Redox Status of Professional Soccer Players is Influenced by Training Load Throughout a Season.

The purpose of this study was to follow-up the variation of pro-/antioxidant status throughout a whole season in elite professional soccer players from the French league (n=19, 18.3±0.6 years) and to examine a possible link between these variations and training load. 5 time points (T1, T2, T3, T4, T5) were proposed to surround crucial periods of training during the whole season: the pre-season training/mid-season periods (T1-T2 and T3-T4), the championship or in-season periods (T2-T3 and T4-T5). At these times, blood samples were collected to measure pro-/antioxidant status (in erythrocytes: the ratio of reduced glutathione/oxidized glutathione, superoxide dismutase and glutathione peroxidase activities, in plasma: alpha-tocopherol, beta-carotene), and dietary intakes were also recorded. Training loads were quantified by the rating of perceived exertion method weekly throughout the season. Pro-/antioxidant-related measurements showed no modifications except for GSH/GSSG ratio, which evolved significantly between season periods: from 36.43±4.15 (T1) to 115.99±16.43 (T2) to 91.64±21.24 (T3) to 202.29±29.26 (T4) to 59.61±14.61 (T5). We observed a significant correlation (r(2)=0.84) between changes in GSH/GSSH ratio and cumulated mean training loads. In conclusion, these results suggest that the redox status of professional soccer players is altered according to training period (in-season periods) and that GSH/GSSH ratio variations are correlated with cumulated training loads.

Endurance training and insulin therapy need to be associated to fully exert their respective beneficial effects on oxidant stress and glycemic regulation in diabetic rats.

In type 1 diabetic subjects, hyperglycemia-induced oxidant stress (OS) plays a central role in the onset and development of diabetes complications. This study aimed to assess the benefits of an endurance training program and insulin therapy, alone or in combination, on the glycemic regulation, markers for OS, and antioxidant system in diabetic rats. Forty male Wistar rats were divided into diabetic (D), insulin-treated diabetic (D-Ins), diabetic trained (D-Tr), or insulin-treated diabetic trained (D-Ins+ Tr) groups. An additional healthy group served as control group. Insulin therapy (Lantus, insulin glargine, Sanofi) and endurance training (a treadmill run of 60 min/day, 25 m/min, 5 days/week) were initiated 1 week after streptozotocin-induced diabetes (45 mg/kg) and lasted for 8 weeks. At the end of the protocol, blood glucose and fructosamine levels, markers for skeletal muscle OS (CML, isoprostanes, GSH/GSSG) and antioxidant system (SOD and GPx activity, ORAC) were assessed. In diabetic rats, the glycemic control was altered and OS marker levels were increased, while the antioxidant system activity remained unchanged. Insulin treatment improved the glycemic regulation, the pro-antioxidant status, and contributed to the reduction of OS marker levels. Endurance training decreased OS marker levels without improving the antioxidant enzyme activity. Endurance training and insulin therapy acted independently (by different ways), but their association prolonged the insulin action and allowed a better adaptation of the antioxidant system. To conclude, our results demonstrate that combination of insulin treatment and endurance training leads to greater benefits on the glycemic regulation and oxidant status.

Superoxide production pathways in aortas of diabetic rats: beneficial effects of insulin therapy and endurance training.

Superoxide (O 2 (·-) ) overproduction, by decreasing the nitric oxide ((·)NO) bioavailability, contributes to vascular complications in type 1 diabetes. In this disease, the vascular O 2 (·-) can be produced by the NADPH oxidase (NOX), nitric oxide synthase (NOS), and xanthine oxidase (XO). This study aimed to determine the contribution of each enzymatic pathway in hyperglycemia-induced O 2 (·-) overproduction, and the effects of an endurance training program and insulin therapy, associated or not, on the O 2 (·-) production (amount and related enzymes) in diabetic rats. Forty male Wistar rats were divided into diabetic (D), diabetic treated with insulin (D-Ins), diabetic trained (D-Tr), or diabetic insulin-treated and trained (D-Ins + Tr) groups. An additional healthy group was used as control. Insulin therapy (Glargine Lantus, Sanofi) and endurance training (treadmill run: 60 min/day, 25 m/min, 5 days/week) started 1 week after diabetes induction by streptozotocin (45 mg/kg), and lasted for 8 weeks. At the end of the protocol, the O 2 (·-) production in aorta rings was evaluated by histochemical analyses (DHE staining). Each production pathway was studied by inhibiting NOX (apocynin), NOS (L-Name), or XO (allopurinol) before DHE staining. Diabetic rats exhibited hyperglycemia-induced O 2 (·-) overproduction, resulting from NOX, NOS, and XO activation. Insulin therapy and endurance training, associated or not, decreased efficiently and similarly the O 2 (·-) overproduction. Insulin therapy reduced the hyperglycemia and decreased the three enzymatic pathways implicated in the O 2 (·-) production. Endurance training decreased directly the NOS and XO activity. While both therapeutic strategies activated different pathways, their association did not reduce the O 2 (·-) overproduction more significantly.

