Oxidative stress and nitrite dynamics under maximal load in elite athletes: relation to sport type

n-3 Polyunsaturated Fatty Acids Are Associated with Stable Nitric Oxide Metabolites in Highly Trained Athletes

BACKGROUND

The aim of this study was to investigate the relationships between levels of n-3 essential polyunsaturated fatty acids (n-3 PUFAs) and stable nitric oxide (NO) metabolites in the plasma of athletes.

METHODS

Highly trained cross-country skiers (males, n = 39) were examined. The fatty acid profile of the total plasma lipids was determined by gas chromatography. The plasma NO level was studied by a colorimetric method via reaction with Griess reagent.

RESULTS

A widespread deficiency of essential n-3 PUFAs in the plasma of athletes (more than 80% of the subjects) was demonstrated in association with an imbalance in the levels of nitrates (NO3) and nitrites (NO2). A lower value of n-3 linolenic acid in the plasma (0.21 mol/%) was associated with a NO3 level below the normal range (n-3 C18:3 and NO3 Rs = 0.461; p = 0.003). Higher levels of n-3 eicosapentaenoic acid (0.8 mol/%) were associated with a concentration of NO2 above the normal value (n-3 C20:5 and NO2 Rs = 0.449; p = 0.004).

CONCLUSION

For the first time, the participation of essential n-3 PUFAs in the nitrite-nitrate pathway of NO synthesis in highly trained skiers was demonstrated.

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.

The Influence of Continuous and Interval Aerobic Training on the Oxidative Status of Woman Basketball Players

Oxidative stress is a state of disturbed balance between reactive oxygen species and reactive nitrogen species on the one hand and on the other antioxidant protection. Increased oxygen consumption during exercise could be the cause of oxidative stress. The aim of this study was to monitoring the parameters of oxidative stress and components of antioxi-dative defense during the training process, establish oxidative status basketball players in standby mode after the load caused by two types of aerobic training - continuous aerobic and interval (HIIT) training.

As part of a longitudinal experimental study selected a sample of 12 basketball players during the training process. All respondents were female, age 14 to 27 years. The study was conducted in preparatory stage. Oxidative status was determined through the index of lipid peroxidation (measured as TBARS), nitric oxide (NO) in the form of nitrite (NO2) levels of superoxide anion radicals (O2) and hydrogen peroxide (H2O2), while the activity of the enzyme protection from oxidative damage was determined through superoxide dismutase (SOD), catalase (CAT) and reduction glutathione (GSH).

The group analyzed in relation to the type of the training intervention was significantly different from the results in the test in the parameters of NO and TBARS. When the enzyme activity of protection against oxidative damage statistically significant differences between groups arise for CAT and GSH.

The emergence of oxidative stress is not necessary phenomenon of high aerobic training load, training leads to the maintenance of physiological balance in the body.

Physical, physiological and psychological profiles of elite Turkish taekwondo athletes

Study aim: To identify the physical, physiological and psychological profiles of elite Turkish taekwondo athletes.

Material and methods: Twelve players of the Turkish national taekwondo team (age = 22.7 ± 2.8 years, BMI = 22.2 ± 1.4 kg/m2, body fat = 12.8 ± 3.4%) participated in the study. Anthropometric measurements including leg length and foot size were assessed. Maximal oxygen uptake, explosive power of leg extensors, isokinetic peak torque, muscular endurance, anaerobic power, agility, flexibility, maximal speed, reaction time, and postural balance were examined by incremental treadmill running, vertical jump, isokinetic strength, sit-ups and push-ups, Wingate, shuttle run, sit-and-reach, 30-meter sprint, multiple-choice reaction time, and General Postural Stability and Athlete Single Leg stability tests, respectively. Psychological characteristics including mental skills and mood states were evaluated using OMSAT-3 and POMS tests.

