Antioxidant defence and inflammatory response in professional road cyclists during a 4-day competition

Effects of Native Whey Protein and Carbohydrate Supplement on Physical Performance and Plasma Markers of Muscle Damage and Inflammation during a Simulated Rugby Sevens Tournament: A Double-Blind, Randomized, Placebo-Controlled, Crossover Study

The importance of optimized recovery during a sport competition is undisputed. The objective of this study was to determine the effects of recovery drinks comprising either carbohydrate only, or a mix of native whey proteins and carbohydrate to maintain physical performance and minimize muscle damage during a simulated rugby sevens (rugby 7s) tournament. Twelve well-trained male rugby players participated in three simulated rugby 7s tournament days with a week's interval in between. Each tournament comprised a sequence of three simulated matches, interspersed with 2 h of recovery. Three different recovery drinks were tested: a placebo (PLA, nonenergetic chocolate-flavored drink), a carbohydrate drink (CHO, 80 g of carbohydrate) or an isoenergetic carbohydrate-protein drink (P-CHO, 20 g of Pronativ^®, native whey protein and 60 g of carbohydrate). A different recovery drink, consumed after each match, was tested during each simulated tournament. Physical performance, muscle damage and muscle pain were assessed before and after each simulated tournament. Regarding physical performance, both P-CHO and CHO drinks had a positive effect on the maintenance of 50 m sprint time compared to the PLA drink (effect sizes large and moderate, respectively). Regarding muscle damage, the P-CHO supplement attenuated the creatine phosphokinase increase at POST6 compared to PLA (effect size, moderate). Finally, P-CHO and CHO drinks reduced the exercise-induced DOMS (effect size, moderate), compared to the PLA condition (effect size, large), while P-CHO only reduced pain on muscle palpation and pain when descending stairs compared to PLA 24 h post-tournament (effect size, small). This study suggests that consuming a recovery drink containing native whey proteins and carbohydrate or carbohydrate only after each match of a rugby 7s tournament may attenuate the exercise-induced increase in markers of muscle damage and maintain physical performance.

Melatonin Inhibits hIAPP Oligomerization by Preventing β-Sheet and Hydrogen Bond Formation of the Amyloidogenic Region Revealed by Replica-Exchange Molecular Dynamics Simulation

The pathogenesis of type 2 diabetes (T2D) is highly related to the abnormal self-assembly of the human islet amyloid polypeptide (hIAPP) into amyloid aggregates. To inhibit hIAPP aggregation is considered a promising therapeutic strategy for T2D treatment. Melatonin (Mel) was reported to effectively impede the accumulation of hIAPP aggregates and dissolve preformed fibrils. However, the underlying mechanism at the atomic level remains elusive. Here, we performed replica-exchange molecular dynamics (REMD) simulations to investigate the inhibitory effect of Mel on hIAPP oligomerization by using hIAPP20–29 octamer as templates. The conformational ensemble shows that Mel molecules can significantly prevent the β-sheet and backbone hydrogen bond formation of hIAPP20–29 octamer and remodel hIAPP oligomers and transform them into less compact conformations with more disordered contents. The interaction analysis shows that the binding behavior of Mel is dominated by hydrogen bonding with a peptide backbone and strengthened by aromatic stacking and CH–π interactions with peptide sidechains. The strong hIAPP–Mel interaction disrupts the hIAPP20–29 association, which is supposed to inhibit amyloid aggregation and cytotoxicity. We also performed conventional MD simulations to investigate the influence and binding affinity of Mel on the preformed hIAPP1–37 fibrillar octamer. Mel was found to preferentially bind to the amyloidogenic region hIAPP20–29, whereas it has a slight influence on the structural stability of the preformed fibrils. Our findings illustrate a possible pathway by which Mel alleviates diabetes symptoms from the perspective of Mel inhibiting amyloid deposits. This work reveals the inhibitory mechanism of Mel against hIAPP20–29 oligomerization, which provides useful clues for the development of efficient anti-amyloid agents.

