Oxidative Stress After Three Different Intensities of Running

Effect of 2 weeks rest-pause on oxidative stress and inflammation in female basketball players

Intense exercise leads to increased production of free radicals, resulting in an inflammatory response in athletes. For this reason, it was decided to investigate whether a single intensive exercise until exhaustion applied after a 2-week rest period would result in a violation of the pro-oxidant-antioxidant balance. Twenty-seven trained female basketball players (age: 16.55 ± 0.96 years, body mass: 66.40 ± 13.68 kg, height: 173.45 ± 5.14 cm) were enrolled to the study following the application of inclusion and exclusion criteria. Study was conducted at the end of the competitive training phase. Participants underwent incremental treadmill exercise, with blood samples collected before the test, immediately post-exercise, and after a 3-h restitution period. Total antioxidant capacity (TAC) levels increased significantly after exercise and remained unchanged after 3 h. Concentration of interleukin-10 (IL-10) and creatine kinase (CK) significantly increased after exercise and then decreased. Concentration of interleukin-2 (IL-2) was significantly reduced immediately and 3 h after exercise, while interleukin-13 (IL-13), interleukin-1α (IL-1α), and tryptophan (TRP) decreased 3 h after exercise. No significant changes were observed in other biochemical parameters. Obtained results show an increased antioxidant capacity which reduced oxidative stress and inflammation in response to intense exercise indicating that rested athletes have a high adaptation and elevated tolerance to effort.

Biochemical and Hormone Markers in Firefighters: Effects of "Search, Rescue, and Survival Training" and Its Recovery

ABSTRACT

Ponce, T, Mainenti, MRM, de Barros, T, Cahuê, FLC, Fernanda, C, Piazera, BKL, Salerno, VP, and Vaisman, M. Biochemical and hormone markers in firefighters: effects of "search, rescue, and survival training" and its recovery. J Strength Cond Res 38(4): e189-e201, 2024-This study aimed to evaluate the hormonal and biochemical responses in military firefighter cadets to a search, rescue, and survival training (SRST) course. Forty-three male volunteers participated in the SRST over 15 days consisting of intense physical effort, sleep deprivation, and a survival period with food deprivation. At 3 timepoints (baseline, SRST, and 1 week rec), subjects submitted to blood collections, body composition examinations, physical performance evaluations, and cognitive function tests. After the SRST, lower values were registered for testosterone (764.0; 565.1-895.0 to 180.6; 133.6-253.5 ng·dl -1 ) and insulin-like growth factor-1 (IGF-1) (217; 180-238 to 116; 102-143 ng·ml -1 ). Increases were observed for cortisol (9.7; 8.2-11.7 to 18.3; 16.5-21,2 μg·dl -1 ), growth hormone (GH) (0.11; 0.06-0.20 to 2.17; 1.4-3.4 ng·ml -1 ), CP, GSSG, lactate dehydrogenase, alanine aminotransferase, and aspartate aminotransferase as well as the antioxidant response of superoxide dismutase and glutathione peroxidase. The values of gamma-glutamyl transferase were reduced. After 1 week of recovery, levels of GH, creatine kinase, GSH, and GSSG returned to baseline values ( p < 0.05). Vertical jump performance presented a regular positive correlation with testosterone (rho = 0.56 and p < 0.0001) and a strong negative correlation with cortisol (rho = -0.61 and p < 0.0001). Body fat showed a regular and positive correlation with both testosterone and IGF-1. We conclude that participation in the SRST caused significant hormonal and biochemical changes in individuals that correlated with a loss in physical performance. Importantly, the results suggest the need for longer recovery times before a return to normal military duties.

Acute Antioxidant Response to Two Types of Exercises: 2000 M Run vs. Burpee Test

Physical activity results in oxidative stress, as evidenced by the increased production of reactive oxygen, nitrogen species, and inflammatory mediators. The management of these components is instrumental for antioxidant adaptation to exercise and post-exercise recovery. Therefore, the present report aims to study the antioxidant response to two types of exercise (a 2000 m run and a burpee test) in healthy volunteers after a long period of inactivity (1-2 months). Antioxidant enzyme activities and oxidative stress markers (protein carbonyls and malondialdehyde content) were measured in neutrophils, peripheral blood mononuclear cells, and plasma. These parameters were determined under basal conditions and immediately post-exercise. Compared to those in basal state, neutrophil superoxide dismutase (28.3 vs. 22.9 pkat/109 cells), glutathione peroxidase (147.5 vs. 120.1 nkat/109 cells), and catalase (106.3 vs. 57.9 k/109 cells) were activated significantly (p < 0.05) after the burpee test. Peripheral blood mononuclear cells exhibited only significant (p < 0.05) catalase activation (113.6 vs. 89.4 k/109 cells) after the burpee test. Other enzymes, such as glutathione reductase and myeloperoxidase, tended to increase post-exercise, although the differences from baseline were not significant. Finally, compared to basal conditions, the protein carbonyl (24.5 vs. 14.5 mmol/L) and malondialdehyde (39.6 vs. 18.3 mmol/L) contents increased significantly (p < 0.05) in neutrophils and in plasma (115.1 vs. 97.8 and 130.2 vs. 123.4 μmol/L, respectively) after the burpee test. In conclusion, high-intensity exercise seems to induce immediate oxidative stress in inactive individuals, and the acute antioxidant response was slightly greater after the burpee test than after the 2000 m run. Glutathione-dependent antioxidant systems are activated immediately as protective mechanisms.