Obesity and catecholamine responses to maximal exercise in adolescent girls.

The aim of this study was to investigate plasma catecholamine [adrenaline (A) and noradrenaline (NA)] concentrations at rest and in response to maximal exercise in three different groups of adolescent girls. According to their body mass index, 34 adolescent girls aged 15-16 years were divided into three groups: a normal weight group (NO) (n = 11), an overweight group (OW) (n = 11) and an obese group (OB) (n = 12). Plasma A and NA concentrations were measured at rest during fasting conditions (A(0) and NA(0)), after a standardized breakfast (A(rest) and NA(rest)) and immediately after an incremental exhaustive exercise (A(EX) and NA(EX)). A (0) and NA(0) were not significantly different among the three groups. However, the A(0)/NA(0) was statistically lower in OB compared to OW and NO. A(EX) and NA(EX) were significantly higher than resting values in the three groups. However, in response to exercise, no significant differences were reported between OB (A(EX) = 2.20 +/- 0.13 nmol/l, NA(EX) = 12.28 +/- 0.64 nmol/l), OW (A(EX) = 2.39 +/- 0.23 nmol/l, NA(EX) = 12.94 +/- 0.93 nmol/l) and NO (A(EX) = 2.52 +/- 0.24 nmol/l, NA(EX) = 12.60 +/- 0.63 nmol/l). In conclusion, our results showed that at rest, in adolescent girls, the responsiveness of the adrenal medulla to the sympathetic nervous activity is lower in OB subjects compared to OW and NO ones. However, in response to maximal exercise, plasma catecholamines are not affected by obesity.

Exercise-induced oxidative stress in overweight adolescent girls: roles of basal insulin resistance and inflammation and oxygen overconsumption.

HYPOTHESIS: Basal insulin resistance (IR) and inflammation exacerbate post-exercise oxidative stress (OS) in overweight adolescent girls. DESIGN: Cross-sectional study, effect of incremental ergocycle exercise until exhaustion on OS markers. PARTICIPANTS: Normal-weight (control) (n=17, body mass index (BMI): 20-24.2 kg/m(2)) and overweight adolescent girls (n=29, BMI: 24.1-36.6 kg/m(2)). MEASUREMENTS: Dietary measurement, physical activity assessment (validated questionnaires), fat distribution parameters (by dual-energy X-ray absorptiometry and anthropometry) and maximal oxygen consumption (VO2peak). Blood assays include the following: (1) at fasting state: blood cell count, lipid profile, and IR parameters (leptin/adiponectin ratio (L/A), homeostasis model assessment of IR, insulin/glucose ratio; (2) before exercise: inflammation and OS markers (interleukin-6 (IL-6), C-reactive protein (CRP), myeloperoxidase (MPO), reduced glutathione/oxidized glutathione ratio (GSH/GSSG), 15 F(2)alpha-isoprostanes (F(2)-Isop), lipid hydroperoxides (ROOH), oxidized low-density lipoprotein (ox-LDL)) and antioxidant status (superoxide dismutase (SOD), glutathione peroxidase (GPX), vitamin C, alpha-tocopherol and beta-carotene); and (3) after exercise: inflammation and OS markers. RESULTS: At rest, overweight girls had a deteriorated lipid profile and significantly higher values of IR parameters and inflammation markers, compared with the control girls. These alterations were associated with a moderate rest OS state (lower GSH/GSSG ratio, alpha-tocopherol/total cholesterol (TC) ratio and GPX activity). In absolute values, overweight girls exhibited higher peak power output and oxygen consumption (VO2peak), compared with the control girls. Exercise exacerbated OS only in the overweight group (significant increase in F(2)-Isop, ROOH and MPO). As hypothesized, basal IR and inflammation state were correlated with the post-exercise OS. However, the adjustment of F(2)-Isop, ROOH and MPO variation per exercise VO(2) variation canceled the intergroup differences. CONCLUSION: In overweight adolescent girls, the main factors of OS, after incremental exhaustive exercise, are not the basal IR and inflammation states, but oxygen overconsumption.

Athletic performance and weight changes during the "Marathon of Sands" in athletes well-trained in endurance.

