Continuous Estimation of CO₂ Production during Exercise

Abstract.

A new method was developed for continuous isotopic estimation of human whole body CO₂ rate of appearance (Ra) during non-steady state exercise. The technique consisted of a breath-by-breath measurement of ¹³CO₂ enrichment (E) and a real-time fuzzy logic feedback system which controlled NaH¹³CO₃ infusion rate to achieve an isotopic steady state. Ra was estimated from the isotope infusion rate and body ¹³CO₂ enrichment which was equal to E at the isotopic steady state. During a non-steady state incremental cycle exercise (5 w/min or 10 w/min), NaH¹³CO₃ infusion rate was successfully increased by the action of feedback controller so as to keep E constant.

Keywords:

NaH¹³CO₃ - Fuzzy Logic Controller

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