Effects of muscle damage indicators and antioxidant capacity after interval training on the 800-m records of adolescent middle-distance runners

To examine the effect of 10-week interval training (IT) at varying intensities on serum muscle damage indicators and antioxidant capacity and determine its effect on the 800-m records of adolescent middle-distance runners. Twenty male high-school middle-distance runners were randomized between the high-intensity IT (HIIT; n=10) and the medium-intensity IT (MIIT; n=10) groups. Three sessions/week for 10 weeks (total of 30 sessions) were performed; one session of IT was for 60 min. The high and medium exercise intensities were set at 90%-95% and 60%-70% heart rate reserve (HRR), respectively. Intensity at rest was 40% HRR for both groups. Weight training was performed at 60%-70% of one repetition maximum for two sessions/week. The changes in serum muscle damage indicators and antioxidant capacity in the two groups were measured, and their effects on the 800-m records were analyzed. The 10-week training reduced serum muscle damage indicators in middle-distance runners, but only the HIIT group displayed a decrease in creatine kinase. For the change in antioxidant capacity, the two groups demonstrated no significant change in malondialdehyde (MDA), whereas the HIIT group exhibited a significant increase in super-oxide dismutase (SOD). IT also reduced the 800-m records in middle-distance running, and the effect was stronger in the HIIT group. In conclusion, 10-week HIIT can have a positive effect on muscle damage indicators, showed a significant increase in SOD as a key indicator of anti-oxidant capacity, and improved the 800-m records in middle-distance runners.

Promoting a pro-oxidant state in skeletal muscle: Potential dietary, environmental, and exercise interventions for enhancing endurance-training adaptations

Accumulating evidence now shows that supplemental antioxidants including vitamin C, vitamin E and N-Acetylcysteine consumption can suppress adaptations to endurance-type exercise by attenuating reactive oxygen and nitrogen species (RONS) formation within skeletal muscle. This emerging evidence points to the importance of pro-oxidation as an important stimulus for endurance-training adaptations, including mitochondrial biogenesis, endogenous antioxidant production, insulin signalling, angiogenesis and growth factor signaling. Although sustained oxidative distress is associated with many chronic diseases, athletes have, on average, elevated levels of certain endogenous antioxidants to maintain redox homeostasis. As a result, trained athletes may have a better capacity to buffer oxidants during and after exercise, resulting in a reduced oxidative eustress stimulus for adaptations. Thus, higher levels of RONS input and exercise-induced oxidative stress may benefit athletes in the pursuit of continuous endurance training redox adaptations. This review addresses why athletes should be looking to enhance exercise-induced oxidative stress and how it can be accomplished. Methods covered include high-intensity interval training, hyperthermia and heat stress, dietary antioxidant restriction and modified antioxidant timing, dietary antioxidants and polyphenols as adjuncts to exercise, and vitamin C as a pro-oxidant.

Physical Activity and Male Reproductive Function: A New Role for Gamete Mitochondria

Several studies demonstrated that some types of physical exercise might affect male reproductive potential, even though the potential mechanisms involved in the modulation of sperm quality remain poorly understood. Therefore, we propose a new role for gamete mitochondria as a key hub that coordinates molecular events related to the effects induced by physical exercise.

Effect of Different Exercise Modalities on Oxidative Stress: A Systematic Review

Exercise-induced benefits are being increasingly recognized in promoting health and preventing diseases. However, initial adaption to exercise response can have different effects on cells, including an increase in the formation of oxidants and inflammatory mediators that ultimately leads to oxidative stress, but this scenario depends on the exercise type and intensity and training status of the individual. Therefore, we aimed to understand the effect of different types of exercise on oxidative stress. Indeed, exercise-induced minimum oxidative stress is required for regulating signaling pathways. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, a search for relevant articles was carried out on PubMed/Medline, ISI Web of Science, and Google Scholar using a broad range of synonyms such as oxidants, reactive oxygen species (ROS), oxidative stress, exercise, physical training, aerobic exercise, and strength exercise until 2019. This study selected a total of 18 articles for assessing the oxidative damage using various parameters such as malondialdehyde (MDA), protein carbonyl (PCO), and F1-isoprostanes and enzymatic antioxidants. We observed that any type of exercise can increase the oxidative damage in an exercise type and intensity manner. Further, the training status of the individual and specific oxidative damage marker plays a crucial role in predicting earlier oxidative damage in the exercise condition. However, some of the studies that we included for review did not perform follow-up evaluations. Therefore, follow-up programs using larger numbers need to be performed to confirm our findings.

Effects of grape juice consumption on muscle fatigue and oxidative stress in judo athletes: a randomized clinical trial

Physiological levels of reactive oxygen species (ROS) are important for intracellular and extracellular redox regulation in signaling and defense processes. Strenuous exercise can also contribute to this imbalance, and the muscle fatigue, evidenced by impaired strength or power generation, can be caused by various reasons, including oxidative stress. Antioxidants can prevent the formation of ROS by intercepting free radicals. Twenty judo athletes were included in this randomized, double-blind clinical trial into grape juice and placebo groups, and they consumed grape juice or placebo daily for 14 days in a crossover model. The outcomes were analyzed before and after combat simulations. The upper limb strength was higher in the grape juice group than in the placebo (p [group] = 0.003). The lipid damage levels were 10% higher in the placebo group (p [interaction] = 0.048). During the pre-exercise, the placebo group showed 19% more DNA damage than the grape juice group. The superoxide dismutase activity was 80% lower in the grape juice group (p [interaction] < 0.001). The consumption of grape juice can improve parameters of oxidative stress by reducing the lipid and DNA damage.