Results: VO2max, isokinetic peak torque and Wingate test mean power values were 54.1 ± 4.4 mL ∙ kg−1 ∙ min−1, 191.7 ± 19.2 N ∙ m, and 9 ± 0.7 W/kg, respectively. Postural stability index 0.18 ± 0.06, single leg stability index 0.82 ± 0.11, reaction time 0.344 ± 0.032 s, 10 × 5-m shuttle run 17.09 ± 0.68 s, 30-meter sprint 4.60 ± 0.23 s, and vertical jump 43.5 ± 6.1 cm were the other values reported. The highest scores for the 12 mental skills in OMSAT-3 were for goal setting (6.25 ± 0.45) and self-confidence (6.16 ± 0.45). The lowest score was for Imagery (5.64 ± 0.36). The results of six mood states of POMS showed higher scores on the Vigor-activity, Anger-Hostility and Tension-Anxiety scales and lower scores on Depression-Dejection, Fatigue-Inertia and Confusion-Bewilderment than norms.

Conclusions: The findings of this study revealed the physical, physiological, and psychological characteristics in taekwondo. The results of the tests could be useful for performance assessment of taekwondo players.

Training session intensity affects plasma redox status in amateur rhythmic gymnasts

PURPOSE

The aim of this study was to examine systemic responses of oxidant/antioxidant status following 2 training sessions of different intensity in amateur rhythmic gymnasts.

METHODS

Before the experimental training, 10 female gymnasts performed a gradually increased exercise test to assess maximal heart rate, maximal oxygen consumption, and anaerobic threshold. They executed 2 intermittent training sessions separated by 48 h of recovery (48 h-post R): the first was performed at low-moderate intensity (LMI) and the second at high intensity (HI). Blood samples were collected immediately pre- and post-training and 48 h-post R. Hydroperoxide level (OxL) and total antioxidant capacity (TAC) were photometrically measured.

RESULTS

OxL was significantly higher in post-training and 48 h-post R following HI than the same conditions after an LMI session (HI vs. LMI post-training: 381.10 ± 46.17 (mean ± SD) vs. 344.18 ± 27.94 Units Carratelli (U.CARR); 48 h-post R: 412.21 ± 26.61 vs. 373.80 ± 36.08 U.CARR). There was no change in TAC between the 2 training sessions investigated. In LMI training, OxL significantly decreased in post-training and increased to reach the baseline at 48 h-post R, whereas TAC increased only at 48 h-post R. In HI training, OxL significantly increased to reach a high oxidative stress 48 h-post R, whereas TAC was lower in post-training than pre-training.

CONCLUSION

The pattern of OxL and TAC levels implies different regulation mechanisms by HI and LMI training sessions. High oxidative stress induced by an HI protocol might be associated with both insufficient TAC and recovery time at 48 h necessary to restore redox balance.

The Impact of Resveratrol Supplementation on Inflammation Induced by Acute Exercise in Rats: Il6 Responses to Exercise

Severe physical activity leads to a sharp increase in free radicals, an oxidative stress, inflammation, and tissue damage. Resveratrol as one of the antioxidants can be effective in preventing the effects of oxidative stress. Therefore, the present study was aimed to evaluate the effect of trans-resveratrol supplementation and training exercise on inflammation-related factors. Sixty-four male Wistar rats were divided into six groups, each group consisting of 16 animals: 1) excursive + trans-resveratrol, 2) exercise group, 3) trans-resveratrol group, and 4) control group. Following the familiarization sessions, a more consistent protocol with an intensity of 65% vo2 max was performed for 12 weeks. Afterward, half of the mice in each group received acute exercise training with an intensity of 70-75% of vo2 max at the age of 20 weeks, until reaching the disability level. Finally, the levels of inflammatory markers were measured using special kits. Our findings depicted that inflammatory factors such as CPR, TNF-α, IL-6, and IL-7 were not affected by endurance protocol (P > 0.05), whereas, they were significantly increased by acute exercise training (P > 0.05). Additionally, we found that RES supplements led to a decrease in CPR and IL-6 levels, while not affecting TNF-α and IL-17 levels. According to available evidence, RES appears to have anti-inflammatory and protective effects during exercise by reducing inflammatory factors. Further studies are required to clarify the role of trans-resveratrol supplementation after exercise training.

