INTRODUCTION TYPES OF EXERCISE - Dynamic exercise, static exercise AEROBIC AND ANAEROBIC EXERCISES METABOLISM IN AEROBIC AND ANAEROBIC EXERCISES SEVERITY OF EXERCISE- Mild exercise,„ moderate exercise, severe exercise EFFECTS OF EXERCISE- On blood, on blood volume, on heart rate, on cardiac output, on venous return, on blood flow to skeletal muscles, on blood pressure

1. CVS CHANGES DURING
EXERCISE
Pandian. M
Dept of Physiology,
D.Y.Patil Medical College, KOP
.

2. OBJECTIVES
• INTRODUCTION
• TYPES OF EXERCISE - Dynamic exercise, static exercise
• AEROBIC AND ANAEROBIC EXERCISES
• METABOLISM IN AEROBIC AND ANAEROBIC
EXERCISES
• SEVERITY OF EXERCISE- Mild exercise,„moderate
exercise, severe exercise
• EFFECTS OF EXERCISE- On blood, on blood volume, on
heart rate, on cardiac output, on venous return, on blood
flow to skeletal muscles, on blood pressure

3. INTRODUCTION
•A key requirements of CVF during exercise is to deliver
required metabolic needs of body tissues, particularly to
the exercising muscles.
Various adjustments in the body during exercise are
aimed at:
1. Supply of various metabolic requisites like
nutrients and oxygen to muscles and other tissues
involved in exercise
2. Prevention of increase in body temperature.

4. CARDIOVASCULAR RESPONSES TO
EXERCISE
1.Increase in the skeletal muscle blood
flow,
2.Redistribution of blood flow in the body,
3.Increase in the cardiac output,
4.Blood pressure changes and
5.Changes in the blood volume.

5. TYPES OF EXERCISE
Exercise is generally classified into two types
depending upon the type of muscular contraction:
1. Dynamic exercise - involves isotonic muscle
contractions. External work is involved in this type
of exercise.
2. Static exercise - involves isometric muscle
contractions.
Cardiovascular changes are slightly different in
these two types of exercise.

6. ANOTHER TYPES OF EXERCISE IS
Classification of exercise:-
•Mild – fast walking
•Moderate – slow and steady running
•Severe – 100 meter race
Isometric – heavy weight lifting etc.
Isotonic – walking, running, playing etc.
•Whole body exercise – jogging, running etc.
•Single limb exercise – lifting of a bucket with one arm etc.

7. CV CHANGES IN ISOTONIC EXERCISE
•HR ↑s proportionately with the severity of
exercise.
•CO ↑s due to ↑s in HR and SV
•Systolic pressure ↑s
•Diastolic pressure ↑s in mild exercise, does not
change or ↓s slightly in moderate exercise and
always ↓s in severe exercise.
•Blood flow to exercising muscle ↑s

8. CV CHANGES IN ISOMETRIC EXERCISE
•HR ↑s at beginning of exercises due to ↓s the Vagal
Tone. ↑d discharge of Cardiac sympathetic fibers may
also contribute.
• SV changes relatively little.
•SP and DP rise sharply.
•Blood flow to the exercising muscle ↓s (tonically the
muscles are contracted during isometric exercise )
•PR ↑s which ↑s DP significantly in isometric exercise.

9. AEROBIC AND ANAEROBIC EXERCISES
a. AEROBIC - exercises where one ‘huffs and puffs’ to
supply O2 to exercising muscles (its beneficial for CVS &
RS)
E.g. Jogging, cycling, spot running, swimming, skipping
rope, etc.
These exercises do not require excessive speed or
strength.
b. ANAEROBIC - exercises where O2 is not used for that
particular duration but high rate of work done in short period.
E.g - sprinting (These exercise do not long last)

10. 1. SKELETAL MUSCLE BLOOD FLOW

12. •The blood flow in calf muscle for a period of 6
minutes during moderately strong intermittent
contractions.
•Note not only the flow increase about 13-fold—
but also the flow decrease during each muscle
contraction

14. Two points can be made from this study:
1. The actual contractile process itself temporarily
↓s muscle blood flow.
•The contracting skeletal muscle compresses the
intramuscular blood vessels;
•Therefore, strong tonic muscle contractions can
cause rapid muscle fatigue.
•Because of lack of delivery of enough oxygen and
other nutrients during the continuous contraction.