CARNOSINE AVOIDS THE OXIDATIVE DAMAGE CAUSED BY INTENSE EXERCISE ON RAT SOLEUS MUSCLE

ABSTRACT Introduction: Intense physical exercise affects the balance between the production of reactive oxygen species and antioxidant defense in the muscle. Carnosine is a cytoplasmic dipeptide composed of the amino acids β-alanine and histidine. Objective: This study aimed to evaluate the effect of carnosine and its precursor β-alanine on oxidative damage caused by intense physical exercise in the soleus muscle of rats. Methods: Male Wistar rats weighing between 200 and 240 g were divided into four groups: control, exercise, exercise + β-alanine and exercise + carnosine. The animals from the groups that underwent the exercise ran on a treadmill for 60 minutes at 25 m/minute. Factors related to muscle damage and oxidative stress were assessed in soleus muscle homogenate and blood serum. Results: The exercise promoted muscle damage, as observed through increased serum activity of enzymes aspartate aminotransferase and creatine kinase. It also induced oxidative stress in soleus muscle, as seen by the increased activity of the enzymes glutathione peroxidase and glutathione reductase, decreased concentration of reduced glutathione, and increased concentration of malondialdehyde, an indicator of lipid peroxidation. Carnosine kept the creatine kinase, glutathione peroxidase and glutathione reductase enzyme activity values, and the concentration of reduced glutathione and malondialdehyde, close to those of the control group. Conclusion: The results indicate that pretreatment with carnosine protected the rat soleus muscle against oxidative damage and consequent injury caused by intense physical exercise. Level of evidence II; Therapeutic studies-Investigating the treatment results.

Strenuous Acute Exercise Induces Slow and Fast Twitch-Dependent NADPH Oxidase Expression in Rat Skeletal Muscle

The enzymatic complex Nicotinamide Adenine Dinucleotide Phosphate (NADPH) oxidase (NOx) may be the principal source of reactive oxygen species (ROS). The NOX2 and NOX4 isoforms are tissue-dependent and are differentially expressed in slow-twitch fibers (type I fibers) and fast-twitch fibers (type II fibers) of skeletal muscle, making them different markers of ROS metabolism induced by physical exercise. The aim of this study was to investigate NOx signaling, as a non-adaptive and non-cumulative response, in the predominant fiber types of rat skeletal muscles 24 h after one strenuous treadmill exercise session. The levels of mRNA, reduced glycogen, thiol content, NOx, superoxide dismutase, catalase, glutathione peroxidase activity, and PPARGC1α and SLC2A4 gene expression were measured in the white gastrocnemius (WG) portion, the red gastrocnemius (RG) portion, and the soleus muscle (SOL). NOx activity showed higher values in the SOL muscle compared to the RG and WG portions. The same was true of the NOX2 and NOX4 mRNA levels, antioxidant enzymatic activities, glycogen content. Twenty-four hours after the strenuous exercise session, NOx expression increased in slow-twitch oxidative fibers. The acute strenuous exercise condition showed an attenuation of oxidative stress and an upregulation of antioxidant activity through PPARGC1α gene activity, antioxidant defense adaptations, and differential gene expression according to the predominant fiber type. The most prominent location of detoxification (indicated by NOX4 activation) in the slow-twitch oxidative SOL muscle was the mitochondria, while the fast-twitch oxidative RG portion showed a more cytosolic location. Glycolytic metabolism in the WG portion suggested possible NOX2/NOX4 non-regulation, indicating other possible ROS regulation pathways.

Aerobic Physical Exercise as a Neuroprotector Strategy for Ethanol Binge-Drinking Effects in the Hippocampus and Systemic Redox Status in Rats

The heavy and episodic EtOH drinking pattern, equivalent to weekend consumption, characterizes the binge-drinking pattern and promotes a misbalance of encephalic metabolic functions, concurring to neurodegeneration and cerebral dysfunction. And for being a legal drug, it has global public health and social relevance. In this way, we aimed to investigate the effects of physical training, in a treadmill, on the deleterious effects of EtOH on hippocampal functions, related to memory and learning. For this, we used 40 Wistar rats, divided into four groups: Control group, Trained group (trained animals with doses of distilled water), EtOH group (nontrained animals with doses of 3 g/kg/day of EtOH, 20% w/v), and Trained+EtOH group (trained animals exposed to EtOH). The physical exercise was performed by running on a treadmill for 5 days a week for 4 weeks, and all doses of EtOH were administered through intragastric gavage in four repeated cycles of EtOH in binge. After the experimental period, the animals were submitted to the object recognition task and Morris water maze test, and after being euthanized, the blood and hippocampus were collected for Trolox Equivalent Antioxidant Capacity (TEAC), Reduced Glutathione Content (GSH), and Nitrite and Lipid Peroxidation (LPO) level measurements. Our results showed that EtOH caused marked oxidative stress and mnemonic damage, and the physical exercise promoted neuroprotective effects, among them, the modulation of oxidative biochemistry in plasma (by restoring GSH levels) and in the hippocampus (by reducing LPO levels and increasing antioxidant parameters) and cognitive function improvement. Therefore, physical exercise can be an important prophylactic and therapeutic tool in order to ameliorate and even prevent the deleterious effects of EtOH on cognitive functions.

Comparison of the effects of two antioxidant diets on oxidative stress markers in triathletes

Intense exercise generates an imbalance in the redox system. However, chronic exercise can yield antioxidant adaptations. A few studies with humans have investigated the effects of antioxidant diets on athletes. Therefore we compared the effects of two dietary interventions on oxidative stress in competitive triathletes. Thirteen male triathletes were selected and divided into 2 groups: one that had a regular antioxidant diet (RE-diet) and the other that had a high antioxidant diet (AO-diet). The diet period was 14 days and blood samples were collected before and after this period. The AO-diet provided twice the dietary reference intake (DRI) of α-tocopherol (30 mg), five times the DRI of ascorbic acid (450 mg), and twice the DRI of vitamin A (1800 g), while the RE-diet provided the DRI of α-tocopherol (15 mg), twice the DRI of ascorbic acid (180 mg) and the DRI of vitamin A (900 μg). The oxidative stress parameters evaluated were: thiobarbituric acid reactive substances (TBARS), total reactive antioxidant potential (TRAP), total sulfhydryl, carbonyl, superoxide dismutase (SOD) activity, hydrogen peroxide consumption and glutathione peroxidase (GPx) activity. We observed, after the diet period, an increase in sulfhydryl, TRAP, TBARS and SOD activity, and a decrease in carbonyl levels. However, no changes were found in hydrogen peroxide consumption or GPx activity. We concluded that antioxidant-enriched diets can improve the redox status of triathletes.