Monitoring Exercise-Induced Muscle Fatigue and Adaptations: Making Sense of Popular or Emerging Indices and Biomarkers

Regular exercise with the appropriate intensity and duration may improve an athlete’s physical capacities by targeting different performance determinants across the endurance–strength spectrum aiming to delay fatigue. The mechanisms of muscle fatigue depend on exercise intensity and duration and may range from substrate depletion to acidosis and product inhibition of adenosinetriphosphatase (ATPase) and glycolysis. Fatigue mechanisms have been studied in isolated muscles; single muscle fibers (intact or skinned) or at the level of filamentous or isolated motor proteins; with each approach contributing to our understanding of the fatigue phenomenon. In vivo methods for monitoring fatigue include the assessment of various functional indices supported by the use of biochemical markers including blood lactate levels and more recently redox markers. Blood lactate measurements; as an accompaniment of functional assessment; are extensively used for estimating the contribution of the anaerobic metabolism to energy expenditure and to help interpret an athlete’s resistance to fatigue during high intensity exercise. Monitoring of redox indices is gaining popularity in the applied sports performance setting; as oxidative stress is not only a fatigue agent which may play a role in the pathophysiology of overtraining syndrome; but also constitutes an important signaling pathway for training adaptations; thus reflecting training status. Careful planning of sampling and interpretation of blood biomarkers should be applied; especially given that their levels can fluctuate according to an athlete’s lifestyle and training histories.

Preparatory training attenuates drastic response of the insulin-like growth factor binding protein 1 at the point of maximal oxygen consumption in handball players

BACKGROUND

Intensive exercise changes physiological need for glucose and several biochemical pathways responsible for its metabolism response. Among them are those which involve insulin, insulin-like growth factor (IGF-1), and IGF-binding proteins (IGFBPs). Different types and degrees of exercise, as well as an athlete's fitness, may induce a range of responses regarding concentrations and time needed for the alteration. The idea of the work was to find out whether and how insulin/IGF axis responds to additional physical activity in the already trained subjects and if so, is the adaptation potentially beneficial from the aspect of metabolic control.

METHODS

The effect of 4-week intensive training on campus (preparatory training) on the levels of insulin, IGF-1, and IGFBPs during maximal progressive exercise test (MPET) on a treadmill was compared to the results obtained during MPET conducted after a regular training season of a female elite handball team (n = 17, age: 17 ± 1 years, height: 171 ± 8 cm, weight: 65 ± 8 kg, body mass index: 22 ± 1 kg/m2 at the beginning of the study; there were no significant changes at the end). Serum samples were obtained from players immediately before the test (basal), at the end of the test after reaching the point of maximal oxygen consumption (VO2max), and after recovery.

RESULTS

The concentration of insulin decreased at VO2max, but remained higher in players after preparatory training (12.2 ± 2.5 mU/L vs. 8.9 ± 4.4 mU/L, p = 0.049). The level of IGFBP-1 decreased in players at VO2max in either case of training, but it remained much higher in tests performed after the preparatory regime than before (p = 0.029). Concentrations of IGF-1, IGFBP-2, -3, and -4 did not change significantly.

CONCLUSION

The inverse relation between insulin and IGFBP-1 was lost during MPET, as these 2 molecules changed in the same direction. The results obtained suggest less severe stress-induced depression of insulin and IGFBP-1 after preparatory training. But another metabolic mechanism cannot be excluded, and that is potentially impaired insulin sensitivity resulting in higher level of IGFBP-1.

Oxidative Stress in Training, Overtraining and Detraining: from Experimental to Applied Research

According to the hormesis theory, the responses of biological systems to stressors in exercise training may be explained by a U-shaped curve with inactivity and overtraining as the two endpoints. Both of these endpoints decrease physiological functions. Markers of oxidative stress may be important parameters for biological monitoring of athletes. Numerous studies have shown that acute exercise has the potential to induce oxidative stress, but regular exposure to an increased level of prooxidants leads to upregulation of the endogenous antioxidative defence system (ADS) of an athlete. Studies that explored the redox state in athletes during the competitive season showed that the antioxidative status changes depending on the training load and training phase. During the training season, a state of fatigue known as overtraining may occur, which results from an excessive training load. Oxidative stress has been suggested as one of the causes of overtraining syndrome. Based on the existing studies, it can be said that a connection exists, but whether oxidative stress is a cause or a consequence of overtraining is yet to be clarified. Furthermore, detraining (training reduction or cessation) leads to a partial or complete loss of training-induced anatomical, physiological and performance adaptations; therefore, it seems reasonable to assume that changes in ADS are also reversible.