The purpose of this study is to examine the effects of the "Marathon of Sands" (MS), a 7-day, self-sufficient-diet, multi-stage running race across a section of the Moroccan desert, on body weight and plasma volume variation (PVV) and the relationship of these factors to performance in athletes who are well-trained in endurance. Sixteen MS runners agreed to participate in this study. Weight and body composition were measured and venous blood samples were taken before the first stage (D0), after the third stage (D3) and at the end of the MS (after the sixth stage: D6). Haematocrit and haemoglobin were used to calculate PVV at (D0, D3, and D6). No significant plasma volume decrease was observed throughout the race. Significant decreases in total body weight (BW), fat-free mass (FFM) and fat mass (FM) were observed in D3 and D6 (-4.3%, -3.5%, -0.8%; and -6.1%, -5%, -1.1%, respectively, for BW, FFM and FM at D3 and D6). This study clearly shows that, despite extreme conditions, the MS did not lead to a significant PV decrease in athletes well-trained in endurance. This study also supports the hypothesis that significant body weight loss may not systematically affect performances during long duration multiple-stage races.

Comparison of total antioxidant capacity of salivary, capillary and venous samplings: interest of the salivary total antioxidant capacity on triathletes during training season.

AIM: Total antioxidant capacity (TAC) is an essential parameter to watch over defense system of athletes exposed to an oxidant stress during intensive periods of training. To control this parameter throughout the training period, repetitive biological samples are required. The TAC is usually investigated in venous blood which needs invasive withdrawings. Thus, we proposed to find alternatives to venous blood analysis by venepuncture, which is invasive, stressful and not allow a regular follow-up on athletes during annual training season. METHODS: We measured capillary and salivary TAC in 65 physically active subjects at rest and compared them to the venous TAC. We followed the evolution of venous and salivary TAC in 7 triathletes throughout an annual training period (March and June) corresponding to two different types of training. RESULTS: There was a good correlation between plasma venous and capillary TAC values (r=0.77; P<0.0001), but salivary TAC were significantly lower than the plasma ones and did not correlate. Venous and saliva TAC of triathletes were significantly higher in March compared to June. The variations of plasma and salivary TAC between the two periods of training were correlated (r=0.96; P<0.01). CONCLUSION: The capillary sampling can replace the venous one for TAC evaluation in routine assays for the follow-up of athletes. Even if saliva TAC did not reflect plasma TAC, it could be used in the follow-up of athletes since a strong correlation is found between the variation of saliva and plasma TAC during the training season.

Changes in blood lipid peroxidation markers and antioxidants after a single sprint anaerobic exercise.

It has been well demonstrated that the principal factor responsible for oxidative damage during exercise is the increase in oxygen consumption. However, other theoretical factors (acidosis, catecholamine autoxidation, ischemia-reperfusion syndrome, etc.) that are known to induce, in vitro, oxidative damage may also be operative during short-term supramaximal anaerobic exercise. Therefore, we hypothesized that short-term supramaximal anaerobic exercise (30-s Wingate test) could induce an oxidative stress. Lipid peroxidation markers [serum lipid radical production detected by electron spin resonance (ESR) spectroscopy and plasma malondialdehyde (MDA) levels detected by the thiobarbituric acid reactive substances (TBARS) method], as well as erythrocyte antioxidant enzyme activities [glutathione peroxidase (GPx), superoxide dismutase (SOD)] and erythrocyte glutathione (GSH) levels, were measured at rest, after the Wingate test and during the 40 min of recovery. The recovery of exercise was associated with a significant increase (x2.7) in lipid radical production detected by ESR spectroscopy, as well as with changes in the erythrocyte GSH level (-13.6%) and SOD activity (-11.7%). The paradoxical decrease in plasma TBARS (-23.7%) which was correlated with the peak power developed during the Wingate test ( r=-0.7), strongly suggests that such exercise stimulates the elimination of MDA. In conclusion, this study demonstrates that short-term supramaximal anaerobic exercise induces an oxidative stress and that the plasma TBARS level is not a suitable marker during this type of exercise.

Free radical scavenging and antioxidant effects of lactate ion: an in vitro study.

Divergent literature data are found concerning the effect of lactate on free radical production during exercise. To clarify this point, we tested the pro- or antioxidant effect of lactate ion in vitro at different concentrations using three methods: 1) electron paramagnetic resonance (EPR) was used to study the scavenging ability of lactate toward the superoxide aion (O(2)(-).) and hydroxyl radical (.OH); 2) linoleic acid micelles were employed to investigate the lipid radical scavenging capacity of lactate; and 3) primary rat hepatocyte culture was used to study the inhibition of membrane lipid peroxidation by lactate. EPR experiments exhibited scavenging activities of lactate toward both O(2)(-). and.OH; lactate was also able to inhibit lipid peroxidation of hepatocyte culture. Both effects of lactate were concentration dependent. However, no inhibition of lipid peroxidation by lactate was observed in the micelle model. These results suggested that lactate ion may prevent lipid peroxidation by scavenging free radicals such as O(2)(-). and.OH but not lipid radicals. Thus lactate ion might be considered as a potential antioxidant agent.