Long-distance running is an exhausting effort for the whole organism. Prolonged aerobic exercise induces changes in inflammatory markers. However, predicting muscle damage in response has limitations in terms of selecting biomarkers used to measure inflammatory status. The present study conducts a systematic review and meta-analysis of articles focusing in ultra-marathon, marathon, and half-marathon and levels of cytokines. The search was conducted in PubMed, Web of Science, and Scopus databases, resulting in the inclusion of 76 articles. IL-6 was highlighted, evaluated in 62 studies and show increase in the standard mean difference (SMD): half-marathon (SMD −1.36; IC 95%: −1.82, −0.89, Ch2:0.58; tau2:0.00; p < 0.0001), marathon (SMD −6.81; IC 95%: −9.26, −4.37; Ch2:481.37 tau2:11.88; p < 0.0001) and ultra-marathon (SMD −8.00 IC 95%: −10.47, −5.53; Ch2:328.40; tau2:14.19; p < 0.0001). In contrast meta-regression analysis did not show relationship to the running distance (p = 0.864). The meta-analysis evidenced increase in the concentration of IL-1ra (p < 0.0001), IL-1B (p < 0.0001), IL-8 (p < 0.0001), IL-10 (p < 0.0001) and TNF-α (p < 0.0001). Reduction in IL-2 (p < 0.0001) and INF-y (p < 0.03) and no change in the IL-4 (p < 0.56). The number of studies evaluating the effect of adipokines was limited, however Leptin and Resistin were recurrent. The effects of an acute bout of prolonged aerobic exercise will protect against chronic systemic inflammation. The time to return to baseline values showed a substantial and dose-dependent relationship with run volume. The concentration of IL-6 was robustly studied and the marathon running was the most explored. Network of endocrine interactions in which circulating factors, released in extreme exercises, interplay through inter-organ crosstalk and physiologic changes were expressed. The running volume variability was able to modulate compounds that play a fundamental role in the maintenance of homeostasis and cell signaling.

Ultra-endurance (UE) race has been associated with brain metabolic changes, but it is still unknown which regions are vulnerable. This study investigated whether high-volume training in rodents, even under moderate intensity, can induce cerebellar oxidative and inflammatory status. Forty-five adult rats were divided into six groups according to a training period, followed or not by an exhaustion test (ET) that simulated UE: control (C), control + ET (C-ET), moderate-volume (MV) training and MV-ET, high-volume training (HV) and HV-ET. The training period was 30 (MV) and 90 (HV) min/day, 5 times/week for 3 months as a continuous running on a treadmill at a maximum velocity of 12 m/min. After 24 h, the ET was performed at 50% maximum velocities up to the animals refused to run, and then serum lactate levels were evaluated. Serum and cerebellar homogenates were obtained 24 h after ET. Serum creatine kinase (CK), lactate dehydrogenase (LDH), and corticosterone levels were assessed. Lipid peroxidation (LP), nitric oxide (NO), Interleukin 1β (IL-1β), and GFAP proteins, reduced and oxidized glutathione (GSH and GSSG) levels, superoxide dismutase (SOD) and catalase (CAT) activities were quantified in the cerebellum. Serum lactate concentrations were lower in MV-ET (∼20%) and HV-ET (∼40%) compared to the C-ET group. CK and corticosterone levels were increased more than ∼ twofold by HV training compared to control. ET increased CK levels in MV-ET vs. MV group ( P = 0.026). HV induced higher LP levels (∼40%), but an additive effect of ET was only seen in the MV-ET group ( P = 0.02). SOD activity was higher in all trained groups vs. C and C-ET ( P < 0.05). CAT activity, however, was intensified only in the MV group ( P < 0.02). The 50 kDa GFAP levels were enhanced in C-ET and MV-ET vs. respective controls, while 42 kDa (∼40%) and 39 kDa (∼26%) isoform levels were reduced. In the HV-ET group, the 50 KDa isoform amount was reduced ∼40–60% compared to the other groups and the 39 KDa isoform, increased sevenfold. LDH levels, GSH/GSSG ratio, and NO production were not modified. ET elevated IL-1β levels in the CT and MV groups. Data shows that cerebellar resilience to oxidative damage may be maintained under moderate-volume training, but it is reduced by UE running. High-volume training per se provoked systemic metabolic changes, cerebellar lipid peroxidation, and unbalanced enzymatic antioxidant resource. UE after high-volume training modified the GFAP isoform profile suggesting impaired astrocyte reactivity in the cerebellum.

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Background. Hyperglycemia reduces tendon homeostasis. Effects of physical exercise on diabetic rats have been widely studied; however, the effects of a combined physical and insulin therapy on biomechanical properties of the Achilles tendon (AT) remain unclear. Therefore, the objective of this study was to evaluate the effects of the combination of moderate-intensity exercise on a treadmill and insulin therapy on metabolism, physical conditioning, and biomechanics of AT in diabetic rats. Methods. Forty-eight Wistar rats were divided into six groups: Sedentary Control-SCG, Treadmill Control-TCG, Sedentary Diabetic-SDG, Sedentary Insulin Diabetic-SIDG, Treadmill Diabetic-TDG, and Treadmill Insulin Diabetic-TIDG. Diabetic animals were induced with streptozotocin diluted in sodium citrate buffer (50 mg/Kg; 10 mM; pH 4.5; intraperitoneally). All groups were subjected to the maximal effort test for pre (MET 1 ) and post (MET 2 ) maximal speed determination. The exercise protocol was administered for 5 weeks (1 h/day, 5 days/week). Blood glucose levels and biomechanical properties of AT (e.g., traction) were evaluated. Results. Increased glycemia was observed in SDG (p<0.001; p=0.003), SIDG (p=0.009; p=0.037), and TDG (p=0.002; p=0.009); however, compared with SCG and TCG, TIDG showed no significant differences. Maximal force was reduced in TIDG (p=0.009) and SIDG (p = 0.002) and increased in SCG and TDG compared with in SIDG (p=0.024). The elastic modulus was reduced in TCG compared with in SCG (p = 0.011) and increased in SDG (p<0.001), SIDG (p=0.019), and TDG (p=0.006) compared with in TCG. Conclusions. The combined physical exercise and insulin therapy favors the stabilization of glycemic metabolic parameters and avoids increased tendon rigidity in diabetic rats.

The objective of this study was to analyze the acute effect of hyperoxia during the maximal treadmill test (MTT) of runners. Participants included 10 female street runners who performed the MTT under two different conditions: hyperoxia (HYPX), inhaling oxygen (60% O2) every 3 min; and normoxia (NORM), without additional oxygen inhalation. Both groups performed the MTT with increases in the slope of the run every 3 min until voluntary exhaustion. The variables of lactate concentration, the onset of blood lactate accumulation (OBLA), peripheral oxygen saturation (SpO2), heart rate (HR), and Borg scale were evaluated. It was verified after the comparison (HYPX vs. NORM) that stage 3 (p = 0.012, Cohen’s d = 1.76) and stage 4 (p < 0.001; Cohen’s d = 5.69) showed a reduction in lactate under the HYPX condition. OBLA under the HYPX condition was identified at a later stage than NORM. There were no differences in Borg scale, SpO2, and HR between the different conditions. It was concluded that the HYPX condition contributed to a reduction in lactate concentration and delayed OBLA in runners.