Monitoring Changes in Oxygen Muscle during Exercise with High-Flow Nasal Cannula Using Wearable NIRS Biosensors.

Exercise increases the cost of breathing (COB) due to increased lung ventilation (V˙E), inducing respiratory muscles deoxygenation (∇SmO2), while the increase in workload implies ∇SmO2 in locomotor muscles. This phenomenon has been proposed as a leading cause of exercise intolerance, especially in clinical contexts. The use of high-flow nasal cannula (HFNC) during exercise routines in rehabilitation programs has gained significant interest because it is proposed as a therapeutic intervention for reducing symptoms associated with exercise intolerance, such as fatigue and dyspnea, assuming that HFNC could reduce exercise-induced ∇SmO2. SmO2 can be detected using optical wearable devices provided by near-infrared spectroscopy (NIRS) technology, which measures the changes in the amount of oxygen bound to chromophores (e.g., hemoglobin, myoglobin, cytochrome oxidase) at the target tissue level. We tested in a study with a cross-over design whether the muscular desaturation of m.vastus lateralis and m.intercostales during a high-intensity constant-load exercise can be reduced when it was supported with HFNC in non-physically active adults. Eighteen participants (nine women; age: 22 ± 2 years, weight: 65.1 ± 11.2 kg, height: 173.0 ± 5.8 cm, BMI: 21.6 ± 2.8 kg·m-2) were evaluated in a cycle ergometer (15 min, 70% maximum watts achieved in ergospirometry (V˙O2-peak)) breathing spontaneously (control, CTRL) or with HFNC support (HFNC; 50 L·min-1, fiO2: 21%, 30 °C), separated by seven days in randomized order. Two-way ANOVA tests analyzed the ∇SmO2 (m.intercostales and m.vastus lateralis), and changes in V˙E and ∇SmO2·V˙E-1. Dyspnea, leg fatigue, and effort level (RPE) were compared between trials by the Wilcoxon matched-paired signed rank test. We found that the interaction of factors (trial × exercise-time) was significant in ∇SmO2-m.intercostales, V˙E, and (∇SmO2-m.intercostales)/V˙E (p < 0.05, all) but not in ∇SmO2-m.vastus lateralis. ∇SmO2-m.intercostales was more pronounced in CTRL during exercise since 5' (p < 0.05). Hyperventilation was higher in CTRL since 10' (p < 0.05). The ∇SmO2·V˙E-1 decreased during exercise, being lowest in CTRL since 5'. Lower dyspnea was reported in HFNC, with no differences in leg fatigue and RPE. We concluded that wearable optical biosensors documented the beneficial effect of HFNC in COB due to lower respiratory ∇SmO2 induced by exercise. We suggest incorporating NIRS devices in rehabilitation programs to monitor physiological changes that can support the clinical impact of the therapeutic intervention implemented.

Systemic and Pulmonary Inflammation/Oxidative Damage: Implications of General and Respiratory Muscle Training in Chronic Spinal-Cord-Injured Patients.

Chronic spinal cord injury affects several respiratory-function-related parameters, such as a decrease in respiratory volumes associated with weakness and a tendency to fibrosis of the perithoracic muscles, a predominance of vagal over sympathetic action inducing airway obstructions, and a difficulty in mobilizing secretions. Altogether, these changes result in both restrictive and obstructive patterns. Moreover, low pulmonary ventilation and reduced cardiovascular system functionality (low venous return and right stroke volume) will hinder adequate alveolar recruitment and low O2 diffusion, leading to a drop in peak physical performance. In addition to the functional effects described above, systemic and localized effects on this organ chronically increase oxidative damage and tissue inflammation. This narrative review describes both the deleterious effects of chronic spinal cord injury on the functional effects of the respiratory system as well as the role of oxidative damage/inflammation in this clinical context. In addition, the evidence for the effect of general and respiratory muscular training on the skeletal muscle as a possible preventive and treatment strategy for both functional effects and underlying tissue mechanisms is summarized.