Mechanisms of melatonin binding and destabilizing the protofilament and filament of tau R3-R4 domains revealed by molecular dynamics simulation

The accumulation of β-amyloid (Aβ) and tau protein is considered to be an important pathological characteristic of Alzheimer's disease (AD). Failure of medicine targeting Aβ has drawn more attention to the influence of tau protein and its fibrillization on neurodegeneration. Increasing evidence shows that melatonin (Mel) can effectively inhibit the formation of tau fibrils and disassemble preformed tau fibrils. However, the underlying mechanism is poorly understood. In this work, we investigated the kinetics of melatonin binding and destabilizing the tetrameric protofilament and octameric filament of tau R3-R4 domains by performing microsecond all-atom molecular dynamics simulations. Our results show that Mel is able to disrupt the C-shaped structure of the tau protofilament and filament, and destabilizes the association between N- and C-termini. Mel predominantly binds to β1 and β6-β8 regions and favors contact with the elongation surface, which is dominantly driven by hydrogen bonding interactions and facilitated by other interactions. The strong π-π stacking interaction of Mel with Y310 impedes the intramolecular CH-π interaction between I308 and Y310, and the cation-π interaction of Mel with R379 interferes with the formation of the D348-R379 salt bridge. Moreover, Mel occupies the protofilament surface in the tetrameric protofilament and prevents the formation of intermolecular hydrogen bonds between residues K331 and Q336 in the octameric filament. Our work provides molecular insights into Mel hindering tau fibrillization or destabilizing the protofilament and filament, and the revealed inhibitory mechanisms provide useful clues for the design of efficient anti-amyloid agents.

Exercise-induced oxidative stress and melatonin supplementation: current evidence

Melatonin possesses the indoleamine structure and exerts antioxidant and anti-inflammatory actions and other physiological properties. Physical exercise can influence secretion of melatonin. Melatonin is used as a natural supplement among athletes to regulate sleep cycles and protect muscles against oxidative damage. Despite decades of research, there is still a lack of a comprehensive and critical review on melatonin supplementation and physical activity relationship. The aim of this literature review is to examine the antioxidant, anti-inflammatory and other biological functions played by melatonin with reference to the effect of physical exercise on melatonin secretion and the effect of this compound supplementation on exercise-induced oxidative stress in athletes. Evidence shows that intense exercises disturb antioxidant status of competitive athletes, whereas supplementation with melatonin strengthens antioxidant status in trained athletes in various sports as the compound showed high potency in reduction of the oxidative stress and inflammation markers generated during intense and prolonged exercise.

Differences between Professional and Amateur Cyclists in Endogenous Antioxidant System Profile

Currently, no studies have examined the differences in endogenous antioxidant enzymes in professional and amateur cyclists and how these can influence sports performance. The aim of this study was to identify differences in endogenous antioxidants enzymes and hemogram between competitive levels of cycling and to see if differences found in these parameters could explain differences in performance. A comparative trial was carried out with 11 professional (PRO) and 15 amateur (AMA) cyclists. All cyclists performed an endogenous antioxidants analysis in the fasted state (visit 1) and an incremental test until exhaustion (visit 2). Higher values in catalase (CAT), oxidized glutathione (GSSG) and GSSG/GSH ratio and lower values in superoxide dismutase (SOD) were found in PRO compared to AMA (p < 0.05). Furthermore, an inverse correlation was found between power produced at ventilation thresholds 1 and 2 and GSSG/GSH (r = −0.657 and r = −0.635; p < 0.05, respectively) in PRO. Therefore, there is no well-defined endogenous antioxidant enzyme profile between the two competitive levels of cyclists. However, there was a relationship between GSSG/GSH ratio levels and moderate and submaximal exercise performance in the PRO cohort.

