Inflammation and oxidative stress as common mechanisms of pulmonary, autonomic, and musculoskeletal dysfunction after spinal cord injury

One of the etiopathogenic factors frequently associated with generalized organ damage after spinal cord injury corresponds to the imbalance of the redox state and inflammation, particularly of the respiratory, autonomic, and musculoskeletal systems. Our goal in this review was to gain a better understanding of this phenomenon by reviewing both animal and human studies. At the respiratory level, the presence of tissue damage is notable in situations that require increased ventilation due to lower thoracic distensibility and alveolar inflammation caused by higher levels of leptin as a result of increased fatty tissue. Increased airway reactivity, due to loss of sympathetic innervation, and levels of nitric oxide in exhaled air that are similar to those seen in asthmatic patients have also been reported. In addition, the loss of autonomic control efficiency leads to an uncontrolled release of catecholamines and glucocorticoids that induce immunosuppression, as well as a predisposition to autoimmune reactions. Simultaneously, blood pressure regulation is altered with vascular damage and atherogenesis associated with oxidative damage. At the muscular level, chronically elevated levels of prooxidants and lipoperoxidation associated with myofibrillar atrophy are described, with no reduction or reversibility of this process through antioxidant supplementatio

Effects of Exercise Training under Hyperbaric Oxygen on Oxidative Stress Markers and Endurance Performance in Young Soccer Players: A Pilot Study

The aim of the present study was to determine the effects of three weeks of hyperbaric oxygen (HBO2) training on oxidative stress markers and endurance performance in young soccer players. Participants (18.6±1.6 years) were randomized into hyperbaric-hyperoxic (HH) training (n=6) and normobaric normoxic (NN) training (n=6) groups. Immediately before and after the 5th, 10th, and 15th training sessions, plasma oxidative stress markers (lipid hydroperoxides and uric acid), plasma antioxidant capacity (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid [TROLOX]), arterial blood gases, acid-base balance, bases excess (BE), and blood lactate analyses were performed. Before and after intervention, maximal oxygen uptake (VO2max) and peak power output (PPO) were determined. Neither HH nor NN experienced significant changes on oxidative stress markers or antioxidant capacity during intervention. VO2max and PPO were improved (moderate effect size) after HH training. The results suggest that HBO2 endurance training does not increase oxidative stress markers and improves endurance performance in young soccer players. Our findings warrant future investigation to corroborate that HBO2 endurance training could be a potential training approach for highly competitive young soccer players

Sex-differences in the oxygenation levels of intercostales and vastus lateralis muscles during incremental exercise

This study aimed to examine sex differences in oxygen saturation in respiratory (SmO2-m.intercostales) and locomotor muscles (SmO2-m.vastus lateralis) while performing physical exercise. Twenty-five (12 women) healthy and physically active participants were evaluated during an incremental test with a cycle ergometer, while ventilatory variables (lung ventilation [V ̇E], tidal volume [Vt], and respiratory rate [RR]) were acquired through the breath-by-breath method. SmO2 was acquired using the MOXY devices on the m.intercostales and m.vastus lateralis. A two-way ANOVA (sex × time) indicated that women showed a greater significant decrease of SmO2-m.intercostales, and men showed a greater significant decrease of SmO2-m.vastus lateralis. Additionally, women reached a higher level of ΔSmO2-m.intercostales normalized to V ̇E (L·min-1) (p<0.001), whereas men had a higher level of ΔSmO2-m.vastus lateralis normalized to peak workload-to-weight (watts·kg-1, PtW) (p=0.049), as confirmed by Student's t-test. During an incremental physical exercise, women experienced a greater cost of breathing, reflected by greater deoxygenation of the respiratory muscles, whereas men had a higher peripheral load, indicated by greater deoxygenation of the locomotor muscles

Determination of the respiratory compensation point by detecting changes in intercostal muscles oxygenation by using near-infrared spectroscopy

