In order to determine the ventilatory threshold (VT) and the lactate threshold (LT) in a reliable way, a new method is proposed and compared with conventional methods. The new method consists of calculating the point that yields the maximal distance from a curve representing ventilatory and metabolic variables as a function of oxygen uptake (VO2) to the line formed by the two end points of the curve (Dmax method). Male cyclists (n = 8) performed two incremental exercise tests a week apart. Ventilatory/metabolic variables were measured and blood was sampled for later lactate measurement during each workload and immediately after exercise. No statistical differences were observed in the threshold values (expressed as absolute oxygen uptake; VO2) determined by the Dmax method and the conventional linear regression method (according to O2 equivalent; EqO2) and venous blood at the onset of blood lactate (OBLA), while VT assessed with the conventional linear method (according to the slope of CO2 output; Vslope) yielded significantly lower threshold values. Similar results were obtained from the reproducibility test. Thus, the Dmax method appears to be an objective and reliable method for threshold determination, which can be applied to various ventilatory or metabolic variables yet yield similar results. The results also showed that breathing frequency can be used to determine VT.

A B S T R A C TThe aim of the present study was to establish whether gastro-intestinal (GI) complaints observed during and after ultra-endurance exercise are related to gut ischaemia-associated leakage of endotoxins [lipopolysaccharide (LPS)] into the circulation and associated cytokine production. Therefore we collected blood samples from 29 athletes before, immediately after, and 1, 2 and 16 h after a long-distance triathlon for measurement of LPS, tumour necrosis factor-α and interleukin-6 (IL-6). As the cytokine response would trigger an acute-phase response, characteristic variables of these responses were also measured, along with creatine kinase (CK) to obtain an indicator of muscle damage. There was a high incidence (93 % of all participants) of GI symptoms ; 45 % reported severe complaints and 7 % of the participants abandoned the race because of severe GI distress. Mild endotoxaemia (5-15 pg/ml) was evident in 68 % of the athletes immediately after the race, as also indicated by a reduction in IgG anti-LPS levels. In addition, we observed production of IL-6 (27-fold increase immediately after the race), leading to an acutephase response (20-fold increase in C-reactive protein and 12 % decrease in pre-albumin 16 h after the race). The extent of endotoxaemia was not correlated with the GI complaints or the IL-6 response, but did show a correlation with the elevation in C-reactive protein (r s 0.389 ; P l 0.037). Creatine kinase levels were increased significantly immediately post-race, and increased further in the follow-up period. Creatine kinase levels did not correlate with those of either IL-6 or C-reactive protein. It is therefore concluded that LPS does enter the circulation after ultra-endurance exercise and may, together with muscle damage, be responsible for the increased cytokine response and hence GI complaints in these athletes.

995.Accepted aftel revision: 0ctober 30, 1994 &t+J*$Bãi The effect of dlfferent dosa ges of caffelne (0 -5 -9 -13 mg 'l

Carbohydrate-electrolyte (CE) feedings have been shown to improve endurance performance at moderate intensities (60-75% VO2max) and or more than 2 h duration. The effects of CE feedings during high intensity exercise (i.e. > or = 80% VO2 max) of shorter duration (approximately 1 h) are less clear. Therefore the purpose of the present study was to investigate the effect of the ingestion of a 7.6% CE solution during exercise on time trial cycling performance of approximately 1 h. This type of performance testing has been shown to be more reproducible (coefficient of variation 3.35%) than the traditional exercise test to exhaustion. On two occasions and in random order nineteen endurance trained cyclists completed an exercise test requiring the accomplishment of a set amount of work as fast as possible (time trial) under strictly standardized conditions. As the start and during the trials they drank in total 14 ml/kg of either a 7.6% CE solution or artificially flavored and colored water (placebo). Time to complete the set amount of work was significantly reduced and thus performance was significantly increase (p < 0.001) with the CE drink by 2.3%. Time to complete the set amount of work was 58.74 +/- 0.52 min with CE and 60.15 +/- 0.65 min with placebo (p < 0.001). Average workload during the time trials was 297.5 +/- 1.4W and 291.0 +/- 10.3 W, respectively. Subjects exercised at 76.4 +/- 0.7% of their maximal work rate (Wmax) with CE and at 74.8% Wmax with placebo (p < 0.001). It was concluded tht also in relative short term (1h) high intensity (75% Wmax) cycling exercise ingestion of a carbohydrate-electrolyte solution compared to placebo improves performance.

[Aims] In the present study, we examined effects of exercise training (TR) on high fat diet (HFD)-induced expression changes of prothymosin α (ProTα) and its functions in white adipose tissue (WAT). [Methods] Eight-week-old male C57BL/6J mice were divided randomly into three groups: 1) C mice: control mice; 2) HFD mice: mice fed HFD (60% fat) for 4 months; 3) HFD-TR mice: mice fed HFD with voluntary TR on a running wheel for 4 months. We then investigated the expression of ProTα in WAT. Moreover, to investigate the function of ProTα in adipocytes, ProTα siRNA or recombinant lentivirus containing ProTα cDNA was infected into mouse 3T3-L1 adipocytes. [Results] Although the levels of body and WAT mass in HFD mice were significantly higher than those of C mice, TR inhibited such HFD-induced increases. Moreover, although expression of ProTα in WAT was upregulated by HFD, TR markedly attenuated HFD-induced expression of ProTα. The reduction of ProTα in 3T3-L1 cells resulted in inhibition of adipocyte differentiation with decreased expression of CCAAT-enhancer-binding proteinα (C/EBPα) gene. Conversely, overexpression of ProTα in 3T3-L1 cells enhanced expression of genes for C/EBPα and peroxi-some proliferator-activated receptor γ. [Conclusions] These results suggest that ProTα involves in adipocyte differentiation. Further, TR attenuates HFD-induced increases in expression of ProTα, which is speculated to be implicated in anti-obesity effects of TR. [Aims] Maximal fat oxidation (MFO) in the graded exercise test is considered to be an indicator of the capacity to oxidize fat during exercise. MFO varies widely based on cardiorespiratory fitness and body composition. Fat oxidation at rest (FO rest) positively correlated with MFO in overweight and healthy untrained people. However, it is unclear whether this positive correlation applies to all people with various levels of cardiorespiratory fitness and body composition. The current study examined the correlations between FO rest and MFO in trained, healthy inactive normal weight and overweight men. [Methods] This study included 8 trained, 6 healthy inactive normal weight, and 7 overweight men. All participants rested for 30 min in the supine position and performed a graded exercise test on a treadmill in the morning after a 12 h overnight fast. FO rest , maximal oxygen consumption (V ・ O 2 max), and MFO were measured by indirect calorimetry. Pearson's correlation coefficient was calculated between V ・ O 2 max and FO rest or MFO, FO rest and MFO. [Results] V ・ O 2 max significantly positively correlated with FO rest and MFO (R = 0.51, 0.72; P < 0.05, 0.01, respectively). FO rest significantly positively correlated with MFO (R = 0.71, P < 0.01). [Conclusions] FO rest positively correlated with MFO in trained, healthy inactive normal weight and overweight men. [Aims] Various clinical and epidemiological studies have shown an inverse association between serum high-density lipoprotein (HDL) cholesterol and cardiovascular events. Exercise is an effective treatment for increasin...