Inflammation, Peripheral Signals and Redox Homeostasis in Athletes Who Practice Different Sports

The importance of training in regulating body mass and performance is well known. Physical training induces metabolic changes in the organism, leading to the activation of adaptive mechanisms aimed at establishing a new dynamic equilibrium. However, exercise can have both positive and negative effects on inflammatory and redox statuses. In recent years, attention has focused on the regulation of energy homeostasis and most studies have reported the involvement of peripheral signals in influencing energy and even inflammatory homeostasis due to overtraining syndrome. Among these, leptin, adiponectin, ghrelin, interleukin-6 (IL6), interleukin-1β (IL1β) and tumour necrosis factor a (TNFa) were reported to influence energy and even inflammatory homeostasis. However, most studies were performed on sedentary individuals undergoing an aerobic training program. Therefore, the purpose of this review was to focus on high-performance exercise studies performed in athletes to correlate peripheral mediators and key inflammation markers with physiological and pathological conditions in different sports such as basketball, soccer, swimming and cycling.

Glycolytic Proteins Interact With Intracellular Melatonin in Saccharomyces cerevisiae

Melatonin is a bioactive compound that is present in fermented beverages and synthesized by yeast during alcoholic fermentation. Many studies have shown that melatonin interacts with some mammalian proteins, such as sirtuins or orphan receptor family proteins. The aim of this study was to determine the intracellular synthesis profile of melatonin in Saccharomyces cerevisiae and to identify the proteins that may interact with this molecule in yeast cells. Melatonin from fermentation samples was analyzed by liquid chromatography mass spectrometry, and proteins bound to melatonin were immunopurified by melatonin-IgG-Dynabeads. Melatonin was produced intracellularly in the lag phase of yeast growth and was exported to the extracellular media during the stationary phase. During this period, melatonin was bound to six proteins with molecular weights from 55 to 35 kDa. Sequence analysis showed that most proteins shared high levels of homology with glycolytic enzymes. An RNA-binding protein was also identified, the elongation alpha factor, which is related to mitochondria. This study reports for the first time the interaction of melatonin and proteins inside yeast cells. These results highlight the possible role of melatonin as a signal molecule and provide a new perspective for understanding its role in yeast.

The benefit of a supplement with the antioxidant melatonin on redox status and muscle damage in resistance-trained athletes

Previous data showed that the administration of high doses of melatonin improved the circadian system in athletes. Here, we investigated in the same experimental paradigm whether the antioxidant properties of melatonin has also beneficial effects against exercise-induced oxidative stress and muscle damage in athletes. Twenty-four athletes were treated with 100 mg·day−1 of melatonin or placebo 30 min before bedtime during 4 weeks in a randomized double-blind scheme. Exercise intensity was higher during the study that before starting it. Blood samples were collected before and after treatment, and plasma was used for oxygen radical absorption capacity (ORAC), lipid peroxidation (LPO), nitrite plus nitrate (NOx), and advanced oxidation protein products (AOPP) determinations. Glutathione (GSH), glutathione disulphide (GSSG) levels, and glutathione peroxidase (GPx) and reductase (GRd) activities, were measured in erythrocytes. Melatonin intake increased ORAC, reduced LPO and NOx levels, and prevented the increase of AOPP, compared to placebo group. Melatonin was also more efficient than placebo in reducing GSSG·GSH−1 and GPx·GRd−1 ratios. Melatonin, but not placebo, reduced creatine kinase, lactate dehydrogenase, creatinine, and total cholesterol levels. Overall, the data reflect a beneficial effect of melatonin treatment in resistance-training athletes, preventing extra- and intracellular oxidative stress induced by exercise, and yielding further skeletal muscle protection against exercise-induced oxidative damage.

Effects of acute physical exercise on oxidative stress and inflammatory status in young, sedentary obese subjects

