It is the optimal heart rate for meeting the
circulatory demands at specific rate of work.

Drift: when exercise is performed at constant
rate over prolonged period of time,
particularly under heat stress, HR tends to
drift upwards instead of maintaining its
steady-state value.
Here stroke-volume(SV) gradually decreases
and HR increases.

With moderate exercise heart rate increases to
140 beats/min.
Even the thought of exercise increases rate.
Increased heart rate is also mainly because of
vagal withdrawal.

Impulses from
proprioceptor
s in
exercising
muscles act
through
higher center
CO2 acts
Through
Medullary
centers
Rise in body
temperature
acts on
cardiac center
via
hypothalamus
..also
stimulates SA
node
Circulating
catecholamin
e which are
secreted in
large quantity

A= ANTICIPATORY RISE
B= SHARP RISE
D= STEADY STATE
E= RAPID DECLINE
F= SLOWER RECOVERY

When examining blood pressure during
exercise , systolic and diastolic must be
distinguished because they show different
changes.
With exercise systolic B.P starts out at
120mmHG and exceed up to 200mmHG.

Increased systolic pressure results from
increased cardiac output that accompanies
increased rate of work.
Also blood pressure determines how much
fluid leaves the capillaries, entering the tissues
and carrying needed supplies. It facilitates
delivery process.

Diastolic pressure changes little, regardless of
intensity. It represents pressure in arteries
when at rest.
Blood pressure reaches a steady state during
submaximal steady state exercise.

If steady state is prolonged , the systolic
pressure might start to decrease gradually, but
diastolic pressure remains constant.
This decrease in systolic pressure, if it occurs
in normal response reflect arterial dilation in
active muscles
B.P= CARDIAC OUTPUT * PERIPHERAL
RESISTANCE

We know that active muscle needs more
oxygen and nutrients..to meet these blood
must be brought into these muscles during
exercise.
During exercise metabolic rate of muscle
tissue increases and begins to accumulate.

At resting condition blood supply is 3-
4ml/100 grams of muscle per minute.
It increases up to 60-80ml in moderate steady
state exercise.

With steady state exercise the muscles become
better trained and cardiovascular system gets
adapts to increase blood flow.
Through the action of sympathetic nervous
system, blood is redirected away from areas
where it not essential(digestive system ,
kidneys) to areas which is active during
exercise.

Sympathetic Sympathetic
Stimulation to Stimulation to
Constrictor fiber Vasodilator fiber
Decreases Increases
additional blood
flows

The metabolic rate of muscle tissue increases ,
as a result more metabolic waste product
begins to accumulate.
Increased metabolism causes increase in
acidity , CO2 , temperature in muscles. These
local changes trigger vasodilatation increasing
blood flow.

Factor
enhancing
Blood flow
More
effective
redistributi
on
Greater
opening of
capillaries
Increased
blood
volume
Increased
capillarizatio
n

The onset of physical exercise is accompanied
by two phase increase in ventilation
An immediate,marked increase occur
followed by more gradual increase.
• [1]
The second phase increase is produced
by changes in temperature & chemical
status of arterial blood.
• [2]

As exercise begins , but before any chemical
stimulation occurs , the motor cortex becomes
more active and transmit stimulatory impulses
to inspiratory center , which respond by
increasing respiration.

Proprioceptive feedback from active skeletal
muscle and joints provide additional input
about the movement and respiratory center
can adjust its activity accordingly.

As exercise progresses , increased metabolism
in muscles generates more heat , CO2 , and
H+.
This is sensed by chemoreceptors which in
turn stimulate the respiratory center,
increasing depth and rate of respiration.

Some data suggest that receptors in right
ventricle of heart sends information to the
inspiratory center to increase the cardiac
output , which can stimulate breathing during
early minutes of exercise

During mild steady state exercise ventilation
appears to match the rate of energy
metabolism.
The ratio between volume of air ventilated(VE)
and amount of oxygen consumed by
tissues(VO2) in given amount of time is called
ventilatory equivalent for oxygen

This ratio relatively remain constant over
steady state exercise..which means breathing
is properly match to body’s need for oxygen.
At rest it ranges from 23-28L of air per liter of
oxygen consumed.
There occurs a little change during mild
exercise .

DYSPNEA:
Shortness of breath
occur when there is
increase in arterial
CO2 and H+,
because of inability
to readjust the
blood PCO2 and
H+.
HYPERVENTILA—
TION:
Due to anxiety or
respiratory disorder
there is sudden
increase in
ventilation that
exceeds metabolic
needs which results
in alkalemia.
VALSALVA
MANEUVER:
There is increase in
intrathoracic and
intra-abdominal
pressure..which
restricts the venous
return and can
decrease cardiac
output.

The
area(alveol,bronch
ioles) are
stretched
excessively—to
expiratory center
The expiratory
center responds by
shortening duration
of inspiration
Hering-breuer reflex

Blood pH can change from moderate to high
intensity exercise.
Muscular activity results in production and
accumulation of lactate and H+ which can
impair energy production and reduce
contractile force.

Maintaining homeostatic balance in blood
PO2 , PCO2 and pH requires high degree of
coordination between respiratory and
circulatory systems.
Chlorine is an important mineral in
maintaining blood acid-base balance.

Body fluids have more bases(bicarbonate,
phosphates , proteins) than acids under
resting condition that results in pH range from
7.1 to 7.4 in muscles.
Even hemoglobin acts as a buffer.