Acute Low-Volume High-Intensity Interval Exercise and Continuous Moderate-Intensity Exercise Elicit a Similar Improvement in 24-h Glycemic Control in Overweight and Obese Adults

Background: Acute exercise reduces postprandial oxidative stress and glycemia; however, the effects of exercise intensity are unclear. We investigated the effect of acute low-volume high-intensity interval-exercise (LV-HIIE) and continuous moderate-intensity exercise (CMIE) on glycemic control and oxidative stress in overweight and obese, inactive adults.

Methods: Twenty-seven adults were randomly allocated to perform a single session of LV-HIIE (9 females, 5 males; age: 30 ± 1 years; BMI: 29 ± 1 kg·m⁻²; mean ± SEM) or CMIE (8 females, 5 males; age: 30 ± 2.0; BMI: 30 ± 2.0) 1 h after consumption of a standard breakfast. Plasma redox status, glucose and insulin were measured. Continuous glucose monitoring (CGM) was conducted during the 24-h period before (rest day) and after exercise (exercise day).

Results: Plasma thiobarbituric acid reactive substances (TBARS; 29 ±13%, p < 0.01; mean percent change ±90% confidence limit), hydrogen peroxide (44 ± 16%, p < 0.01), catalase activity (50 ± 16%, p < 0.01), and superoxide dismutase activity (21 ± 6%, p < 0.01) significantly increased 1 h after breakfast (prior to exercise) compared to baseline. Exercise significantly decreased postprandial glycaemia in whole blood (−6 ± 5%, p < 0.01), irrespective of the exercise protocol. Only CMIE significantly decreased postprandial TBARS (CMIE: −33 ± 8%, p < 0.01; LV-HIIE: 11 ± 22%, p = 0.34) and hydrogen peroxide (CMIE: −25 ± 15%, p = 0.04; LV-HIIE: 7 ± 26%; p = 0.37). Acute exercise provided a similar significant improvement in 24-h average glucose levels (−5 ± 2%, p < 0.01), hyperglycemic excursions (−37 ± 60%, p < 0.01), peak glucose concentrations (−8 ± 4%, p < 0.01), and the 2-h postprandial glucose response to dinner (−9 ± 4%, p < 0.01), irrespective of the exercise protocol.

Conclusion: Despite elevated postprandial oxidative stress compared to CMIE, LV-HIIE is an equally effective exercise mode for improving 24-h glycemic control in overweight and obese adults.

Altered extracellular ATP, ADP, and AMP hydrolysis in blood serum of sedentary individuals after an acute, aerobic, moderate exercise session

Nucleotidases participate in the regulation of physiological and pathological events, such as inflammation and coagulation. Exercise promotes distinct adaptations, and can influence purinergic signaling. In the present study, we investigated soluble nucleotidase activities in the blood serum of sedentary young male adults at pre- and post-acute moderate aerobic exercise. In addition, we evaluated how this kind of exercise could influence adenine nucleotide concentrations in the blood serum. Sedentary individuals were submitted to moderate aerobic exercise on a treadmill; blood samples were collected pre- and post-exercise, and serum was separated for analysis. Results showed increases in ATP, ADP, and AMP hydrolysis post-exercise, compared to pre-exercise values. The ecto-nucleotide pyrophosphatase/phosphodiesterase was also evaluated, showing an increased activity post-exercise, compared to pre-exercise. Purine levels were analyzed by HPLC in the blood serum, pre- and post-exercise. Decreased levels of ATP and ADP were found post-exercise, in contrast with pre-exercise values. Conversely, post-exercise levels of adenosine and inosine increased compared to pre-exercise levels. Our results indicate an influence of acute exercise on ATP metabolism, modifying enzymatic behavior to promote a protective biological environment.

Acute High-Intensity Interval Exercise-Induced Redox Signaling Is Associated with Enhanced Insulin Sensitivity in Obese Middle-Aged Men

Background: Obesity and aging are associated with increased oxidative stress, activation of stress and mitogen activated protein kinases (SAPK), and the development of insulin resistance and metabolic disease. In contrast, acute exercise also increases oxidative stress and SAPK signaling, yet is reported to enhance insulin sensitivity and reduce the risk of metabolic disease. This study explored this paradox by investigating the effect of a single session of high-intensity interval-exercise (HIIE) on redox status, muscle SAPK and insulin protein signaling in eleven middle-aged obese men.

Methods: Participants completed a 2 h hyperinsulinaemic-euglycaemic clamp at rest, and 60 min after HIIE (4 × 4 mins at 95% HR_peak; 2 min recovery periods), separated by 1–3 weeks.

Results: Irrespective of exercise-induced changes to redox status, insulin stimulation both at rest and after HIIE similarly increased plasma superoxide dismutase activity, plasma catalase activity, and skeletal muscle 4-HNE; and significantly decreased plasma TBARS and hydrogen peroxide. The SAPK signaling pathways of p38 MAPK, NF-κB p65, and JNK, and the distal insulin signaling protein AS160^Ser588, were activated with insulin stimulation at rest and to a greater extent with insulin stimulation after a prior bout of HIIE. Higher insulin sensitivity after HIIE was associated with higher insulin-stimulated SOD activity, JNK, p38 MAPK and NF-κB phosphorylation (r = 0.63, r = 0.71, r = 0.72, r = 0.71; p < 0.05, respectively).

Conclusion:These findings support a role for redox homeostasis and SAPK signaling in insulin-stimulated glucose uptake which may contribute to the enhancement of insulin sensitivity in obese men 3 h after HIIE.

Effect of Maximal Versus Supra-Maximal Exhausting Race on Lipid Peroxidation, Antioxidant Activity and Muscle-Damage Biomarkers in Long-Distance and Middle-Distance Runners

Background

Exhausting physical exercise increases lipid peroxidation and causes important muscle damages. The human body tries to mitigate these adverse effects by mobilizing its antioxidant defenses.