Circulating oxidative stress and pro-inflammatory markers change after regular physical exercise; however, how a short session of acute physical activity affects the inflammatory status and redox balance in sedentary individuals is still unclear. Aim of this study is to assess antioxidant and inflammatory parameters, both at rest and after acute exercise, in sedentary young men with or without obesity. Thirty sedentary male volunteers, aged 20–45 (mean age 32 ± 7 years), were recruited, divided into 3 groups (normal weight: BMI < 25 kg/m²; overweight to moderate obesity: 25–35 kg/m²; severe obesity: 35–40 kg/m²), and their blood samples collected before and after a 20-min run at ~ 70% of their VO_2max for the measurement of Glutathione Reductase, Glutathione Peroxidase, Superoxide Dismutase, Total Antioxidant Status (TAS) and cytokines (IL-2, IL-4, IL-6, IL-8, IL-10, IL-1α, IL-1β, TNFα, MCP-1, VEGF, IFNγ, EGF). Inter-group comparisons demonstrated significantly higher Glutathione Reductase activity in severely obese subjects in the post-exercise period (P = 0.036), and higher EGF levels in normal weight individuals, either before (P = 0.003) and after exercise (P = 0.05). Intra-group comparisons showed that the acute exercise stress induced a significant increase in Glutathione Reductase activity in severely obese subjects only (P = 0.007), a significant decrease in MCP-1 in the normal weight group (P = 0.02), and a decrease in EGF levels in all groups (normal weight: P = 0.025, overweight/moderate obesity: P = 0.04, severe obesity: P = 0.018). Altogether, these findings suggest that in sedentary individuals with different ranges of BMI, Glutathione Reductase and distinct cytokines are differentially involved into the adaptive metabolic changes and redox responses induced by physical exercise. Therefore, these biomarkers may have the potential to identify individuals at higher risk for developing diseases pathophysiologically linked to oxidative stress.

Growth Hormone (GH) and Rehabilitation Promoted Distal Innervation in a Child Affected by Caudal Regression Syndrome

Caudal regression syndrome (CRS) is a malformation occurring during the fetal period and mainly characterized by an incomplete development of the spinal cord (SC), which is often accompanied by other developmental anomalies. We studied a 9-month old child with CRS who presented interruption of the SC at the L2–L3 level, sacral agenesis, a lack of innervation of the inferior limbs (flaccid paraplegia), and neurogenic bladder and bowel. Given the known positive effects of growth hormone (GH) on neural stem cells (NSCs), we treated him with GH and rehabilitation, trying to induce recovery from the aforementioned sequelae. The Gross Motor Function Test (GMFM)-88 test score was 12.31%. After a blood analysis, GH treatment (0.3 mg/day, 5 days/week, during 3 months and then 15 days without GH) and rehabilitation commenced. This protocol was followed for 5 years, the last GH dose being 1 mg/day. Blood analysis and physical exams were performed every 3 months initially and then every 6 months. Six months after commencing the treatment the GMFM-88 score increased to 39.48%. Responses to sensitive stimuli appeared in most of the territories explored; 18 months later sensitive innervation was complete and the patient moved all muscles over the knees and controlled his sphincters. Three years later he began to walk with crutches, there was plantar flexion, and the GMFM-88 score was 78.48%. In summary, GH plus rehabilitation may be useful for innervating distal areas below the level of the incomplete spinal cord in CRS. It is likely that GH acted on the ependymal SC NSCs, as the hormone does in the neurogenic niches of the brain, and rehabilitation helped to achieve practically full functionality.

The benefits of four weeks of melatonin treatment on circadian patterns in resistance-trained athletes

Exercise can induce circadian phase shifts depending on the duration, intensity and frequency. These modifications are of special meaning in athletes during training and competition. Melatonin, which is produced by the pineal gland in a circadian manner, behaves as an endogenous rhythms synchronizer, and it is used as a supplement to promote resynchronization of altered circadian rhythms. In this study, we tested the effect of melatonin administration on the circadian system in athletes. Two groups of athletes were treated with 100 mg day(-1) of melatonin or placebo 30 min before bed for four weeks. Daily rhythm of salivary melatonin was measured before and after melatonin administration. Moreover, circadian variables, including wrist temperature (WT), motor activity and body position rhythmicity, were recorded during seven days before and seven days after melatonin or placebo treatment with the aid of specific sensors placed in the wrist and arm of each athlete. Before treatment, the athletes showed a phase-shift delay of the melatonin circadian rhythm, with an acrophase at 05:00 h. Exercise induced a phase advance of the melatonin rhythm, restoring its acrophase accordingly to the chronotype of the athletes. Melatonin, but not placebo treatment, changed daily waveforms of WT, activity and position. These changes included a one-hour phase advance in the WT rhythm before bedtime, with a longer nocturnal steady state and a smaller reduction when arising at morning than the placebo group. Melatonin, but not placebo, also reduced the nocturnal activity and the activity and position during lunch/nap time. Together, these data reflect the beneficial effect of melatonin to modulate the circadian components of the sleep-wake cycle, improving sleep efficiency.

