Edith Filaire

Oxidative stress : relationship with exercise and training.

Free radicals are reactive compounds that are naturally produced in the human body. They can exert positive effects (e.g. on the immune system) or negative effects (e.g. lipids, proteins or DNA oxidation). To limit these harmful effects, an organism requires complex protection — the antioxidant system. This system consists of antioxidant enzymes (catalase, glutathione peroxidase, superoxide dismutase) and non-enzymatic antioxidants (e.g. vitamin E [tocopherol], vitamin A [retinol], vitamin C [ascorbic acid], glutathione and uric acid). An imbalance between free radical production and antioxidant defence leads to an oxidative stress state, which may be involved in aging processes and even in some pathology (e.g. cancer and Parkinson’s disease). Physical exercise also increases oxidative stress and causes disruptions of the homeostasis. Training can have positive or negative effects on oxidative stress depending on training load, training specificity and the basal level of training. Moreover, oxidative stress seems to be involved in muscular fatigue and may lead to overtraining.

Psychophysiological stress in tennis players during the first single match of a tournament.

The purpose of this investigation was to study the physiological and psychological states of 16 tennis players (8 males, 8 females) during the day of the first match of a tennis tournament and their relation to performance. Athletes completed the Competitive State Anxiety Inventory-2, including both intensity and direction subscales prior to the first match and collected saliva for cortisol analysis on several occasions: during a resting day (baseline values) and prior to and after both competitions. Results showed the males and females have different responses in the CSAI-2 subcomponents. Somatic anxiety was significantly higher (+23%: p<.05) in females compared to males whereas self-confidence was significantly higher in males (+34%: p<.05). Winners had significantly lower cognitive anxiety and higher Self-confidence scores than losers. Somatic anxiety was significantly higher in the losers. Our results showed a cortisol response to competition, which was especially characterized by an anticipatory rise. Males had the same pattern of cortisol responses than females, even if the cortisol concentrations were significantly higher in females the day of the competition. According to the outcome, significant differences between winners and losers cortisol concentrations were observed whatever the hour of taking (except in the evening), cortisol concentrations being the highest at the losers. The measurement of cortisol at the same time that self-report psychological indicators would provide an approach to examine changes in anxiety, and its relationship to performance.

Effect of a Probiotics Supplementation on Respiratory Infections and Immune and Hormonal Parameters during Intense Military Training

This study examined the effect of a probiotics supplementation on respiratory tract infection (RTI) and immune and hormonal changes during the French Commando training (3-week training followed by a 5-day combat course). Cadets (21 +/- 0.4 years) received either a probiotics (n = 24) or a placebo (n = 23) supplementation over the training period. We found no difference in the RTI incidence between groups but a significantly greater proportion of rhinopharyngitis in the probiotic group (p < 0.05). Among immune parameters, the major finding was an immunoglobulin A decrease after the combat course only in the placebo group (p < 0.01), but the difference between the two groups was not significant. A greater increase in dehydroepiandrostane sulfate was observed in the probiotics group after the combat course (p < 0.05). This study suggested that the benefits of a probiotics supplementation in a multistressor environment relied mainly on its capacity to prevent the infection to spread throughout the respiratory tract.

Lung cancer: What are the links with oxidative stress, physical activity and nutrition

Oxidative stress appears to play an essential role as a secondary messenger in the normal regulation of a variety of physiological processes, such as apoptosis, survival, and proliferative signaling pathways. Oxidative stress also plays important roles in the pathogenesis of many diseases, including aging, degenerative disease, and cancer. Among cancers, lung cancer is the leading cause of cancer in the Western world. Lung cancer is the commonest fatal cancer whose risk is dependent on the number of cigarettes smoked per day as well as the number of years smoking, some components of cigarette smoke inducing oxidative stress by transmitting or generating oxidative stress. It can be subdivided into two broad categories, small cell lung cancer and non-small-cell lung cancer, the latter is the most common type. Distinct measures of primary and secondary prevention have been investigated to reduce the risk of morbidity and mortality caused by lung cancer. Among them, it seems that physical activity and nutrition have some beneficial effects. However, physical activity can have different influences on carcinogenesis, depending on energy supply, strength and frequency of exercise loads as well as the degree of exercise-mediated oxidative stress. Micronutrient supplementation seems to have a positive impact in lung surgery, particularly as an antioxidant, even if the role of micronutrients in lung cancer remains controversial. The purpose of this review is to examine lung cancer in relation to oxidative stress, physical activity, and nutrition.

Reactive oxygen species and exercise on bone metabolism: Friend or enemy?

Reactive oxygen species (ROS) are well recognised for playing a dual role as both deleterious and beneficial species. They are normally generated by tightly regulated enzymes. ROS overproduction arises either from mitochondrial electron transport chain or excessive stimulation of NAD(P)H resulting in oxidative stress, a deleterious process that can be an important mediator of damage to cell structures (lipids, membranes, proteins, and DNA). However, ROS could have a beneficial affect at low/moderate concentrations. Physiological roles in cellular responses to noxia have been reported, in defence against infectious agents, in the function of a number of cellular signalling pathways, and the induction of a mitogenic response. The role of ROS in bone metabolism is dual. It is a key modulator of bone cell function and also implicated in the pathophysiology of mineral tissues. Elevated production of ROS and/or depletion of antioxidants have also been observed in a variety of pathological conditions, including inflammatory joint diseases. Performing physical exercise is associated with numerous health benefits, playing a role especially in the prevention of bone loss. However, the production of ROS increases during demanding exercise. To explore this further, the aim of the present review was to examine bone remodelling in relation to oxidative stress and exercise.