Objectives

This study aims to investigate the effect of a maximal versus supra-maximal race sustained until exhaustion on lipid peroxidation, antioxidant activity and muscle-damage biomarkers in trained (i.e. long-distance and middle-distance runners) and sedentary subjects.

Materials and Methods

The study has been carried out on 8 middle-distance runners (MDR), 9 long-distance runners (LDR), and 8 sedentary subjects (SS). Each subject has undergone two exhaustive running tests, the first one is an incremental event (VAMEVAL test), the second one is a constant supra-maximal intensity test (limited-time test). Blood samples were collected at rest and immediately after each test.

Results

A significant increase in malondialdehyde (MDA) concentrations was observed in SS and MDR after the VAMEVAL test and in LDR after the Limited-Time test. A significant difference was also observed between LDR and the other two groups after the VAMEVAL test, and between LDR and MDR after the Limited-Time test. Significant modifications, notably, in myoglobin, CK, LDH, IL-6, TNF-α, and TAS were likewise noted but depending on the race-type and the sportive specialty.

Conclusions

Maximal and supra-maximal races induce a significant increase in lipid peroxidation and cause non-negligible inflammation and muscle damage. These effects were relatively related to the physical exercise type and the sportive specialty.

Iron Metabolism in Field Hockey Players During an Annual Training Cycle

Post-physical training changes in iron metabolism in the human body often occur. To fully describe these processes, fifteen male Polish National Team field hockey players (age 27.7 ± 5.2 years, body mass 72.8 ± 7.6 kg and body height 177.1 ± 5.7 cm) were examined in three phases of an annual training cycle: preparatory (T1), competitive (T2) and transition (T3). To assess aerobic fitness, maximal oxygen uptake (VO₂max) was evaluated. Based on the iron concentration, the changes in total iron binding capacity (TIBC), unsaturated iron binding capacity (UIBC) and other selected haematological indicators (haemoglobin, erythrocytes, mean corpuscular haemoglobin - MCH) in iron metabolism were estimated. The average values of maximum oxygen uptake increased from 54.97 ± 3.62 ml·kg⁻¹·min⁻¹ in T1 to 59.93 ± 3.55 ml·kg⁻¹·min⁻¹ in T2 (p<0.05) and then decreased to 56.21 ± 4.56 ml·kg⁻¹·min⁻¹ in T3 (p<0.05). No statistically significant changes in the erythrocyte count were noted. The MCH and haemoglobin concentration decreased between T1 and T2. The maximal exercise test caused a significant (p<0.05) increase in the plasma iron concentration during the competition and transition phases. Progressive but non-significant increases in resting iron concentration, TIBC and UIBC in the analysed annual training cycle were noted. To show global changes in iron metabolism in the human body, it is necessary to determine additional variables, i.e. UIBC, TIBC, haemoglobin, MCH or the erythrocyte count. The direction of changes in iron metabolism depends on both the duration and intensity of the physical activity and the fitness level of the subjects. Dietary intake of iron increases the level of this trace element and prevents anaemia associated with training overloads.

Exercise is the real polypill

The concept of a "polypill" is receiving growing attention to prevent cardiovascular disease. Yet similar if not overall higher benefits are achievable with regular exercise, a drug-free intervention for which our genome has been haped over evolution. Compared with drugs, exercise is available at low cost and relatively free of adverse effects. We summarize epidemiological evidence on the preventive/therapeutic benefits of exercise and on the main biological mediators involved.

Effects of dietary extra-virgin olive oil on oxidative stress resulting from exhaustive exercise in rat skeletal muscle: a morphological study

Physical exercise induces oxidative stress through production of reactive oxygen species and can cause damage to muscle tissue. Oxidative stress, resulting from exhaustive exercise is high and improvement of antioxidant defenses of the body may ameliorate damage caused by free radicals. Extra-virgin olive oil is widely considered to possess anti-oxidative properties. The aim of this study was to determine if extra-virgin olive oil improved the adaptive responses in conditions of oxidative stress. Twenty-four 12-week-old male Sprague-Dawley rats were divided in three groups: (1) rats fed with standard chow and not subjected to physical exercise; (2) rats fed with standard chow and subjected to exhaustive exercise; (3) rats fed with a diet rich in oleic acid, the major component of extra-virgin olive oil, and subjected to exhaustive exercise. Exhaustive exercise consisted of forced running in a five-lane 10° inclined treadmill at a speed of 30 m/min for 70-75 min. We studied some biomarkers of oxidative stress and of antioxidant defenses, histology and ultrastructure of the Quadriceps femoris muscle (Rectus femoris). We observed that, in rats of group 3, parameters indicating oxidative stress such as hydroperoxides and thiobarbituric acid-reactive substances decreased, parameters indicating antioxidant defenses of the body such as non-enzymatic antioxidant capacity and Hsp70 expression increased, and R. femoris muscle did not show histological and ultrastructural alterations. Results of this study support the view that extra-virgin olive oil can improve the adaptive response of the body in conditions of oxidative stress.

Comparison of the short-term oxidative stress response in National League basketball and soccer adolescent athletes

Physical exercise is considered protective against oxidative stress-related disorders. However, there is increasing evidence that strenuous activity may induce increased oxidative stress response. This study investigated the impact of vigorous physical activity on serum oxidative stress markers in 36 soccer and 12 basketball National League adolescent athletes 40 minutes before and 15 minutes after a National League game. Serum total peroxide, fibrinogen, polymorphonuclear (PMN) elastase, and myeloperoxidase levels were determined. No significant differences in any of the measured parameters were observed before the match. Soccer players exhibited significantly lower total peroxide (P < .05) and higher PMN elastase concentrations (P < .05) than that of the basketball athletes after the game. A number of important differences between these 2 sports, such as duration or total aerobic and anaerobic demands, may affect oxidative status. These parameters need to be further examined in order to elucidate the different effects of these 2 sports on postexercise oxidative status.