15. BLOOD FLOW REGULATION IN SKELETAL MUSCLE
AT REST AND DURING EXERCISE
•Very strenuous exercise is one of the most
stressful conditions that the normal
circulatory system faces.
•This is true ! because there is such a large
mass of skeletal muscle in the body,
•all of it requiring large amounts of blood flow.

16. • Also, the CO often must increase in the
nonathletic to four to five times normal, or
•In the well-trained athlete to six to seven times
normal, to satisfy the metabolic needs of the
exercising muscles.

17. RATE OF BLOOD FLOW THROUGH THE
MUSCLES
•At rest, blood flow through skeletal muscle averages 3
to 4 ml/min/100 g of muscle.
•During extreme exercise in the well-conditioned athlete,
this can increase 25- to 50-fold,
•rising to 100 to 200 ml/min/100 g of muscle.
•Peak blood flows as high as 400 ml/min/100 g of muscle
have been reported in thigh muscles of endurance -
trained athletes.

19. THE ANSWER IS EQUALLY SIMPLE: TO DO THIS
WOULD REQUIRE MANY TIMES MORE BLOOD
FLOW THAN THE HEART CAN PUMP.
•One might ask the simple question:
•Why not simply allow a very large blood flow all the
time through every tissue of the body, always enough to
supply the tissue’s needs whether the activity of the
tissue is little or great?

20. 2. REDISTRIBUTION OF BLOOD FLOW

21. REDISTRIBUTION OF BLOOD FLOW
• Tremendous ↑s in the skeletal muscle blood flow is possible
due to increased cardiac output.
Coronary blood flow -
• A continuous flow of blood to the heart is essential to maintain
an adequate supply of O2 and nutrients.
• Normal coronary blood flow at rest is about 250 mL (70
mL/100 g tissue/min), i.e. about 5% of the resting CO (5 L).
• During exercise, coronary blood flow is increased by four to
five times with 100% O2 utilization.

22. •Visceral blood flow is temporarily reduced in co-ordination
with increase in muscle blood flow.
•It is brought about by the increased sympathoadrenal
discharge.
•Splanchnic blood flow is decreased by 80% in severe
exercise.
•Renal blood flow is also decreased by 50−80% in severe
exercise.
•Cerebral blood flow at rest is about 750 mL/min and
remains unchanged during any grade of muscular exercise.

23. • Adipose tissue blood flow is increased by four times during
exercise.
• This helps to deliver fatty acids mobilized from triglyceride stores
to the working muscles.
Cutaneous blood flow at rest is about 500 mL/min.
• Decrease in beginning of exercise due to reflex vasoconstriction.
• Increase in sustained exercise when body temperature rises,
• To dissipate the heat generated during exercise, the blood flow
through
• The skin is controlled predominantly by the requirements of
temperature regulation.

25. 3. INCREASE IN CARDIAC OUTPUT

26. INCREASE IN CARDIAC OUTPUT
•The interrelations among :- work output, oxygen
consumption, and cardiac output.
•The muscle work output increases oxygen
consumption,
•Increased oxygen consumption in turn dilates the
muscle blood vessels,
•Thus increasing venous return and cardiac output.

29. EFFECT OF TRAINING ON HEART HYPERTROPHY AND
ON CARDIAC OUTPUT.
1.Marathoners can achieve max.CO about 40 %
greater than those achieved by untrained persons.
2.The heart chambers of marathoners enlarge about
40 % along with the heart mass also ↑s 40% or
more.
3.So that heart of the marathoner is considerably
larger than that of the normal person.
4.Not only do the skeletal muscles hypertrophy
during athletic training, but so does the heart.

30. 5. Heart enlargement and ↑d pumping capacity occur in
the endurance types, not in the sprint types, of athletic
training.
6. Resting CO normal as it is, but normal CO is
achieved by a large SV at a reduced heart rate.
7. The heart-pumping effectiveness of each heartbeat is
40 to 50 % greater in the highly trained athlete than in
the untrained person,
8. But there is a corresponding decrease in heart rate at
rest.