An Igor Pro 8.01 Procedure to Analyze Pulse Oximetry during Acute Hypoxia Test in Aircrews.

The recognition of hypoxia symptoms is a critical part of physiological training in military aviation. Acute exposure protocols have been designed in hypobaric chambers to train aircrews to recognize hypoxia and quickly take corrective actions. The goal of the acute hypoxia test is to know the time of useful consciousness and the minimal arterial oxygen saturation tolerated. Currently, there is no computer system specifically designed to analyze the physiological variables obtained during the test. This paper reports the development and analytical capabilities of a computational tool specially designed for these purposes. The procedure was designed using the Igor Pro 8.01 language, which processes oxygen saturation and heart rate signals. To accomplish this, three functional boards are displayed. The first allows the loading and processing of the data. The second generates graphs that allow for a rapid visual examination to determine the validity of individual records and calculate slopes on selected segments of the recorded signal. Finally, the third can apply filters to generate data groups for analysis. In addition, this tool makes it possible to propose new study variables that are derived from the raw signals and can be applied simultaneously to large data sets. The program can generate graphs accompanied by basic statistical parameters and heat maps that facilitate data visualization. Moreover, there is a possibility of adding other signals during the test, such as the oxygenation level in vital organs, electrocardiogram, or electroencephalogram, which illustrates the test's excellent potential for application in aerospace medicine and for helping us develop a better understanding of complex physiological phenomena.

Update on the diagnosis, management and treatment of fever of unknown origin: review article and case report / Actualización en el diagnóstico, manejo y tratamiento de la fiebre de origen desconocido: artículo de revisión y reporte de caso

INTRODUCTION Actually, there are more than 200 different causes of unknown fever, it is necessary for the doctor to identify the most prevalent causes of unknown fever in our Clinical boar. PRESENTATION A 52-year-old male patient with no history of chronic diseases, which was received in the Emergency Service of the Hospital San Pablo, Coquimbo, on 02/03/20 began a clinical picture characterized by fever up to 39 ºC associated with diaphoresis, evaluated several times in primary health care without response to symptomatic treatment. He denies dyspnea, cough, sputum production, headache, muscle weakness, myalgia, fainting, decreased visual acuity, nausea, vomiting, chest pain, abdominal pain, diarrhea, constipation, altered bowel movements, weight loss, dysuria, bladder tenesmus, pain lumbar, skin lesions. As relevant information, the patient reports having taken amoxicillin/clavulanate for 2 days on his own account. DISCUSSION Physicians should be aware of the rare extent of an unusual presentation of knowledge origin fever, probably associated with Still disease, as well as medical options for treatment. The literature does not conclude on a gold standard for the method of approach. CONCLUSION In our case, the etiological agent that could cause Fever of unknown origin (FUO) was Sars cov-2 given the presence of elevated inflammatory factors and acute phase proteins and the presence of neutrophilic infiltration

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 "Handicap" versus "Conditional" 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 ("Handicap"; n = 214) versus a heterogeneous group ("Conditional"; n = 95) were compared using simple correlations (Spearman'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 "Handicap" group. Similar results were observed only in 1000 m for the "Conditional" 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 "Handicap" 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'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.

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 supplementation.

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 (eight males; 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, Student's t-test) between methods used (RCPvisual and RCPNIRS). We concluded that changes at SmO2-m.intercostales measured by NIRS could adequately determine RCP in triathletes.

H2O2 Concentration in Exhaled Breath Condensate Increases After Phonotrauma: A Promise of Noninvasive Monitoring?