Effect of exercise on plasma paraoxonase1 activity in rugby players: dependance on training experience

OBJECTIVES

There are conflicting data on the influence of physical activity on paraoxonase1 (PON1) activity. The purpose of this study is to investigate the effect of maximal exercise (ME) on plasma paraoxonase (PON) and arylesterase (ARE) activity in elite rugby players. In addition, the influence of training experience and PON1 Q192R polymorphism on PON1 activity changes at ME was evaluated.

METHODS

Twenty-five elite rugby players ages 22.0±3.71 years, consisting of 11 juniors--J (2-7 years of training) and 14 seniors--S (8-15 years of training), completed ME on a cycle ergometer. PON and ARE activity, ferric reducing activity of plasma (FRAP), uric acid (UA), and total bilirubin concentration, as well as thiobarbituric acid reactive substances and lipid profile were investigated in the plasma before, at the bout, and 30 minutes after ME.

RESULTS

At the bout of ME we found an increase in PON1 activities, ARE/high-density lipoprotein C ratio, TBil, and TChol. However, ARE activity changes were not observed in the group of rugby players training for ≤7 years. FRAP and UA increased later--30 minutes after ME.

CONCLUSION

We conclude that in rugby players PON1 changes during ME depend on age, body composition, and training experience. The influence of PON1 Q192R polymorphism on PON1 changes at ME remains debatable.

The exercise dose affects oxidative stress and brachial artery flow-mediated dilation in trained men

The aim of this investigation was to establish whether changes in oxidative stress and endothelial function following acute aerobic exercise are dose-dependent. Ten healthy trained men completed four exercise sessions: 50% VO(2peak) for 30 min (moderate intensity moderate duration, MIMD), 50% VO(2peak) for 60 min (moderate intensity long duration, MILD), 80% VO(2peak) for 30 min (high intensity moderate duration, HIMD), and 80% VO(2peak) for the time to reach the caloric equivalent of MIMD (high intensity short duration, HISD). Thiobarbituric acid reactive substances (TBARS) were measured as an index of oxidative stress and brachial artery flow-mediated dilation (FMD) was assessed as an index of endothelial function. Variables were measured at baseline, immediately post-exercise, 1 and 2 h post-exercise. Both HIMD (14.2 ± 2.5 μmol/L) and HISD (14.7 ± 1.9 μmol/L) TBARS differed from MIMD (11.8 ± 1.5 μmol/L) immediately post-exercise. TBARS increased from pre to immediately post-exercise for HIMD (12.6 ± 2.1 vs.14.2 ± 2.5 μmol/L) and HISD (12.3 ± 2.8 vs. 14.7 ± 1.9 μmol/L). Both MIMD (7.2 ± 2.2%) and HISD (7.6 ± 2.7%) FMD immediately post-exercise were greater than HIMD (4.7 ± 2.2%). An increase of FMD from pre to immediately post-exercise was found for MIMD (5.0 ± 2.5 vs. 7.2 ± 2.2%) and HISD (5.9 ± 2.4 vs. 7.6 ± 2.7%). These data suggest that acute exercise-induced TBARS are exercise intensity-dependent whereas FMD appears to improve following energy expenditure equivalent to 30 min 50% VO(2peak), regardless of intensity or duration.

Exercise training, NADPH oxidase p22phox gene polymorphisms, and hypertension

INTRODUCTION

Oxidative stress that is mediated through NADPH oxidase activity plays a role in the pathology of hypertension, and aerobic exercise training reduces NADPH oxidase activity. The involvement of genetic variation in the p22phox (CYBA) subunit genes in individual oxidative stress responses to aerobic exercise training has yet to be examined in Pre and Stage 1 hypertensives.

METHODS

Ninety-four sedentary Pre and Stage 1 hypertensive adults underwent 6 months of aerobic exercise training at a level of 70% VO2max to determine whether the CYBA polymorphisms, C242T and A640G, were associated with changes in urinary 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha), urinary nitric oxide metabolites (NOx), and plasma total antioxidant capacity (TAC).

RESULTS

Demographic and subject characteristics were similar among genotype groups for both polymorphisms. At baseline, a significant (P = 0.03) difference among the C2424T genotype groups in 8-iso-PGF2alpha levels was detected, with the TT homozygotes having the lowest levels and the CC homozygotes having the highest levels. However, no differences were found at baseline between the A640G genotype groups. After 6 months of aerobic exercise training, there was a significant increase in VO2max (P < 0.0001) in the entire study population. In addition, there were significant increases in both urinary 8-iso-PGF2alpha (P = 0.002) and plasma TAC (P=0.03) levels and a significant decrease in endogenous urinary NOx (P < 0.0001). Overall, aerobic exercise training elicited no significant differences among genotype groups in either CYBA variant for any of the oxidative stress variables.

CONCLUSIONS

We found that compared with CYBA polymorphisms C242T and A640G, it was aerobic exercise training that had the greatest influence on the selected biomarkers; furthermore, our results suggest that the C242T CYBA variant influences baseline levels of urinary 8-iso-PGF2alpha but not the aerobic exercise-induced responses.