 Body’s regulation of acid-base involves more
control of respiration.
 Acid such as lactic acid and carbonic acid release
H+ in body.
 To minimize effect of free H+, the blood and
muscles contain base substance to neutralize its
effect.
 H+ + buffer H-buffer.

Blood pH can change significantly , becoming
more acidic from slightly alkaline resting
value of 7.4 down to 7.0 .
The decrease in pH results from increased
blood lactate accumulation.

The pH is kept within relatively narrow range
by :
Chemical Buffers
Pulmonary
Ventilation
Kidney
Function

Majority of CO2 is carried in form of
bicarbonate ions.
CO2 + H2O H2CO3 H+ + HCO3-
(carbonic (bicarbonate)
acid)

H+ combines with hemoglobin and this
binding triggers Bohr’s effect.
Hence formation of bicarbonate enhance
oxygen unloading and hemoglobin act as a
buffer preventing any acidification of blood.

When this blood enters the lungs where PCO2
is lower H+ and bicarbonates rejoin to form
carbonic acid which then split in Co2 and
H2O.
 H+ + HCO3- H2CO3 CO2+H2O

Humans are homoeothermic , which means
internal body temperature is kept nearly
constant.
The normal range..of 36.1 to 37.8 degree
Celsius is deviated during prolonged heavy
exercise , illness or extreme condition of heat
or cold.

During exercise metabolic needs are increased
hence heat is generated..to maintain internal
body temperature , heat produced in your
body must have access to outside world.
It takes place through following process:

Evaporation.
Radiation.
Conduction/Conve
ction.

Conduction:
Convection:
Radiation:
• It involves the transfer
of heat from one
material to other
through molecular
contact.
• It involves moving
heat from one place to
other by motion of gas
or liquid across heated
surface.
• It is the primary
method for
discharging body’s
Excess heat. Skin
constantly radiates
heat.

It is the primary process of heat dissipation
during exercise.
80% of heat loss occurs through evaporation
when you are physically active.
As body temperature increases sweat
production increases.

Exercise
Body
temperature
increases
Sweat
production
increases
Sweat
reaches skin
It is
converted
from liquid to
vapor

As sweat reaches the skin it is converted from
a liquid state to a vapor by heat from skin.
Mechanism %loss Exercise Kcal/min
Conduction 15 2.2
Radiation 5 0.8
Evaporation 80 12.0
Total 100 15.0

Here we define cold stress environment
condition that causes a loss of body heat that
threatens homeostasis.
The hypothalamus has a temperature set at
37*C.
A decrease in skin or blood temperature
provide feedback to activate mechanism to
conserve body heat.

Shivering: a rapid, involuntary cycle
of contraction and relaxation-cause 4
to 5 times body’s heat production
Non shivering thermogenesis:
stimulation of metabolism by
sympathetic nervous system causing
increased heat production
Peripheral vasoconstriction: occurs as a
result of sympathetic stimulation of smooth
muscle surrounding arterioles in skin which
reduces blood flow to and prevent
unnecessary heat loss. Metabolic rate of skin
cells decreases.

Water constitute about 50%-60% of total body
weight.
It is referred to as intracellular fluid.
While extracellular fluid include water+blood
plasma , lymph, and some other fluids.

• Blood
plasma is
determi--
nant of B.P
• Keeps body
hydrated
during
exercise
• Hormonal
transport
that
regulate
metabolis
m
• RBC carry
oxygen to
active
muscle Nutrients,
glucose,
amino acid
are
transport
CO2 &
other
metabolic
waste
leaves
body
Water
facilitates
dissipation
of body
heat.
Body fluid
contains
buffering
agents to
maintain
pH.

Water loss accelerates during exercise..and it
depends on the formation and evaporation of
sweat.
As body’s temperature increases, sweating
increase in an effort to prevent overheating.

Water loss occurs from 4 sources:
1. Evaporation from skin
2. Evaporation from respiratory tract
3. Excretion from kidney
4. Excretion from large intestine

Water is also produced during exercise
because of oxidative metabolism.
The amount of sweat produced during
exercise depends on
*environment,temperature,humidity
*body size
*metabolic rate

Water at same time is produced by oxidative
metabolism , unfortunately the amount
produced has small impact on dehydration ,
water loss etc…
Example: a 70kg person metabolize about
245g of carbohydrate , this would produce
636 g of water , during this time sweat loss
could exceed 1500ml of water.

Normal body function depends on balance
between water and electrolytes.
When large amount of water is lost during
exercise balance between water and
electrolytes is disrupted quickly.

Human sweat is infiltrate of blood plasma, so
it contains.
* Sodium(Na)
* Chloride(Cl)
* Potassium(K)
* Magnesium(Mg)
* Calcium(Ca)

At elevated rates of sweating during steady
state exercise, loss of sweat would lower
body’s sodium and chloride content by 5% to
7%.
Sodium and chloride are predominant ions in
sweat and blood.

To clear waste from blood and regulating
water level kidneys also regulate body’s
electrolyte content.
Urine production is major source.
Body’s water loss increase during exercise;
urine production rate decreases in an effort to
conserve water.

 The function of sodium is to maintain osmotic
pressure ; nerve and muscle function.
 Hence deficiency would cause nausea, vomiting,
exhaustion and dizziness.
 Chloride imbalance will cause acid-base
imbalance in body.
 Electrolytes loss during exercise occurs primarily
with from water loss during sweating.

Wilmore
Kisner
Mccardle
Sembulingam

Acute effect of steady level exerise on vital parameters

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Acute effect of steady level exerise on vital parameters