This study aimed to evaluate if the changes in oxygen saturation levels at intercostal muscles (SmO2-m.intercostales) assessed by near-infrared spectroscopy (NIRS) using a wearable device could determine the respiratory compensation point (RCP) during exercise. Fifteen healthy competitive triathletes (8 male; 29±6 years; height 167.6±25.6 cm; weight 69.2±9.4 kg; V ̇O2-máx 58.4±8.1 mL·kg-1·min-1) were evaluated in a cycle ergometer during the maximal oxygen-uptake test (V ̇O2-máx), while lung ventilation (V ̇E), power output (watts, W) and SmO2-m.intercostales were measured. RCP was determined by visual method (RCPvisual: changes at ventilatory equivalents (V ̇E·V ̇CO2-1, V ̇E·V ̇O2-1) and end-tidal respiratory pressure (PetO2, PetCO2) and NIRS method (RCPNIRS: breakpoint of fall in SmO2-m.intercostales). During exercise, SmO2-m.intercostales decreased continuously showing a higher decrease when V ̇E increased abruptly. A good agreement between methods used to determine RCP was found (visual vs NIRS) at %V ̇O2-máx, V ̇O2, V ̇E, and W (Bland-Altman test). Correlations were found to each parameters analyzed (r=0.854; r=0.865; r=0.981; and r=0,968; respectively. p<0.001 in all variables, Pearson test), with no differences (p<0.001 in all variables, t-student test) between methods used (RCPvisual and RCPNIRS). We concluded that changes at SmO2-m.intercostales measured by NIRS could adequately determine RCP in triathletes

Horse Racing as a Model to Study the Relationship between Air Pollutants and Physical Performance

This study proposes the theoretical principles for the selection of a sample of horse races to study the relationship between air pollutants and performance. These criteria were then applied to an original dataset comparing the correlations between these variables obtained in &ldquo;Handicap&rdquo; versus &ldquo;Conditional&rdquo; type races. Methods: The mean concentration of pollutants during the six hours prior to the race and the speed of the test were determined in 441 official races at a racecourse in Santiago, Chile, during the summer and winter months of 2012. Using layout, track condition and distance (1000, 1100 and 1200 m) as criteria, a homogeneous group of races (&ldquo;Handicap&rdquo;; n = 214) versus a heterogeneous group (&ldquo;Conditional&rdquo;; n = 95) were compared using simple correlations (Spearman&rsquo;s test). Results: Race speed was related to greater levels of PM10, PM2.5, NO2, NO and SO2 and it was positively related to O3, a trend that was observed in the 1000, 1100 m races and in the total &ldquo;Handicap&rdquo; group. Similar results were observed only in 1000 m for the &ldquo;Conditional&rdquo; group with lower Rho, except for PM10 and PM2.5. The total races of the conditional group showed lower Rho values and significant associations of the same trend for CO, NO2, NO and SO2. Conclusions: Horse races between 1000 and 1200 m of the &ldquo;Handicap&rdquo; type appear to be an interesting group to study the relationship between air pollutants and the performance of racehorses. In the future, our observations should be expanded to other distances and other types of races

Atmospheric Pollutants Affect Physical Performance: A Natural Experiment in Horse Racing Studied by Principal Component Analysis

The impact of some atmospheric pollutants (PM10, PM2.5, O3, NO2, NO, SO2, CO), humidity and temperature were studied on the performance of thoroughbred racehorses. The study included 162 official handicap races held in 2012 in Santiago de Chile, at distances of 1000, 1100 and 1200 m, on a track in good condition, with a layout that included a bend, during the summer and winter months. The environmental variables were measured at the time of the race and were obtained from a monitoring station located 470 m from the equestrian center. The environmental variables showed an autocorrelation of variables, so they were reduced using principal component analysis. Subsequently, the principal components were correlated with running speed using Pearson&rsquo;s method. Totals of 60.17 and 23.29% of the total variability of the data was explained by principal components 1 and 2 (PC1 and PC2), respectively. PC1 was mainly determined by NO, NO2, and CO (loadings~0.90) and secondarily by PM10, PM2.5, and SO2 (loadings~0.6), with which the data showed inverse associations, while with temperature and O3 it showed direct associations (loadings~0.7). In addition, this component correlated negatively with running speed (r = &minus;0.50), while PC2 was not associated with this variable. In conclusion, using the principal component analysis strategy, it was determined that running speed is affected by air pollutants

Atmospheric Pollutants Affect Physical Performance: A Natural Experiment in Horse Racing Studied by Principal Component Analysis

