concise view of respiration during exercise

2. Content
 Mechanism of ventilation
 Lung volumes and capacity
 Factors affecting lung volumes
 Pulmonary ventilation
 Regulation of ventilation
 Regulation during exercise
 Ventilation during exercise
 Variation from normal breathing
 Article discussion
 Conclusion

3. Anatomy of Ventilation
 Pulmonary ventilation is a process of
exchanging gases
 Air enter through nose and mouth travel
through conductive system
 Reaches the alveoli for gaseous
exchange

4. Anatomy of Ventilation
At rest 1 RBC remains in pulmonary capillary only 1 secs
At max exc 1 pint of blood flows thr lung tissue bld vessels

5. Anatomy of ventilation
 Ventilatory system divides into
1. Conductive zone
2. Respiratory zone 1. Air transport
2. Humidification
3. Warming
4. Particle filtration
5. Immunoglobulin secretion
1. Surfactant production
2. Molecule activation and
inactivation
3. Blood clotting regulation
4. Endocrine function

6. The Alveoli
 600 million
 0.3mm
At Rest:
250 ml of O2 leaves alveoli and 200 ml of Co2 diffuses
At high intense exercise: 25 times higher

7. Mechanism of Ventilation
 Inspiration
 is an active process of the diaphragm and the
external intercostal muscles.
 air rushes in into the lungs to reduce a pressure
difference.
 During exercise, forced inspiration is further assisted by the
scalene, sternocleidomastoid, and pectoralis muscles.

8. Mechanism of ventilation
 Expiration
 is a passive relaxation of the inspiratory muscles and
the lung recoils.
 increased thoracic pressure forces air out of the lungs
 During exercise, forced expiration is an active process
of the internal intercostal muscles (latissimus dorsi,
quadratus lumborum & abdominals).

9. LUNG VOLUMES AND CAPACITY

10. Static Lung volumes
In athletes ?

11. Static Lung volumes
 Athletes with larger lung volumes
reflects the genetic influences
 Exercise training does not increase the
static lung volumes

12. Dynamic lung volumes
a) Forced vital capacity
b) Maximum voluntary ventilation
c) Minute ventilation
 Depends on two factors:
1. Max stroke volume of lungs
2. Speed of moving a volume of air

13. Maximum voluntary ventilation
 MVV: Evaluates ventilatory capacity with
rapid and deep breathing for 15 secs
 Ventilatory training increases MVV

14. Is there difference in lung
volumes between different
groups?

15. Is there difference in lung volumes
between different sports?
 Swimming and diving has larger
volumes than normal static volumes
 Inspiratory work against additional
resistance

16. Factors affecting lung volumes
Genetic
Gender
Body
composition

17. Pulmonary ventilation
 One can view pulmonary ventilation in
two perspective:
1. Minute ventilation
2. Alveolar ventilation

18. Pulmonary ventilation
1. Minute Ventilation
Volume of air breathed each minute
 During exc both rate and TV increases
 In male endurance athletes can increase
upto 160L/m
 Professional football players have 200L MV

19. Pulmonary ventilation
2. Alveolar Ventilation
 Refers to the portion of minute ventilation
that mixes with the air in the alveolar
chambers.

20. Pulmonary ventilation
• Ventilation increases during exercise in
proportion to the metabolic needs
• Rapid increase in ventilation and tidal volume
• Increase can begin even before exercise starts

21. Ventilation during exercise
 In steady state exercise: light to mod exc
 Ventilation increases linearly with O2
consumption and Co2 production
 In this state ventilation increases by
increasing the tidal volume
 Ventilatory equivalent:
 Normal healthy young adult maintains 25(ie
25 L of air breathed/ lit of O2 consumed )
Ventilatory equivalent: Is the ratio of minute ventilation to O2 consumption

22. Ventilation during exercise
 In Non - steady state exercise: high
intensity exercise
 Ventilatory equivalent can attain: 35 – 40L
 In this state ventilation increases by
increasing the frequency of ventilation

23. Ventilatory threshold (Vt)
 The point at which pulmonary ventilation
increases disproportionately with O2 consumption
during graded exc
Excess ventilation due to Co2 release from the buffering of lactic acid

