1. Assistant Prof: Nermine Mounir Riad Ain Shams University, Chest Department

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5.  Oxygen is consumed in the production of ATP and that co2 is produced as waste product. Respiratory quotient(RQ) this ratio of o2 consumption to co2 production.  It equals 0.8

6.  Takes place by means of diffusion of substances. External respiration:(within the lungs)  Respiratory exchange ratio(R) is the ratio of this exchange within the lungs between oxygen and carbon dioxide. R= 200/250=0.8 Internal respiration:(within the muscles) Gas exchange and nutrients.

7. 1- The fuel needed for ATP production must be supplied. 2-waste products that result from ATP production must be removed.

8. Metabolism parameters: 1-oxygen consumption: -Normally at rest average 250 ml/min (3.5-4 ml/min/kg), with exercise it will increase directly with the level of muscular work, VO2 increase until exhaustion occurs and maximum level of O2consumption(VO2max) is reached. -VO2 max is a reproducible, well defined physiologic end point so it is used as a definitive indicator of an individual s muscular work capacity. Normally range from 1700-5800 ml/ min

9. 2- CO2 production:  Normally 200ml/min (2.8 ml/min/kg)  During the initial phase of exercise it increase at a rate similar to VO2, once the anaerobic threshold has been reached, VCO2 increases at a faster rate than VO2. the faster rate is the result of additional CO2 production from HCO3/CO2 buffering mechanism.

10. 3-Anaerobic threshold:  In normal individuals occurs at approximately 60% ± 10% of the persons VO2 max.  At the onset of the AT, there is marked increase in CO2 production because of lactic acid buffering and a compensatory increase in ventilation.  After the onset of the AT, a breathlessness develops and a burning sensations begins in working muscles.

11. 4-Respiratory Quotient:  CO2 production ↑ during exercise esp. after the AT has been achieved →↑ RQ from resting levels of 0.8 to beyond 1.0  The subject will be able to continue exercise for a short period of time as much as 1.5 5-Blood PH:  Remains relatively unchanged till the onset of AT → the blood gradually becomes more acidotic as the body is less able to buffer the excessive acid (H)produced by anaerobic metabolism.

12. 1-Minute Ventilation:  Normally = 5-6 l/min,100l/min in maximal exercise.  At the very start of an exercise → vent. ↑ (d.t. resp. centers stimulation by the brain motor cortex and joint proprioceptors)  Humeral factors (chemoreceptors) do the fine tuning of vent.  The level of vent. Continue increasing correspondingly with the increase of the workload till AT reached → vent. ↑ in a rate greater than the rate of workload ↑ to compensate for the additional C02 produced during anaerobic metabolism.

13. 2-Tidal volume:  Normally = 500 ml, 2.3-3 L during exercise  Increase early in exercise and are initially responsible for the increase in vent. 3-Breathing Rate:  Normally = 12-16bpm, up to 40-50 bpm  Responsible for the increase in minute ventilation that occur late in maximal exercise, esp. after AT reached

14. 4-Dead space/ Tidal volume Ratio:  Normally= 0.20-0.40, ↓ during exercise 0.04-0.20  ↓ significantly during exercise d.t ↑ in tidal volume with constant dead space 5-Pulmonary capillary blood transit time:  Normally= 0.75 second, ↓ 0.38 second d.t ↑ C.O.

15. 6-Alveolar-Arterial Oxygen Difference:  Normally= 10 mmHg changes little until a heavy workload is achieved. However, it can increase to 20-30 mmHg. 7-Oxygen Transport:  Local conditions of increased temp., PCO2 and a relative acidosis in the muscle tissues → greater release of oxygen by the blood for use by the tissues for metabolism.

16. 1-Cardiac Output:  Normally = 4-6L/min up to 20L/min  Increase linearly with increases in the workload during exercise till the point of exhaustion.  At work levels of up 50%of an individuals exercise capacity, the ↑ in C.O is d.t ↑ in heart rate and stroke volume together. After this point, it ll be d.t. in ↑ heart rate.

17. 2-Stroke Volume:  Normally = 50-80 ml can double during exercise.  Increase linearly with increase in workload until a maximum value is achieved, ≈ 50% of an individuals capacity for exercise.  After a HR of about 120bpm, there is little additional increase in SV → CO increase based in HR.

18. 3-Heart Rate:  Can increase as much as 2.5-4 times the resting HR.  HR max is achieved just prior of total exhaustion, considered as physiologic end point for each individual.  HRmax (±10bpm)= 210-(0.65X age)  HRmax (±10bpm)=220- age

19. 4-Oxygen pulse:  In order to meet the demands of increasing muscle work during exercise, each heart contraction must deliver a greater quantity of oxygen out to the body.  O2 pulse= VO2/HR  Normally = 2.5-4 ml o2/ heart beat up to 10-15 ml in exercise.

20. 5-Blood pressure:  During exercise →↑systolic blood pressure (up to 200mmHg) while diastolic blood pressure remains relatively stable( may ↑up to 90mmHg)  Pulse pressure (difference between systolic and diastolic pressure) ↑ during exercise. 6-Arterial- Venous Oxygen Content Difference:  During maximal exercise the difference ↑2.5-3 times the resting value. (N. 5 vol%)  The ↑ is due to the greater amounts of O2 that are extracted by the working muscle tissue during exercise.

21. 7-Distribution of circulation:  Circulation to the skeletal muscles increases which in turn increase the cardiac output.  Circulation to the heart ↑.  Skin perfusion ↑ as cooling mechanism for the body but can ↓ at extreme exercise levels (as the muscles demand ↑)

22. Thank you