The impact of some atmospheric pollutants (PM10, PM2.5, O3, NO2, NO, SO2, CO), humidity and temperature were studied on the performance of thoroughbred racehorses. The study included 162 official handicap races held in 2012 in Santiago de Chile, at distances of 1000, 1100 and 1200 m, on a track in good condition, with a layout that included a bend, during the summer and winter months. The environmental variables were measured at the time of the race and were obtained from a monitoring station located 470 m from the equestrian center. The environmental variables showed an autocorrelation of variables, so they were reduced using principal component analysis. Subsequently, the principal components were correlated with running speed using Pearson’s method. Totals of 60.17 and 23.29% of the total variability of the data was explained by principal components 1 and 2 (PC1 and PC2), respectively. PC1 was mainly determined by NO, NO2, and CO (loadings~0.90) and secondarily by PM10, PM2.5, and SO2 (loadings~0.6), with which the data showed inverse associations, while with temperature and O3 it showed direct associations (loadings~0.7). In addition, this component correlated negatively with running speed (r = −0.50), while PC2 was not associated with this variable. In conclusion, using the principal component analysis strategy, it was determined that running speed is affected by air pollutants

Saxitoxin Group Toxins Accumulation Induces Antioxidant Responses in Tissues of Mytilus chilensis, Ameghinomya antiqua, and Concholepas concholepas during a Bloom of Alexandrium pacificum

Saxitoxin (STX) group toxins consist of a set of analogues which are produced by harmful algal blooms (HABs). During a HAB, filter-feeding marine organisms accumulate the dinoflagellates and concentrate the toxins in the tissues. In this study, we analyze the changes in antioxidant enzymes and oxidative damage in the bivalves Mytilus chilensis and Ameghinomya antiqua, and the gastropod Concholepas concholepas during a bloom of Alexandrium pacificum. The results show that during the exponential phase of the bloom bivalves show an increase in toxicity and activity of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, and glutathinoe reductase, p &lt; 0.05), while in the gastropods, increased activity of antioxidant enzymes was associated with the bioaccumulation of toxins through the diet. At the end of the bloom, decreased activity of antioxidant enzymes in the visceral and non-visceral tissues was detected in the bivalves, with an increase in oxidative damage (p &lt; 0.05), in which the latter is correlated with the detection of the most toxic analogues of the STX-group (r = 0.988). In conclusion, in areas with high incidence of blooms, shellfish show a high activity of antioxidants, however, during the stages involving the distribution and bioconversion of toxins, there is decreased activity of antioxidant enzymes resulting in oxidative damage

Swimming versus running: effects on exhaled breath condensate pro-oxidants and pH

© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. Purpose: The respiratory redox-state of swimmers can be affected by chronic exposures to chlorinated pools, and the effects of different exercises on it are unknown. Our aim was to compare two exercises performed at high-intensity and under habitual environmental conditions (swimming indoor vs. running outdoor) on the production of pro-oxidants (hydrogen peroxide and nitrite) and pH in exhaled breath condensate (EBC) and spirometry parameters in competitive swimmers chronically exposed to chlorinated pools. Methods: Seventeen men and women (mean age ± SD = 21 ± 2 years) swam 3.5 km in an indoor pool treated with Cl2, and after 2-weeks, they ran 10 km outdoors. The pHEBC, [H2O2]EBC, [NO2 −]EBC, [NO2 −]EBC/[NO2 −]Plasma and spirometry parameters were analyzed pre-exercise and 20 min and 24 h after exercise ended. Results: Two mixed models were applied to compare EBC parameters between swimming and running. Lower levels of [H

Pulmonary Effects Due to Physical Exercise in Polluted Air: Evidence from Studies Conducted on Healthy Humans

Physical inactivity has caused serious effects on the health of the population, having an impact on the quality of life and the cost of healthcare for many countries. This has motivated government and private institutions to promote regular physical activity, which, paradoxically, can involve health risks when it is carried out in areas with poor air quality. This review collects information from studies conducted on healthy humans related to the pulmonary effects caused by the practice of physical activity when there is poor air quality. In addition, several challenges related to the technological and educational areas, as well as to applied and basic research, have been identified to facilitate the rational practice of exercise in poor air quality conditions