The relationships among four descriptors of lactate increase: lactate threshold (LT) (the VO2 at which blood lactate concentration begins to increase above the resting level during an incremental exercise test), LT1 (the VO2 at which blood lactate increases 1 mM above the resting level), LT2 (the VO2 at which blood lactate concentration reaches a fixed value of 2 mM), onset of blood lactate accumulation (OBLA; the VO2 at which blood lactate reaches a concentration of 4 mM), were compared with aerobic capacity (VO2max) and 12 min running performance in 19 untrained female students. The VO2 (+/- SD) of LT, LT1, LT2, OBLA, and VO2max were 14.5 +/- 3.7 ml X kg-1 X min-1, 22.5 +/- 4.3 ml X kg-1 X min-1, 22.2 +/- 4.5 ml X kg-1 X min-1, 30.3 +/- 5.2 ml X kg-1 X min-1 and 36.0 +/- 5.1 ml X kg-1 X min-1, respectively. The mean (+/- SD) distance covered in the 12 min running was 2356 +/- 160 m. The results were as follows: 1) the lactate parameters (i.e. LT, LT1, LT2, and OBLA) were highly correlated with each other. 2) all the lactate parameters were related to VO2max and endurance running performance with a high correlation coefficient. Of the four descriptors of lactate change with exercise, LT correlated best with VO2max and endurance running performance compared to LT1, LT2 and OBLA. It is concluded that lactate threshold is the best index for aerobic capacity and endurance running performance.

To assess the most important determinant for successful distance running (800 m, 1500 m and 3000 m events) in female athletes, measurements of several anaerobic indices were made (peak power, mean power) using the Wingate anaerobic test (WAnT), and aerobic indices such as oxygen uptake (VO2) or running velocity (v) at lactate threshold (LT), VO2 or v at onset of blood lactate accumulation (OBLA), running economy (RE), and maximal oxygen uptake were determined using the incremental treadmill test. The RE was represented by a VO2 value measured at 240 m.min-1 of a standard treadmill velocity. A stepwise multiple regression analysis (SAS stepwise procedure) combined the best features of forward inclusion and backward elimination to determine the most important factors in predicting the performance of running these distances as dependent variables. The stepwise procedure showed that the blood lactate variables such as LT and/or OBLA are highly correlated with, and contributed to predicting performance running 800 m-3000 m, whereas the anaerobic component was related only to running 800 m. In conclusion, blood lactate variables account for a large part of the variation in distance running performance in female as in male runners. The component of the anaerobic system which can be measured by the WAnT was shown to contribute to performance in running 800 m, but not in longer distances.

Objective In patients with chronic obstructive pulmonary disease (COPD), patient age and initial value of forced expiratory volume in 1 second (FEV1) have been considered the most accurate predictors of mortality among the parameters obtained from pulmonary exercise tests. However, few studies have examined the predictive variables of prognosis among exercise parameters in COPD. We therefore attempted to identify the best index for predicting long-term survival in patients with COPD among the cardiopulmonary variables obtained during exercise testing.Patients and Methods Fifty-eight patients with COPD (50 men and 8 women) without hypoxemia at rest or other serious complications performed resting pulmonary function tests followed by a symptom-limited ramp exercise test on a cycle ergometer with breath-by-breath gas analysis and arterial blood gas sampling.Results After 3,570±1,373 days follow-up (mean±SD), 21 died because of deaths by respiratory failure. The overall survival rates calculated by the Kaplan-Meier method were 92.9% and 75.8% at 5 years and 10 years, respectively. In univariate Cox hazards analysis, age, FEV1, VC, RV/TLC, V Emax, V O2 max, V CO2 max, PaO2 max, PaCO2max, and PaO2 at rest were found to be significant prognostic indices of survival. However, multivariate analysis revealed only FEV1, PaO2max, and age as independent predictors of mortality. In severe COPD patients (FEV1 <50% predicted, n=35), PaO2max and age also correlated with prognosis, whereas FEV1 did not.Conclusion Pulmonary exercise testing is useful in predicting prognosis in patients with COPD. (Internal Medicine 44: 20-25, 2005)

Cyclooxygenase-2 (COX-2) is an inducible cyclooxygenase enzyme and may play an important role in the pathogenesis of lung injury and in pulmonary vascular remodeling. In this study we determined the effects of acute or chronic hypoxia on COX-2 induction and its modulation by .NO and adenosine 3'-5'-cyclic monophosphate (cAMP). Isolated perfused rat lungs were exposed to a normoxic gas mixture or a hypoxic gas mixture for 3 h. Northern blot analysis showed that 3 h of acute hypoxia were sufficient to increase COX-2 but not COX-1 transcripts in the lung. COX-2 expression induced by acute hypoxia was enhanced by an inhibitor of nitric oxide synthase, N(G)-nitro-L-arginine methyl ester, and was suppressed by sodium nitroprusside, meclofenamate, and H-7 (an inhibitor of protein kinase A and C). COX-2 expression was also enhanced by dibutyryl cAMP and iloprost, a prostacyclin analogue. In contrast, 2 wk of chronic hypobaric hypoxia did not enhance COX-2 expression in the lung, but increased COX-2 protein levels, as assessed by Western blots. We conclude that acute hypoxia induces COX-2 gene expression in rat lung and that COX-2 induction by acute hypoxia is modulated by .NO, cAMP, and cyclooxygenase products. In particular, prostacyclin produced by the lung during hypoxia or shear stress induces lung COX-2 expression via a positive feedback mechanism.