دورية
Factors which alter the relationship between ventilation and carbon dioxide production during exercise in normal subjects
| العنوان: | Factors which alter the relationship between ventilation and carbon dioxide production during exercise in normal subjects |
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| المؤلفون: | Clark, Andrew L., Volterrani, Maurizio, Piepoli, M., Coats, Andrew J.S. |
| المصدر: | European Journal of Applied Physiology; April 1996, Vol. 73 Issue: 1-2 p144-148, 5p |
| مستخلص: | The slope of the linear relationship between ventilation $$\left( {\dot V_{\text{E}} } \right)$$ and carbon dioxide production $$\left( {\dot V{\text{CO}}_{\text{2}} } \right)$$ has been thought to indicate that $$\dot V{\text{CO}}_{\text{2}} $$ is one of the major stimuli to $$\left( {\dot V_{\text{E}} } \right)$$ . A group of 15 normal subjects undertook different incremental treadmill exercise protocols to explore the relationship between $$\left( {\dot V_{\text{E}} } \right)$$ and $$\dot V{\text{CO}}_{\text{2}} $$ . An incremental protocol using 1 instead of 3-min stages of exercise resulted in an increase in the $$\dot V_{\text{E}} $$ to $$\dot V{\text{CO}}_{\text{2}} $$ ratio [26.84 (SEM 1.23) vs 31.08 (SEM 1.36) (P < 0.008) for the first stage, 25.24 (SEM 0.86) vs 27.83 (SEM 0.91) (P < 0.005) for the second stage and 23.90 (SEM 0.86) vs 26.34 (SEM 0.81) (P = 0.001) for the third stage]. Voluntary hyperventilation to double the control level of $$\dot V_{\text{E}} $$ during exercise resulted in an increase in the $$\dot V_{\text{E}} $$ to $$\dot V{\text{CO}}_{\text{2}} $$ slope [from 21.3 (SEM 0.71) for the control run to 35.1 (SEM 1.2) for the hyperventilation run (P < 0.001)]. Prolonged hyperventilation (5 min) during exercise at stage 2 of the Bruce protocol resulted in a continuted elevation of $$\dot V{\text{CO}}_{\text{2}} $$ and the $${{\dot V_{\text{E}} } \mathord{\left/ {\vphantom {{\dot V_{\text{E}} } {\dot V{\text{CO}}_{\text{2}} }}} \right. \kern-\nulldelimiterspace} {\dot V{\text{CO}}_{\text{2}} }}$$ slope. A steady state of $$\dot V_{\text{E}} $$ and metabolic gas exchange can only be said to have been present after at least 3 min of exercise. Voluntary hyperventilation increased the slope of the relationship between $$\dot V_{\text{E}} $$ and $$\dot V{\text{CO}}_{\text{2}} $$ . End-tidal carbon dioxide fell, but remained within the normal range. These results would suggest that a non-carbon dioxide factor may have been responsible for the increase we found in $$\dot V_{\text{E}} $$ during exercise, and that factors other than increased dead space ventilation can cause an increased ventilation to $$\dot V{\text{CO}}_{\text{2}} $$ slope, such as that seen in some pathophysiological conditions, such as chronic heart failure. |
| قاعدة البيانات: | Supplemental Index |
| تدمد: | 14396319 14396327 |
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| DOI: | 10.1007/BF00262823 |