Alterations in redox homeostasis in the elite endurance athlete

BACKGROUND

The production of reactive oxygen (ROS) and nitrogen species (RNS) is a fundamental feature of mammalian physiology, cellular respiration and cell signalling, and essential for muscle function and training adaptation. Aerobic and anaerobic exercise results in alterations in redox homeostasis (ARH) in untrained, trained and well trained athletes. Low to moderate doses of ROS and RNS play a role in muscle adaptation to endurance training, but an overwhelming increase in RNS and ROS may lead to increased cell apoptosis and immunosuppression, fatigued states and underperformance.

OBJECTIVES

The objectives of this systematic review are: (a) to test the hypotheses that ARH occur in elite endurance athletes; following an acute exercise bout, in an endurance race or competition; across a micro-, meso- or macro-training cycle; following a training taper; before, during and after altitude training; in females with amenorrhoea versus eumenorrhoea; and in non-functional over-reaching (NFOR) and overtraining states (OTS); (b) to report any relationship between ARH and training load and ARH and performance; and (c) to apply critical difference values for measures of oxidative stress/ARH to address whether there is any evidence of ARH being of physiological significance (not just statistical) and thus relevant to health and performance in the elite athlete.

METHODS

Electronic databases, Embase, MEDLINE, and SPORTDiscus were searched for relevant articles. Only studies that were observational articles of cross-sectional or longitudinal design, and included elite athletes competing at national or international level in endurance sports were included. Studies had to include biomarkers of ARH; oxidative damage, antioxidant enzymes, antioxidant capacity, and antioxidant vitamins and nutrients in urine, serum, plasma, whole blood, red blood cells (RBCs) and white blood cells (WBCs). A total of 3,057 articles were identified from the electronic searches. Twenty-eight articles met the inclusion criteria and were included in the review.

RESULTS

ARH occurs in elite endurance athletes, after acute exercise, a competition or race, across training phases, and with natural or simulated altitude. A reduction in ARH occurs across the season in elite athletes, with marked variation around intensified training phases, between individuals, and the greatest disturbances (of physiological significance) occurring with live-high-train-low techniques, and in athletes competing. A relationship with ARH and performance and illness exists in elite athletes. There was considerable heterogeneity across the studies for the biomarkers and assays used; the sport; the blood sampling time points; and the phase in the annual training cycle and thus baseline athlete fitness. In addition, there was a consistent lack of reporting of the analytical variability of the assays used to assess ARH.

CONCLUSIONS

The reported biochemical changes around ARH in elite athletes suggest that it may be of value to monitor biomarkers of ARH at rest, pre- and post-simulated performance tests, and before and after training micro- and meso-cycles, and altitude camps, to identify individual tolerance to training loads, potentially allowing the prevention of non-functionally over-reached states and optimisation of the individual training taper and training programme.

Relationship between Inflammatory Cytokines and Indices of Cardiac Dysfunction following Intense Endurance Exercise

Objectives

Pro-inflammatory cytokines have been noted to increase following exercise but their relationship to exercise-induced cardiac dysfunction has not previously been investigated. We sought to evaluate whether exercise-induced cardiac dysfunction was associated with increases in cytokines, particularly the pro-inflammatory cytokines IL-1β, IL-12p70 and TNFα, which have been most implicated in cardiac pathology.

Methods

40 well-trained endurance athletes underwent evaluation prior to and immediately following one of four endurance sporting events ranging from 3 to 11 hours duration. Cytokines (IL-1β, IL-6, IL-8, IL-10, IL-12p70 and TNFα) were analyzed by flow cytometry from serum samples collected within 50 minutes of race completion. Cardiac troponin (cTnI) and B-type natriuretic peptide were combined with an echocardiographic assessment of cardiac function, and a composite of cTnI > 0.04 μg/L, BNP increase > 10 ng/L and a decrease in right ventricular ejection (RVEF) > 10% were prospectively defined as evidence of myocardial dysfunction.