31. Comparison of Cardiac Function Between Marathoner and Nonathlete

32. ROLE OF STROKE VOLUME AND HEART RATE IN
INCREASING THE CARDIAC OUTPUT.
•changes in SV and HR as the CO ↑s from its resting
level of about 5.5 L/min to 30 L/min in the marathon
runner.
•The stroke volume ↑ses from 105 to 162 milliliters, an
increase of about 50%, whereas the heart rate ↑ses from
50 to 185 beats/min, an increase of 270 percent

34. FACTORS CONTRIBUTING TO TACHYCARDIA DURING
EXERCISE ARE:
1.Increased sympathetic discharge.
2.Peripheral reflexes originating from the
exercising muscles (muscle spindles, muscle-
tendon receptors and organ of Corti) and joints.
3.Local metabolic factors - Muscle tissue has free
nerve endings which are stimulated by the
LA,K+ ions and other metabolites contribute to
the sustained ↑ in HR during prolonged exercise.

35. 4. Humoral factors - such as release of adrenaline
and noradrenaline and possibly TH during exercise.
5. Intrinsic factors - Stimulation of SA node due to
↑d venous return, which ↑s the HR during exercise.
This is known as Bainbridge reflex.
6. Increased temperature in the myocardium due
to ↑d activity of the heart during exercise may
directly ↑s the rhythmicity of the pacemaker.

36. INCREASE IN STROKE VOLUME
Mechanisms responsible for increase in stroke volume
- It has been stated that an increase in the stroke
volume during exercise occurs due to gearing up of both
the control mechanisms,
•i.e.
•Intrinsic autoregulation or Frank–Starling mechanism
•Extrinsic regulation or autonomic and neural mechanism

37. 4. BLOOD PRESSURE CHANGES DURING EXERCISE

38. BLOOD PRESSURE CHANGES DURING
EXERCISE
In systemic circulation
•Systolic blood pressure is always raised by exercise
since it depends upon the cardiac output which is
increased in exercise.
•The BP remains elevated during exercise and
•It is not reflexly corrected by baroreceptor reflex.
•The fact that the neurons descending from the
hypothalamic defense Centre inhibit the baroreceptor
afferents.

39. •Diastolic blood pressure which primarily depends upon
the PR may mildly ↑ or ↓ or remain unchanged
depending upon the change in total peripheral
resistance.
•Mostly, the vasodilatation in the skeletal muscles
balances the vasoconstriction in other tissues,
•so diastolic blood pressure is usually not changed much.

40. IN PULMONARY CIRCULATION
•Systolic blood pressure in the pulmonary artery
may rise during heavy exercise to 25−30 mm Hg
from 15−20 mm Hg at rest,
• Diastolic blood pressure may rise from 5−8 mm
Hg at rest to 8−10 mm Hg and
• Mean blood pressure may reach to 15 mm Hg
from 8–12 mm Hg at rest.

41. 5. CHANGES IN BLOOD VOLUME DURING EXERCISE

42. CHANGES IN BLOOD VOLUME DURING
EXERCISE
•Blood volume during exercise is decreased by 15%
resulting in haemoconcentration.
•Blood volume is decreased due to more plasma loss at the
capillary level due to following reasons:
1. Increased hydrostatic pressure in capillaries and
2.Increased tissue fluid osmotic pressure due to
accumulation of osmotically active metabolites in tissue
spaces such as potassium, phosphate and lactic acid.

43. • Relation of Cardiovascular Performance to Vo2 Max.

44. EFFECT OF HEART DISEASE AND OLD AGE
ON ATHLETIC PERFORMANCE.
•One can readily understand that any type of heart
disease that reduces maximal cardiac output
•will cause an almost corresponding decrease in
achievable total body muscle power.
•Therefore, a person with congestive heart failure
frequently has difficulty achieving even the muscle
power required to climb out of bed, much less to walk
across the floor

45. •The maximal CO of older people also decreases
considerably.
•There is as much as a 50 % decrease between ages 18
and 80.
•Also, there is even more decrease in maximal breathing
capacity.
•For these reasons, as well as reduced skeletal muscle
mass,
•The maximal achievable muscle power is greatly
reduced in old age.

50. THANK YOU . . .