Disordered eating, perfectionism and body-esteem of elite synchronized swimmers

Abstract The aims of the present study were to determine the extent to which unhealthy compensatory behaviours are observed in synchronized swimmers, and to examine the relationships between perfectionism, body-esteem dimensions, and restrained eating. Thirty-three elite adolescent synchronized swimmers completed the Multidimensional Perfectionism Scale (MPS-H), the Body-Esteem Scale, the Dietary Restraint Scale, and a self-report questionnaire during their pre-competitive period. The participants reported that they perceived themselves to be overweight, that they used weight loss methods such as self-induced vomiting, fasting, and intensive exercise, and unhealthy weight control behaviours such as skipping meals. The swimmers attributed the pressure to lose weight to team-mates, coaches, and themselves. Results showed that self-oriented perfectionism was significantly associated with dietary restraint and that body-esteem weight satisfaction has a mediator role between self-oriented perfectionism and dietary restraint. Additional research is required to examine the thrust of these results and the effectiveness of interventions that help prevent disordered eating patterns.

Radical Oxygen Species, Exercise and Aging: An Update

It is now well established that reactive oxygen species (ROS) play a dual role as both deleterious and beneficial species. In fact, ROS act as secondary messengers in intracellular signalling cascades; however, they can also induce cellular senescence and apoptosis. Aging is an intricate phenomenon characterized by a progressive decline in physiological functions and an increase in mortality, which is often accompanied by many pathological diseases. ROS are involved in age-associated damage to macromolecules, and this may cause derangement in ROS-mediated cell signalling, resulting in stress and diseases. Moreover, the role of oxidative stress in age-related sarcopenia provides strong evidence for the important contribution of physical activity to limit this process. Regular physical activity is considered a preventive measure against oxidative stress–related diseases. The aim of this review is to summarize the currently available studies investigating the effects of chronic and/or acute physical exercise on the oxidative stress process in healthy elderly subjects. Although studies on oxidative stress and physical activity are limited, the available information shows that acute exercise increases ROS production and oxidative stress damage in older adults, whereas chronic exercise could protect elderly subjects from oxidative stress damage and reinforce their antioxidant defences. The available studies reveal that to promote beneficial effects of physical activity on oxidative stress, elderly subjects require moderate-intensity training rather than high-intensity exercise.

Diurnal patterns of salivary alpha-amylase and cortisol secretion in female adolescent tennis players after 16 weeks of training

We examined the effects of 16 weeks of training on diurnal pattern of salivary alpha-amylase (sAA), cortisol, and the ratio of sAA over cortisol (AOC) in 12 national adolescent female tennis players. Stress and recovery were also evaluated using the Recovery-Stress-Questionnaire for Athletes-RESTQ-Sport. Data were collected after a 2-week rest (January, W0), and 4 months after W0 (W16). Subjects collected five saliva samples throughout a day. While all participants displayed the previously shown decrease after awakening in adolescents at W0, they showed a rise in the alpha-amylase awakening response and a higher alpha-amylase activity output (p<0.01) at W16 compared to W0. For the daily rhythm of cortisol we found subjects having a low overall output of salivary cortisol (p<0.01) and a blunted response to awakening at W16. Furthermore, an increase in the ratio AOC at W16, and a negative correlation between this ratio and Sport-specific recovery score. Our findings offer support for the hypothesis that increase of training load during the study period induced asymmetry activation between the two stress systems, in relation to psychological alterations and performance decrease. These results provide encouragement to continue exploring the impact of training program using a psychobiological approach among young athletes in order to prevent fatigue and preserve the health of these athletes.

Evaluations of the Psychometric Properties of the Recovery-Stress Questionnaire for Athletes among a Sample of Young French Table Tennis Players

This study used confirmatory factor analyses (CFAs) among a sample of young French table tennis players to test: (a) original 19-factor structure, (b) 14-factor structure recently suggested in literature, and (c) hierarchical factor structure of the Recovery-Stress Questionnaire for Athletes (RESTQ–Sport). 148 table tennis players completed the RESTQ–Sport and other self-report questionnaires between one to five occasions with a delay of 1 mo. between each completion. Results of CFAs showed: (a) evidence for relative superiority of the original model in comparison to an alternative model recently proposed in literature, (b) a good fit of the data for the 67-item 17-factor model of the RESTQ–Sport, and (c) an acceptable fit of the data for the hierarchical model of the RESTQ–Sport. Correlations between RESTQ–Sport subscales and burnout and motivation subscales also provided evidence for criterion-related validity of the RESTQ–Sport. This study provided support for reliability and validity of the RESTQ–Sport.

Psychophysiological Stress Responses during Training and Competition in Young Female Competitive Tennis Players

This study sought to compare the psychophysiological stress responses during an actual competitive game and a training session in a group of high-level young female tennis players. 12 players were monitored during one match and a training day (i.e., simulated match play). Measurements included salivary cortisol (SC), the revised Competitive Sport Anxiety Inventory, heart rate (HR), and rate of perceived exertion (RPE). Match day elicited higher SC levels for losers at all points in time when compared to winners. All players showed significantly lower SC levels during training when compared to the match at all points in time except during the evening for winners. Winners of match and training situations had significantly higher self-confidence and lower cognitive anxiety and somatic anxiety scores than losers. Heart rate and RPE were significantly higher for losers only during the match (158.9±8.3 vs. 168±6.7 bpm; 12.9±1.2 vs. 15±0.8, for losers and winners, respectively). There were moderate to strong correlations between SC, self-confidence and anxiety scores, and match workload (i.e., HR and RPE) only during the match day. These results indicate that the interplay between psychophysiological responses, match workload and outcome was evident only under real competitive situations.