Results

Relative to baseline, IL-6 IL-8 and IL-10 increased 8.5-, 2.9-, and 7.1-fold, respectively, P<0.0001. Thirty-one (78%), 19 (48%) and 18 (45%) of the athletes met the pre-specified criteria for significant cTnI, BNP and RVEF changes, respectively. TNFα, IL-12p70 were univariate predictors of ΔRVEF and ΔBNP whilst none of the anti-inflammatory cytokines were significantly associated with these measures. Ten athletes (25%, all athletes competing in the endurance event of longest duration) met criteria for exercise-induced myocardial dysfunction. In these 10 athletes with myocardial dysfunction, as compared to those without, there was significantly greater post-race expression of the pro-inflammatory cytokines IL-12p70 (8.1±3.8pg/ml vs. 2.5±2.6pg/ml, P<0.0001) and TNFα (6.5±3.1pg/ml vs. 2.0±2.5pg/ml, P<0.0001).

Conclusion

Cardiac dysfunction following intense endurance exercise was associated with increased expression of pro-inflammatory cytokines. This does not prove a causal relationship but provides rationale for further investigations into whether inflammation mediates exercise-induced myocardial dysfunction.

Oxidative Stress Is a Central Target for Physical Exercise Neuroprotection Against Pathological Brain Aging

Physical exercise is suggested for preventing or delaying senescence and Alzheimer's disease (AD). We have examined its therapeutic value in the advanced stage of AD-like pathology in 3xTg-AD female mice through voluntary wheel running from 12 to 15 months of age. Mice submitted to exercise showed improved body fitness, immunorejuvenation, improvement of behavior and cognition, and reduced amyloid and tau pathology. Brain tissue analysis of aged 3xTg-AD mice showed high levels of oxidative damage. However, this damage was decreased by physical exercise through regulation of redox homeostasis. Network analyses showed that oxidative stress was a central event, which correlated with AD-like pathology and the AD-related behaviors of anxiety, apathy, and cognitive loss. This study corroborates the importance of redox mechanisms in the neuroprotective effect of physical exercise, and supports the theory of the crucial role of oxidative stress in the switch from normal brain aging to pathological aging and AD.

Redox status and antioxidant response in professional cyclists during training

The aim of this study was to investigate whether different phases of training affect oxidative stress and antioxidant defences in professional cyclists. Ten professional cyclists, aged 21.8 ± 2.5 years, were enrolled in the study. They were classified into two groups of five athletes each one with similar nutritional intake excepting for the overload of vitamin C (1000 mg day(-1)) and E (400 mg day(-1)) supplementation in one of them. The cyclists of both groups performed the same exercise design, consisting of hard, tapering and recovery training periods. Total antioxidant capacity (TAC) of the diet, plasma oxygen radical absorption capacity (ORAC), lipid peroxidation (LPO), DNA damage (8-OHdG) and erythrocyte glutathione disulfide/glutathione ratio (GSSG:GSH(-1)) were measured. During the intense exercise trainings, the cyclists without vitamin supplements had the TAC of diet significantly lower than the supplemented group. Plasma ORAC, LPO and 8-OHdG were similar in both groups of athletes. Athletes with supplements had a basal LPO:ORAC(-1) ratio lower than that without supplements, but this ratio converged to the same level at the end of the training in both groups of cyclists. Both groups of cyclists showed similar changes in GSSG:GSH(-1) ratio and in GSSG and GSH levels along the study. The data suggest that well-trained athletes with suitable ultra-endurance training volume and intensity do not require antioxidant vitamin supplements to adapt their endogenous antioxidant defenses to exercise-induced ROS.