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.

Oxidative stress status in elite athletes engaged in different sport disciplines

Exercise training may increase production of free radicals and reactive oxygen species in different ways. The training type and intensity may influence free radicals production, which leads to differences in oxidative stress status between athletes, but the results of the previous studies are incosistent. The aim of our study was to estimate oxidative stress status in elite athletes engaged in different sport disciplines. The study included 39 male highly skilled professional competitors with international experience (2 Olympic players): 12 wrestlers, 14 soccer players and 13 basketball players in whom we determined the levels of advanced oxidation protein products (AOPP) and malondialdehyde (MDA), as markers of oxidative stress and the total antioxidative capacity (ImAnOX) using commercially available assay kits. The mean AOPP concentration was not significantly different between soccer players, wrestler and basketball players (60.0 ± 23.0 vs. 68.5 ± 30.8 and 80.72 ± 29.1 μmol/L respectively). Mean ImAnOX concentration was not different between soccer players (344.8 ± 35.6 μmol/L), wrestlers (342.5 ± 36.2 μmol/L) and basketball players (347.95 ± 31.3 μmol/L). Mean MDA concentration was significantly higher in basketball players (1912.1 ± 667.7 ng/mL) compared to soccer players (1060.1 ± 391.0 ng/mL, p=0.003). In spite of this fact, oxidative stress markers levels were increased compared to referral values provided by the manufacturer. Type of sports (soccer, wrestler or basketball) have no impact on the levels of oxidative stress markers. Elite sports engagement is a potent stimulus of oxidative stress that leads to the large recruitment of antioxidative defense. Oxidative stress status monitoring followed by appropriate use of antioxidants is recommended as a part of training regime.

Physical and physiological profiles of taekwondo athletes

Taekwondo has evolved into a modern-day Olympic combat sport. The physical and physiological demands of modern-day taekwondo competition require athletes to be competent in several aspects of fitness. This review critically explores the physical and physiological characteristics of taekwondo athletes and presents implications for training and research. International taekwondo athletes possess low levels of body fat and a somatotype that characterises a blend of moderate musculoskeletal tissue and relative body linearity. While there is some variation in the maximum oxygen uptake of taekwondo athletes, moderate to high levels of cardio-respiratory fitness are necessary to support the metabolic demands of fighting and to facilitate recovery between consecutive matches. Taekwondo athletes demonstrate high peak anaerobic power characteristics of the lower limbs and this attribute appears to be conducive to achieving success in international competition. The ability to generate and sustain power output using both concentric and 'stretch-shortening cycle' muscle actions of the lower limbs may be important to support the technical and tactical actions in combat. Taekwondo competitors also display moderate to high maximum dynamic strength characteristics of the lower and upper extremities, and moderate endurance properties of the trunk and hip flexor musculature. The dynamic nature of the technical and tactical actions in the sport demand high flexibility of the lower limbs. More extensive research is required into the physical and physiological characteristics of taekwondo athletes to extend existing knowledge and to permit specialised conditioning for different populations within the sport.

The effects of 16 weeks of intensive cycling training on seminal oxidants and antioxidants in male road cyclists

OBJECTIVE

To examine the effects of 16 weeks of intensive cycling training on seminal reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), catalase, and total antioxidant capacity (TAC) in male road cyclists.

DESIGN

Repeated measures design.

SETTING

The Exercise Physiology Laboratory of the Urmia University.

PARTICIPANTS

Twenty-four healthy nonprofessional male road cyclists (aged 17-26 years) participated in this study.