PURPOSE: The present study was designed to observe the concentration of hydrogen peroxide (H2O2) in exhaled breath condensate (EBC) after induced phonotrauma. METHODS: Thirty-five participants were randomly assigned to one of two conditions (1) Vocal demand and (2) Control. Participants in the experimental group (vocal demand) were asked to read aloud some texts during 1 hour, at 85-90 dB. Inflammation (H2O2 from exhaled breath condensate), acoustic, aerodynamic, and subjective measures were obtained at four time points: before vocal demand (baseline), immediately after baseline, 4-hour after baseline, and 24 hours after baseline. The same acquisition process was implemented for subjects in control group, except that they were not asked to engage in any vocal demand tasks at all. RESULTS: As for biological samples, a significant effect for group was observed. Higher values were found for participants in experimental condition. Significant differences were observed for within contrasts in the experimental group, namely 4 hours against baseline, 4 hours against immediately post, and 24 hours against 4 hours. Instrumental outcomes did not show significant differences across the different conditions at any time points. Self-reported measures (vocal fatigue and sensation of muscle tension) showed a significant main effect for group and main effect for condition. CONCLUSIONS: Intense vocal demand causes an increase in the concentration of H2O2 obtained from EBC at four hours after baseline, which is compatible with the generation of an inflammatory process in the vocal folds (phonotrauma). Moreover, the increase in the sensation of vocal fatigue and muscle tension after demand tasks seems to be an immediate reaction that did not match in time with the increment of H2O2 concentration.

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 < 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 < 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.

Average and Interindividual Effects to a Comprehensive Cardiovascular Rehabilitation Program.

Background: To describe the average effects and the interindividual variability after a comprehensive outpatient cardiovascular rehabilitation (CCR) program using concurrent exercise training prescribed according to cardiovascular risk stratification on cardiorespiratory fitness (CRF), anthropometric/body composition, quality of life and emotional health in patients of four cardiovascular disease profiles. Methods: CRF, anthropometric/body composition, quality of life, and emotional health were measured before and after a CCR and analyzed in heart valve surgery (HVS), heart failure with reduced ejection fraction (HFrEF), post-acute myocardial infarction (post-AMI), and in coronary artery disease (CAD) patients. Twenty, twenty-four, and thirty-two exercise sessions were prescribed according to mild, moderate, and severe baseline cardiovascular risk, respectively. In addition to concurrent exercise training, nutritional counseling, psychological support, and lifestyle education programs were performed. Results: The main outcomes by delta changes comparisons (Δ) revealed no significant differences at anthropometric/body composition as ΔBody fat decreases (HVS Δ−1.1, HFrEF Δ−1.0, post-AMI Δ−1.4, CAD Δ−1.2 kg) and ΔSkeletal muscle mass increases (HVS Δ+1.4, HFrEF Δ+0.8, post-AMI Δ+0.9, CAD Δ+0.9 kg), and CRF performance as ΔVO2peak increases (HVS Δ+4.3, HFrEF Δ+4.8, post-AMI Δ+4.1, CAD Δ+5.1 mL/kg/min) outcomes among HVS, HFrEF, post-AMI, and CAD (p > 0.05). Secondary outcomes showed significant pre-post delta changes in METs (HVS Δ+1.8, HFrEF Δ+0.7, post-AMI Δ+1.4, CAD Δ+1.4), and maximal O2pulse (HVS Δ+3.1, post-AMI Δ+2.1, CAD Δ+1.9). In addition, quality of life had a significant improvement in physical functioning (HVS Δ+17.0, HFrEF Δ+12.1, post-AMI Δ+9.8, CAD Δ+11.2), physical role (HVS Δ+28.4, HFrEF Δ+26.8, post-AMI Δ+25.6, CAD Δ+25.3), vitality (HVS Δ+18.4, HFrEF Δ+14.3, post-AMI Δ+14.2, CAD Δ+10.6) and social functioning (HVS Δ+20.4, HFrEF Δ+25.3, post-AMI Δ+20.4, CAD Δ+14.8) in all cardiovascular disease. For anxiety (HVS Δ−3.6, HFrEF Δ−2.3, post-AMI Δ−3.0, CAD Δ−3.1) and depression (HVS Δ−2.8, HFrEF Δ−3.4, post-AMI Δ−3.2, CAD Δ−2.3) significant changes were also observed. Conclusions: A CCR program that prescribes the number of exercise sessions using a cardiovascular risk stratification improves CRF, QoL, and emotional health, and the average results show a wide interindividual variability (~25% of non-responders) in this sample of four CVD profile of patients.