Effects of supplementation with free glutamine and the dipeptide alanyl-glutamine on parameters of muscle damage and inflammation in rats submitted to prolonged exercise

In this study, we investigated the effect of the supplementation with the dipeptide L-alanyl-L-glutamine (DIP) and a solution containing L-glutamine and L-alanine on plasma levels markers of muscle damage and levels of pro-inflammatory cytokines and glutamine metabolism in rats submitted to prolonged exercise. Rats were submitted to sessions of swim training for 6 weeks. Twenty-one days prior to euthanasia, the animals were supplemented with DIP (n = 8) (1.5 g.kg(-1)), a solution of free L-glutamine (1 g.kg(-1)) and free L-alanine (0.61 g.kg(-1)) (G&A, n = 8) or water (control (CON), n = 8). Animals were killed at rest before (R), after prolonged exercise (PE-2 h of exercise). Plasma concentrations of glutamine, glutamate, tumour necrosis factor-alpha (TNF-alpha), prostaglandin E2 (PGE2) and activity of creatine kinase (CK), lactate dehydrogenase (LDH) and muscle concentrations of glutamine and glutamate were measured. The concentrations of plasma TNF-alpha, PGE2 and the activity of CK were lower in the G&A-R and DIP-R groups, compared to the CON-R. Glutamine in plasma (p < 0.04) and soleus muscle (p < 0.001) was higher in the DIP-R and G&A-R groups relative to the CON-R group. G&A-PE and DIP-PE groups exhibited lower concentrations of plasma PGE2 (p < 0.05) and TNF-alpha (p < 0.05), and higher concentrations of glutamine and glutamate in soleus (p < 0.001) and gastrocnemius muscles (p < 0.05) relative to the CON-PE group. We concluded that supplementation with free L-glutamine and the dipeptide LL-alanyl-LL-glutamine represents an effective source of glutamine, which may attenuate inflammation biomarkers after periods of training and plasma levels of CK and the inflammatory response induced by prolonged exercise.

DNA damage after long-term repetitive hyperbaric oxygen exposure

A single exposure to hyperbaric oxygen (HBO), i.e., pure oxygen breathing at supra-atmospheric pressures, causes oxidative DNA damage in humans in vivo as well as in isolated lymphocytes of human volunteers. These DNA lesions, however, are rapidly repaired, and an adaptive protection is triggered against further oxidative stress caused by HBO exposure. Therefore, we tested the hypothesis that long-term repetitive exposure to HBO would modify the degree of DNA damage. Combat swimmers and underwater demolition team divers were investigated because their diving practice comprises repetitive long-term exposure to HBO over years. Nondiving volunteers with and without endurance training served as controls. In addition to the measurement of DNA damage in peripheral blood (comet assay), blood antioxidant enzyme activities, and the ratio of oxidized and reduced glutathione content, we assessed the DNA damage and superoxide anion radical (O2•−) production induced by a single ex vivo HBO exposure of isolated lymphocytes. All parameters of oxidative stress and antioxidative capacity in vivo were comparable in the four different groups. Exposure to HBO increased both the level of DNA damage and O2•− production in lymphocytes, and this response was significantly more pronounced in the cells obtained from the combat swimmers than in all the other groups. However, in all groups, DNA damage was completely removed within 1 h. We conclude that, at least in healthy volunteers with endurance training, long-term repetitive exposure to HBO does not modify the basal blood antioxidant capacity or the basal level of DNA strand breaks. The increased ex vivo HBO-related DNA damage in isolated lymphocytes from these subjects, however, may reflect enhanced susceptibility to oxidative DNA damage.

Níveis de beta-endorfina em resposta ao exercício e no sobretreinamento

O sobretreinamento (ST) é um fenômeno esportivo complexo e multifatorial; e atualmente não existe nenhum marcador independente que possa diagnosticá-lo. Interessantemente, alguns sintomas do ST apresentam relação com os efeitos da b-endorfina (b-end1-31). Alguns de seus efeitos são importantes para o treinamento, como analgesia, maior tolerância ao lactato e euforia do exercício. Esses efeitos podem ser revertidos por destreinamento ou por ST, ocasionando diminuição no desempenho, redução da tolerância à carga e depressão. O exercício físico é o principal estímulo da b-end1-31, pois sua secreção é volume/intensidade dependente, tanto para exercícios aeróbios quanto anaeróbios. No entanto, o treinamento excessivo pode diminuir suas concentrações, alterando assim seus efeitos benéficos para o treinamento. Portanto, a b-end1-31 poderia ser utilizada como um marcador adicional de ST, principalmente porque seus efeitos apresentam extensa relação com os sintomas do ST.

Age and natural metabolically-intensive behavior affect oxidative stress and antioxidant mechanisms

Flying honey bees have among the highest mass-specific metabolic rates ever measured, suggesting that their flight muscles may experience high levels of oxidative stress during normal daily activities. We measured parameters of oxidative stress and antioxidant capacity in highly metabolic flight muscle and less active head tissue in cohorts of age-matched nurse bees, which rarely fly, and foragers, which fly several hours per a day. Naturally occurring foraging flight elicited an increase in flight muscle Hsp70 content in both young and old foragers; however catalase and total antioxidant capacity increased only in young flight muscle. Surprisingly, young nurse bees also showed a modest daily increase in Hsp70, catalase levels and antioxidant capacity, and these effects were likely due to collecting the young nurses soon after orientation flights. There were no differences in flight muscle carbonyl content over the course of daily activity and few differences in Hsp70, catalase, total antioxidant capacity and protein carbonyl levels in head tissue regardless of age or activity. In summary, honey bee flight likely produces high levels of reactive oxygen species in flight muscle that, when coupled with age-related decreases in antioxidant activity may be responsible for behavioral senescence and reduced longevity.

Aspectos atuais sobre estresse oxidativo, exercícios físicos e suplementação

As espécies reativas de oxigênio (ERO) são normalmente produzidas pelo metabolismo corporal. Todavia, ERO apresentam a capacidade de retirar elétrons de outros compostos celulares, sendo capazes de provocar lesões oxidativas em várias moléculas, fato que leva à perda total da função celular. A realização de exercícios físicos aumenta a síntese de ERO, além de promover lesão muscular e inflamação. Após uma sessão de exercícios físicos, inicia-se normalmente a fase de recuperação, quando são observados diversos efeitos positivos à saúde, incluindo o aumento da resistência a novas lesões induzidas ou não por exercícios, fato que é considerado como um processo "adaptativo". Diversos estudos, porém, relatam que essa recuperação não é alcançada por indivíduos que se submetem a exercícios intensos e prolongados, ou, ainda, que possuem elevada freqüência de treinamento. Alternativas nutricionais têm sido muito estudadas, a fim de reduzir os efeitos promovidos pelo exercício extenuante, dentre as quais está a suplementação com vitamina E, vitamina C, creatina e glutamina. Esta revisão tem como objetivo abordar os aspectos atuais envolvendo a formação das ERO, os processos de lesão celular e inflamação, a adaptação aos tipos de exercício aeróbio e anaeróbio e possíveis intervenções nutricionais.