INTERVENTIONS

All subjects participated in 16 weeks of intensive cycling training. The semen samples were collected, respectively, at baseline (T1), immediately (T2), 12 (T3), and 24 (T4) hours after the last training session in week 8; immediately (T5), 12 (T6), and 24 (T7) hours after the last training session in week 16; and 7 (T8) and 30 (T9) days after the last training session in week 16.

MAIN OUTCOME MEASURES

Total antioxidant capacity and SOD were measured by colorimetric assay. The levels of ROS were measured by a chemiluminescence assay. Malondialdehyde levels were measured by thiobarbituric acid reactive substance assay. Catalase was measured by monitoring the initial rate of disappearance of hydrogen peroxide (initial concentration 10 mM) at 240 nm.

RESULTS

The levels of seminal ROS and MDA increased (P < 0.008) and remained high after 30 days of recovery. The levels of seminal SOD, catalase, and TAC decreased (P < 0.008) and remained low after 30 days of recovery (P < 0.008).

CONCLUSIONS

Sixteen weeks of intensive cycling training may have deleterious consequences for spermatozoa and hence may affect sperm healthy parameters in male cyclists.

Alteration in basal redox state of young male soccer players after a six-month training programme

Despite worldwide popularity of soccer, there are still insufficient data about the effects of training process on oxidative stress-induced damage, which may occur during chronic exercise. The present study aimed to determine the effects of a six-month training programme on basal redox status of young male soccer players. The study included 26 male soccer players, aged 12-13, who participated in a six-month training programme, and 26 age-matched non-athletes who were not implemented in the training process. Blood samples were collected (before and after six-month training programme) in order to measure the following oxidative stress markers: index of lipid peroxidation (measured as TBARS), nitrites (NO2-), superoxide anion radical (O2-), hydrogen peroxide (H2O2), superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH) level. After six months, the levels of TBARS and NO2- were significantly increased, while the O2- and H2O2 remained unchanged. On the other hand, SOD and CAT activity increased, while GSH decreased. A carefully prepared training programme could strengthen most components of antioxidant defence systems and, except lipid peroxidation, does not promote oxidative stress in response to regular physical activity. These findings could help in the improvement of training programmes for young athletes.

Changes in athlete's redox state induced by habitual and unaccustomed exercise

The purpose of this study was to assess the influence of sport-specific and nonspecific bouts of exercise on athletes' redox state. Blood samples were collected from 14 handball players immediately before and after graded exercise test on the cycle ergometer and handball training. Levels of superoxide anion radical (O(2) (-)), hydrogen peroxide (H(2)O(2)), nitrites (NO(2) (-)) as markers of nitric oxide, index of lipid peroxidation (TBARs), glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) activity were determined. Exercise intensity was assessed by a system for heart rate (HR) monitoring. Average athletes' HR was not significantly different between protocols, but protocols differed in total time and time and percentage of time that athletes spent in every HR zone. The laboratory exercise test induced a significant increase of H(2)O(2) and TBARs as well as the decrease of the SOD and CAT activity, while after specific handball training, levels of NO(2) (-) were increased and SOD activity decreased. It seems that unaccustomed short intensive physical activity may induce oxidative stress in trained athletes, while sport-specific activity of longer duration and proper warm-up period may not. Further research should show whether the change of protocol testing and the implementation of various supplementations and manual methods can affect the redox equilibrium.

Physical exercise ameliorates deficits induced by traumatic brain injury

The extent and depth of traumatic brain injury (TBI) remains a major determining factor together with the type of structural insult and its location, whether mild, moderate or severe, as well as the distribution and magnitude of inflammation and loss of cerebrovascular integrity, and the eventual efficacy of intervention. The influence of exercise intervention in TBI is multiple, ranging from anti-apoptotic effects to the augmentation of neuroplasticity. Physical exercise diminishes cerebral inflammation by elevating factors and agents involved in immunomodulatory function, and buttresses glial cell, cerebrovascular, and blood-brain barrier intactness. It provides unique non-pharmacologic intervention that incorporate different physical activity regimes, whether dynamic or static, endurance or resistance. Physical training regimes ought necessarily to be adapted to the specific demands of diagnosis, type and degree of injury and prognosis for individuals who have suffered TBI.