24. Regulation of ventilation during exercise
1. Chemical control
2. Non chemical control

25. Chemical control
High intensity exercise
Co2 and H+ conc is high
Ventilatory stimulus
Results in hyperventilation
Co2: 25mm/Hg

26. Non- chemical control
Neurogenic
factor
Cortical Peripheral

27. Regulation during exercise
 During exercise there is combined effect
of both Chemical and Neural stimuli

28. Regulation during exercise
 Phase 1: Start of exercise
 Neurogenic stimulation from cerebral cortex
and from the active limbs

29. Regulation during exercise
 Phase 2: Approximately after 20 secs
 Minute ventilation increases exponentially and
reaches the steady state
 Central, medullary and peripheral
chemoreceptors contributes to regulation

30. Regulation during exercise
 Phase 3:
 Involves fine tuning of steady state of ventilation through
peripheral sensory feedback mechanism
 Co2 and H+ maintains the ventilation in this phase

31. Regulation during exercise
 Recovery:
 Abrupt decrease in ventilation when exc ceases
is due to removal of central and peripheral
stimulus

32. Acid-base regulations
 Normal pH: 7.35 to 7.45
 Decrease in H† conc leads to alkalosis
and vice versa
 During exercise, body slightly acidic
 6.6 to 6.9
 Lower pH = Acidosis

33. Acid-base regulations
 3 mechanism regulate pH of internal
environment
1. Chemical buffers
2. Pulmonary ventilation and
3. Renal function

34. Pulmonary ventilation
H† conc ↑
Stimulates Res
center
Increase in
Alveolar ventilation
Removes Co2 from
blood

35. Variations from normal
breathing pattern
Hyperventilation
Dyspnea
Valsalva
maneuver

36. Hyperventilation
Increase in ventilation
Increase O2 consumption
and CO2 elimination
Accompanying decrease
in H+
Decrease in pH

37. Hyperventilation
 The primary urge to breathe is triggered
by rising CO2 in blood

38. Hyperventilation

39. Valsalva Maneuver
 Refers to forceful expiration against
closed glottis
 Prolonged Valsalva maneuver
decreases blood supply to brain
 May cause fainting or dizziness

40. Valsalva maneuver

41. Respiratory Responses:
Limitations to Performance
 Ventilation normally not limiting factor
 Respiratory muscles account for 10% of VO2
 Respiratory muscles very fatigue resistant
 Airway resistance and gas diffusion
normally not limiting factors at sea level
 Restrictive or obstructive respiratory
disorders can be limiting

42. Respiratory Responses:
Limitations to Performance
 Exception: elite endurance-trained athletes
exercising at high intensities
 Ventilation may be limiting
 Ventilation-perfusion mismatch
 Exercise-induced arterial hypoxemia (EIAH)

43. ARTICLE DISCUSSION

44. Does the Respiratory System Limit Exercise in Mild
Chronic Obstructive Pulmonary Disease?
 Roberto C. Chin1, Jordan A. Guenette1,2, Sicheng Cheng1, Natya
Raghavan1,3, Naparat Amornputtisathaporn1,4,
 Arturo Corte´s-Te´lles1, Katherine A. Webb1, and Denis E. O’Donnell1
Department of Medicine, Queen’s University
AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE 2013

45. Aim
 To compare the effects of DS loading
during exercise on ventilation, breathing
pattern, operating lung volumes, and
dyspnea intensity in subjects with mild
symptomatic COPD

46. Methods
 Twenty subjects with Chronic
Obstructive Lung Disease stage I COPD
and 20 healthy subjects completed two
symptom-limited incremental cycle
exercise tests, in randomized order:
unloaded control and added DS of 0.6 L.

47. Results
 These results show that the respiratory
system reached or approached its
physiologic limit in mild COPD at a lower
peak work rate and ventilation than in
healthy participants

48. Effects of respiratory muscle
work
on exercise performance
CRAIG A. HARMS,THOMAS J. WETTER,
CLAUDETTE M. ST. CROIX,DAVID F.
PEGELOW, AND JEROME A. DEMPSEY
Journal of Appl Physiology
feb/2000

49. Aim
 The work of breathing normally
experienced during strenuous exercise
would impair exercise performance.

50. Results
 Major Findings
 Decreasing the work of breathing
consistently led to significantly longer
exercise tolerance
 whereas increasing the work of
breathing decrease performance

51. Conclusion