2nd and 3rd September 2011,a General Lecture Theatre, Dr Chirantan Mandal, Dr Avik Basu, Dr Dipayan Sen Dr Ushnish Adhikari,Dr Srimanti Bhattacharya, Dr Shubham Presided by Dr Arnab Sengupta (Physiology Dept Medical College Kolkata)
RESPIRATORY RESPONSE TO EXERCISE by DIPAYAN SEN 3 RD YEAR MEDICAL COLLEGE, KOLKATA
Respiratory system: Its significance in exercise <ul><li>EXERCISE </li></ul>1. Anaerobic Exercise 2. Aerobic Exercise Respiration is of relatively little concern Respiration is critical for maximal performance
Oxygen Consumption in Exercise (VO 2 max) CONDITIONS MAXIMAL OXYGEN CONSUMPTION (ml/min) Untrained average male 3600 Athletically trained average male 4000 Male marathon runner 5100
Limits Of Ventilation Abnormalities in the respiratory system Special conditions Exercise at high altitudes Exercise under very hot conditions Pulmonary Ventilation at maximal exercise 100-110 L/min Maximal Breathing Capacity 150-170 L/min
Changes In Ventilation During Exercise The pO 2 of arterial blood drops from 40mm to <25mm Hg Blood flow per min rises from 5.5 L/min to 20-35 L/min Recruitment of new capillaries at tissue level Increased O 2 delivery to tissues
<ul><li>Ventilation </li></ul><ul><li>Increases abruptly with the onset of exercise </li></ul><ul><li>More gradual increase. </li></ul>
Increase in ventilation Increased oxygen demand Increased body temperature Increased plasma potassium levels Increased neural sensitivity to partial pressure of CO 2 Increased plasma H + ion concentration Role of O 2 ???
Mainly shows increase in both rate and depth of respiration Mainly shows increase in depth of respiration Exercise Moderate exercise Severe exercise
<ul><li>Oxygen Diffusing Capacity </li></ul><ul><li>Fick’s law of diffusion </li></ul><ul><li>V gas =A/T x D x (P1 – P2) </li></ul><ul><li>V gas = rate of diffusion A = tissue area T = tissue thickness D = diffusion coefficient of gas P1 – P2 = difference in partial pressure </li></ul>
Maximal O 2 diffusing capacity of different persons Nonathlete at rest 23 mL/min Nonathlete during maximal exercise 48 mL/min Speed skaters during maximal exercise 64 mL/min Swimmers during maximal exercise 71 mL/min Oarsman during maximal exercise 80 mL/min
<ul><li>Maximal Exercise </li></ul><ul><li>Increased blood flow through the lungs </li></ul><ul><li>All the pulmonary capillaries are perfused at their maximal rates </li></ul><ul><li>A far greater surface area available through which oxygen can diffuse into the pulmonary capillary blood </li></ul>Increased diffusion capacity of O 2
Oxygen-Haemoglobin Dissociation Curve in Exercise ........... CURVE IN EXERCISE ……… . NORMAL CURVE
Fatigue of respiratory muscles <ul><li>Do respiratory muscles fatigue during exercise? </li></ul>Yes they do!!!
Effect of Smoking on Pulmonary Ventilation in Exercise SMOKING (Nicotine and other irritants) Constriction of the terminal bronchioles Increases the resistance of airflow Increased fluid secretion and mucosal oedema Paralyses the mucociliary escalator system