Exercise physiology is concerned with the study of how the body adapts physiologically to the acute stress of exercise or physical activity, and the chronic stress of physical training.

1. Dr. Abhijit Diwate (Associate Professor)
Cardio-Vascular & Respiratory PT
DVVPF College of Physiotherapy,
Ahmednagar 414111
EXERCISE PHYSIOLOGY
CARDIO – RESPIRATORY ADAPTATIONS

2. OBJECTIVES
 Introduction
 Bioenergetics
 Exercise metabolism
 Fuel selection in exercise
 Classification of exercise
 Changes with exercise
Cardiovascular system
Respiratory system

3. EXERCISE PHYSIOLOGY
 Exercise physiology is concerned with the
study of how the body adapts physiologically
to the acute stress of exercise or physical
activity, and the chronic stress of physical
training.

4. RESPONSES TO EXERCISE
 Acute responses
The responses to an individual bout of
exercise.
 Chronic adaptations
Response of body over time to the stress
of repeated exercise bouts.(training effects)

5. SOURCES OF ENERGY

6. EXERCISE METABOLISM
ANAEROBIC
AEROBIC
glycolysis oxydative
phosphorylation
PC breakdown

8. PHOSPHOCREATINE BREAKDOWN

9. OXIDATIVE PHOSPHORYLATION

10. ATP- ENERGY CURRENCY
 ATP is high energy phosphate
 ATP +H2O ADP +P + 7.3
Kcal/mole
 ATP is limited
85 gm of ATP is stored in the body at
any time.

11. CP/PC - ENERGY RESERVOIR
ATPase
ATP ADP +P + ENERGY
creatrin kinase
CP C + P + ENERGY

12. EXERCISE METABOLISM
 Rest to exercise transition
oxygen uptake increases rapidly reaching a
steady state(vo2max)
oxygen deficit- lag in oxygen uptake at
beginning of exercise
(failure of O2 uptake due to anaerobic
pathway)

13. FACTORS CONTRIBUTING TO OXYGEN
DEBT
 Resynthesis of PC in muscle
 Lactate removal
 Restoration of musle oxygen store
 Elevated body temperature
 Post exs increased HR and breathing
 Elevated hormone

14. METABOLIC RESPONSES TO
EXERCISE
 High intensity short term exs(2-20 sec)
ATP-PC system
 Intense exercise (>20 sec)
glycolysis
 High intensity(> 45sec)
ATP-PC, glycolysis, aerobic system
 Prolonged exercise(>10 min)
aerobic metabolism

15. INCREMENTAL EXERCISE
Used in cardio vascular fitness- VO2max
 VO2max plateau
 Lactate threshold

16. VO2MAX PLATEAU

17. LACTATE THRESHOLD

18. ENERGY GENERATING CAPACITY
 Factors affecting Max O2 uptake
Mode of exercise
Heredity
State of training
Gender
Body composition
Age

19. FUEL SELECTION IN EXERCISE
 Low intensity exercise(<30%Vo2 max)
- fats
 High intensity exercise(>70% V02max)
-carbohydrates

20. EXERCISE DURATION AND FUEL

21. CARDIO VASCULAR RESPONSES TO
EXERCISE

22.  CHANGES IN HEART
cardiac cycle
heart rate
cardiac output
 CHANGES IN PERIPHERAL CIRCULATION
blood pressure
blood flow
blood

23. CARDIAC CYCLE IN EXERCISE
systole diastole
(HR-75
bpm)
systole diastole
(HR-180
bpm)
greater reduction in diastole , systole less
affected.
.3sec .5sec
.2 sec
.13
sec
.2 sec
.13
sec

24. REGULATION OF HEART RATE
 Initial increase in HR (100 bpm)
withdrawl of parasympathetic
control
 At higher rates(>100bpm)
stimulation of sinuatrial node and
atrioventricular node by sympathetic control

25. CARDIAC OUTPUT
 Cardiac output(CO)
=Stroke volume (SV) × Heart rate(HR)
The rise in cardiac out put is largely due to rise in
heart rate .
Exeption
Untrained - In moderate exercise stroke volume
rises only mildly(10-30 %)
Trained – stroke volume rises sharply with moderate
exercise.

26. STROKE VOLUME

27. ADAPTATIONS IN PERIPHERAL
CIRCULATION
 Changes in
Blood pressure
Peripheral blood flow
Blood

28. CHANGES IN BLOOD PRESSURE
Isotonic exercises
 Systolic BP rises
 Diastolic BP falls
Isometric exercises
Both systolic and diastolic BP rise sharply.

29. BLOOD PRESSURE
 Mean arterial BP = CO × total vascular
resistance
↥ HR ↥ SV
↥ BP
↥ PERIPHERAL
RESISTANCE
↥ BLOOD
VISCOSITY
↥ BLD
VOLUME

30. PERIPHERAL CIRCULATION
 Vasodilatation in skeletal muscles(80%-
85%).
 Reduced splanchnic circulation (liver,
stomach, intestines)
 Reduced blood flow to kidneys

31. CARDIOVASCULAR DRIFT
 With prolonged exercise or exercise in hot
environment , at constant intensity:
 SV decreases
 HR increases
 Cardiac output well maintained( HR × SV)
 Arterial BP decreases.

32. CAUSES FOR CV DRIFT
 Vasodilatation in the skin to facilitate heat
loss and cool the body core temperature.
 Decrease in blood volume(sweating)
 Reduction in end diastolic volume

33. CHANGES IN BLOOD
 Oxygen content
Increased arterial- mixed venous oxygen
difference
(a-v)o2 difference.
This value represents the extent to which oxygen
is extracted (skeletal muscles)
 At rest
20 ml of oxygen per 100 ml of arterial blood
14 ml of oxygen per 100 ml of venous blood
so the (a-v)o2 difference is ….6 ml

34. RESPIRATORY CHANGES

35. PULMONARY VENTILATION
 Increase in rate and depth of respiration
 Initial respiratory adjustment to demands of
exercise is due to respiratory control centre in
brain (central command)
 Second phase of respiratory increase is due to
chemical status of arterial blood(increased CO2
and H+ detected by chemoreceptors,
stimulate respiratory centre

36. BREATHING IRREGULARITIES
DURING EXERCISE
 Dyspnea
 Hyperventilation
 Valsalva maneuver

37. VENTILATORY EQUIVALENT FOR
OXYGEN
 It is the ratio between the volume of air expired or
ventilated (VE) and the amount of oxygen
consumed by the tissues.(VO2)
 At rest : 23-28 L of air / L of oxygen.
 At mild exs: little change
 At high intensity: >30L of air /L of oxygen
 This ratio remains relatively constant at wide
range of exs – breathing matched to demands of
oxygen.

38. VENTILATORY THRESHOLD
 As exercise intensity increases, at a point
ventilation increases disproportionately to
oxygen consumption. That point is called
ventilatory threshold.
 Approximately 55% to 70% of VO2 max
 Due to increase in lactate production.

39. QUESTIONS
1. WRITE ABOUT OXIDATIVE
PHOSPORILATION. 5MARKS

40. SUMMARY
 Bioenergetics
 Exercise metabolism
 Fuel selection in exercise
 Classification of exercise
 Changes with exercise
Cardiovascular system
Respiratory system