Internationale Zeitschrift für Physikalische Medizin und Rehabilitation

Internationale Zeitschrift für Physikalische Medizin und Rehabilitation
Offener Zugang

ISSN: 2329-9096


Verification of Blood Lactate during Incremental Exercise Testing

Kazuyuki Kominami*, Masatoshi Akino

Background:The increase in Blood Lactate (BLa) level during incremental exercise testing (Inc-Ex) leads to bicarbonate ion buffering and excretion of carbon dioxide (CO2). The relationship between the excretion of excess CO2 and BLa during Inc-Ex is unclear. This study aimed to verify whether BLa could be estimated from excess CO2 excretion during Inc-Ex.

Methods: We recruited 11 patients (group P, age: 72.6 ± 8.5 years; male: 9) who were prescribed medication for cardiovascular risk factors or diseases. Twenty-two healthy participants (group H, age: 69.3 ± 6.7 years; male: 9) were also recruited for comparison. All participants performed the symptomatic limited cardiopulmonary exercise test, and their BLa levels were measured. Excess CO2 (the difference between oxygen uptake and CO2 excretion) was determined from breath-by-breath gas analysis data. BLa level was measured from arterialized fingertips every minute during Inc-Ex (10 W/min ramp exercise). Plots of per-minute excess CO2 and BLa were linearly regressed, and regression equations and coefficients were calculated along with 95% confidence intervals and prediction intervals.

Results: BLa levels were measured 9.2 ± 2.4 times per participant during Inc-Ex. BLa was significantly correlated with excess CO2 in both groups H and P (all participants: r=0.862, p<0.001, y=0.0139x+1.7364; group H: r=0.872, p<0.001, y=0.0108x+1.617; and group P: r=0.878, p<0.001, y=0.0139x+1.7364).

Conclusion: Excess CO2 aided in verifying BLa levels within a certain range. Excess CO2 during the cardiopulmonary exercise test is useful for estimating BLa levels.