Biochemical assessments of retinol, alpha-tocopherol, pyridoxal--5-phosphate oxidative stress index and total antioxidant status in adolescent professional basketball players and sedentary controls

Physical training is known to increase the antioxidant defence system and reduce exercise-induced oxidative stress. However, intense physical aerobic and anaerobic training with competition, such as those imposed on young professional basketball players can induce an increase of oxidative stress, which can be implicated with overtraining. The aim of this study was to test the effect of training and competition load on oxidative stress, antioxidant status, and vitamin levels in basketball players. Oxidative Stres Index (OSI 1), Total Peroxide (TPx) antioxidant (vitamin E, A and The total antioxidant status (TAC 1)), biochemical lipid parameters, as well as training results were measured. Results showed that all plasma vitamin levels were significantly higher in basketball players (vitamin A: 1.61 +/- 0.05 mmol/l, vitamin E: 26.45 +/- 0.72 mmol/l, vitamin B6: 10.58 +/- 0.7 mgr/l) than sedentary controls (vitamin A: 1.22 +/- 0.04 mmol /l, vitamin E: 19.24 +/- 0.73 mmol/l, vitamin B6: 6.0 +/- 0.35 mgr/l) (p < 0.01). In addition TAC 1 was 2.06 +/- 0.02 and 1.89 +/- 0.01 mmol Trolox eq/L in basketball players and controls, respectively (p < 0.01). Conversely OSI was 0.89 +/- 0.09 arbitrary unit and 0.88 +/- 0.071 arbitrary unit in basketball players and controls, respectively (p > 0.05). However, total plasma peroxide level (TPx) of basketball players and controls was not statistically different (18.55 +/- 2.07 and 17.18 +/- 1.61 micromol H2O2/L, respectively; p > 0.05). We conclude that physical exercise increase antioxidant levels and cause balance of the homeostasis. Training can not have positive or negative effects on oxidative stress depending on training load. The results suggested that oxidative stress and antioxidant measurement are significant in the biological follow-up of young basketball players.

O estresse oxidativo e o exercício físico em indivíduos HIV positivo

A infecção pelo vírus da imunodeficiência humana (HIV) é acompanhada por alterações estruturais e funcionais relacionadas ao sistema imunológico. Além disso, o aumento do estresse oxidativo (EO) nos portadores do HIV, caracterizado por diminuição nos níveis de glutationa (GSH), aumentos na glutationa oxidada (GSSG), na razão GSSG/GSH e lipoperoxidação, bem como redução da atividade de enzimas antioxidantes - catalase, superóxido dismutase (SOD) e glutationa peroxidase (GPx) - é uma conseqüência da evolução dos pacientes infectados com HIV. As células do sistema imunológico necessitam de altas concentrações de antioxidantes para manter o balanço redox e preservar a sua integridade e função. Quando ocorre a depleção dos antioxidantes, há diminuição da resposta imunológica e aumento na replicação do HIV. O uso da terapia anti-retroviral combinada (TARV) melhorou significativamente a evolução clínica dos pacientes, porém, mesmo assim, alguns continuam apresentando EO aumentado e outros efeitos da TARV, como alterações no metabolismo lipídico e muscular. O treinamento físico é utilizado como intervenção não farmacológica nos pacientes infectados pelo HIV para proporcionar melhoria nos parâmetros antropométricos, aeróbios, musculares e psicológicos, porém, há carência de estudos sobre a sua utilização em relação ao estresse oxidativo. Nesta revisão, foram analisados os tópicos referentes ao estresse oxidativo nos pacientes HIV positivos e os possíveis benefícios do exercício físico na capacidade antioxidante. O treinamento físico é uma estratégia auxiliar para os pacientes, com ou sem uso da TARV, uma vez que melhora os aspectos cardiorrespiratórios, musculares, antropométricos e psicológicos sem induzir a imunossupressão. Referindo-se ao estresse oxidativo, infere-se, a partir dos dados em indivíduos HIV negativos, que o treinamento físico pode gerar adaptações que minimizam os efeitos deletérios provocados pelo EO através de melhorias nos níveis das defesas antioxidantes enzimáticas e não enzimáticas.

Sobretreinamento: teorias, diagnóstico e marcadores

O objetivo do treinamento esportivo é o aumento e a melhora do desempenho físico. Quando a intensidade, a duração e a carga de trabalho diário dos exercícios são apropriadas, adaptações fisiológicas positivas ocorrem. Entretanto, existe uma linha muito tênue entre um ótimo desempenho e uma diminuição do mesmo em função do sobretreinamento. O sobretreinamento pode incluir lesão e fraqueza muscular, ativação das citosinas, mudanças hormonais e hematológicas, alterações no humor, depressão psicológica e problemas nutricionais que podem causar diminuição do apetite e diarréia. Muitos estudos sobre o sobretreinamento foram realizados num esforço de identificar suas causas, seus sintomas, hipóteses e marcadores que pudessem identificá-lo, mas este diagnóstico é muito difícil, pois os sintomas do sobretreinamento se confundem com os do pré-sobretreinamento e com os do treinamento normal, sendo que é difícil dissociá-los. No momento não existe um simples marcador que possa prever o sobretreinamento; dessa forma, a diminuição no desempenho físico ainda é considerada o padrão-ouro. Marcadores hormonais, bioquímicos, imunes, psicológicos e o estresse oxidativo podem dar informações relevantes para um diagnóstico preciso e confiável para o sobretreinamento.