Bioactive compounds derived from the yeast metabolism of aromatic amino acids during alcoholic fermentation

Metabolites resulting from nitrogen metabolism in yeast are currently found in some fermented beverages such as wine and beer. Their study has recently attracted the attention of researchers. Some metabolites derived from aromatic amino acids are bioactive compounds that can behave as hormones or even mimic their role in humans and may also act as regulators in yeast. Although the metabolic pathways for their formation are well known, the physiological significance is still far from being understood. The understanding of this relevance will be a key element in managing the production of these compounds under controlled conditions, to offer fermented food with specific enrichment in these compounds or even to use the yeast as nutritional complements.

Effects of a freeze-dried juice blend powder on exercise-induced inflammation, oxidative stress, and immune function in cyclists

A freeze-dried fruit and vegetable juice powder (JUICE) was investigated as a countermeasure nutritional strategy to exercise-induced inflammation, oxidative stress, and immune perturbations in trained cyclists. Thirty-four cyclists (25 male, 9 female) were randomized to control (nonJUICE) or JUICE for 17 days. JUICE provided 230 mg·day(-1) of flavonoids, doubling the typical adult daily intake. During a 3-d period of intensified exercise (days 15-17), subjects cycled at 70%-75% V̇O2max for 2.25 h per day, followed by a 15-min time trial. Blood samples were collected presupplementation, post supplementation (pre-exercise), and immediately and 14-h post exercise on the third day of exercise. Samples were analyzed for inflammation (interleukin (IL)-6, IL-8; tumor necrosis factor alpha (TNFα); monocyte chemoattractant protein-1 (MCP-1)), oxidative stress (oxygen radical absorbance capacity (ORAC), ferric reducing ability of plasma (FRAP), reduced and oxidized glutathione, protein carbonyls), and innate immune function (granulocyte (G-PHAG) and monocyte (M-PHAG) phagocytosis and oxidative burst activity). A 2 (group) × 4 (time points) repeated measures ANOVA revealed significant time effects due to 3 days of exercise for IL-6 (396% increase), IL-8 (78% increase), TNFα (12% increase), MCP-1 (30% increase), G-PHAG (38% increase), M-PHAG (36% increase), FRAP (12.6% increase), ORAC (11% decrease at 14 h post exercise), and protein carbonyls (82% increase at 14 h post exercise) (p < 0.01). No significant interaction effects were found for any of the physiological measures. Although providing 695 gallic acid equivalents of polyphenols per day, JUICE treatment for 17 days did not change exercise-induced alterations in inflammation and oxidative stress or immune function in trained cyclists after a 3-day period of overreaching.

Exercise and melatonin in humans: reciprocal benefits

The aim of this review is to update the reader as to the association between physical exercise and melatonin, and to clarify how the melatonin rhythm may be affected by different types of exercise. Exercise may act as a zeitgeber, although the effects of exercise on the human circadian system are only now being explored. Depending on the time of the day, on the intensity of light, and on the proximity of the exercise to the onset or decline of the circadian production of melatonin, the consequence of exercise on the melatonin rhythm varies. Moreover, especially strenuous exercise per se induces an increased oxidative stress that in turn may affect melatonin levels in the peripheral circulation because indole is rapidly used to combat free radical damage. On the other hand, melatonin also may influence physical performance, and thus, there are mutually interactions between exercise and melatonin production which may be beneficial.

Acute exercise increases plasma total antioxidant status and antioxidant enzyme activities in untrained men

Antioxidant defences are essential for cellular redox regulation. Since free-radical production may be enhanced by physical activity, herein, we evaluated the effect of acute exercise on total antioxidant status (TAS) and the plasma activities of catalase, glutathione reductase, glutathione peroxidase, and superoxide dismutase and its possible relation to oxidative stress resulting from exercise. Healthy untrained male subjects (n = 34) performed three cycloergometric tests, including maximal and submaximal episodes. Venous blood samples were collected before and immediately after each different exercise. TAS and enzyme activities were assessed by spectrophotometry. An increase of the antioxidant enzyme activities in plasma was detected after both maximal and submaximal exercise periods. Moreover, under our experimental conditions, exercise also led to an augmentation of TAS levels. These findings are consistent with the idea that acute exercise may play a beneficial role because of its ability to increase antioxidant defense mechanisms through a redox sensitive pathway.