Oxidative Stress Parameters and Morphological Changes in Japanese Medaka (Oryzias latipes) after Acute Exposure to OA-Group Toxins.

Toxins of the OA-group (okadaic acid, OA; dinophysistoxin-1, DTX-1) are the most prevalent in the fjords of southern Chile, and are characterized by their potential harmful effects on aquatic organisms. The present study was carried out to determine the acute toxicity of OA/DTX-1 on oxidative stress parameters in medaka (Oryzias latipes) larvae. Medaka larvae were exposed to different concentrations (1.0-30 µg/mL) of OA/DTX-1 for 96 h to determine the median lethal concentration. The LC50 value after 96 h was 23.5 µg/mL for OA and 16.3 µg/mL for DTX-1 (95% confidence interval, CI was 22.56, 24.43 for OA and 15.42, 17.17 for DTX-1). Subsequently, larvae at 121 hpf were exposed to acute doses (10, 15 and 20 µg/mL OA and 5.0, 7.5 and 11.0 µg/mL DTX-1) for 96 h and every 6 h the corresponding group of larvae was euthanized in order to measure the activity levels of biochemical biomarkers (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPx; and glutathione reductase, GR) as well as the levels of oxidative damage (malondialdehyde, MDA; and carbonyl content). Our results showed that acute doses caused a decrease in SOD (≈25%), CAT (≈55%), and GPx and GR (≈35%) activities, while MDA levels and carbonyl content increased significantly at the same OA/DTX-1 concentrations. This study shows that acute exposure to OA-group toxins tends to simultaneously alter the oxidative parameters that induce sustained morphological damage in medaka larvae. DTX-1 stands out as producing greater inhibition of the antioxidant system, leading to increased oxidative damage in medaka larvae. Considering that DTX-1 is the most prevalent HAB toxin in southern Chile, these findings raise the possibility of an important environmental impact on the larval stages of different fish species present in the southern fjords of the South Pacific.

Sex-Differences in the Oxygenation Levels of Intercostal 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.

Intercostal Muscles Oxygenation and Breathing Pattern during Exercise in Competitive Marathon Runners.

The study aimed to evaluate the association between the changes in ventilatory variables (tidal volume (Vt), respiratory rate (RR) and lung ventilation (V.E)) and deoxygenation of m.intescostales (∆SmO2-m.intercostales) during a maximal incremental exercise in 19 male high-level competitive marathon runners. The ventilatory variables and oxygen consumption (V.O2) were recorded breath-by-breath by exhaled gas analysis. A near-infrared spectroscopy device (MOXY®) located in the right-hemithorax allowed the recording of SmO2-m.intercostales. To explore changes in oxygen levels in muscles with high demand during exercise, a second MOXY® records SmO2-m.vastus laterallis. The triphasic model of exercise intensity was used for evaluating changes in SmO2 in both muscle groups. We found that ∆SmO2-m.intercostales correlated with V.O2-peak (r = 0.65; p = 0.002) and the increase of V.E (r = 0.78; p = 0.001), RR (r = 0.54; p = 0.001), but not Vt (p = 0.210). The interaction of factors (muscles × exercise-phases) in SmO2 expressed as an arbitrary unit (a.u) was significant (p = 0.005). At VT1 there was no difference (p = 0.177), but SmO2-m.intercostales was higher at VT2 (p < 0.001) and V.O2-peak (p < 0.001). In high-level competitive marathon runners, the m.intercostales deoxygenation during incremental exercise is directly associated with the aerobic capacity and increased lung ventilation and respiratory rate, but not tidal volume. Moreover, it shows less deoxygenation than m.vastus laterallis at intensities above the aerobic ventilatory threshold.

Changes in pulmonary and plasma oxidative stress and inflammation following eccentric and concentric cycling in stable COPD patients.

PURPOSE: The purpose of this study was to compare pulmonary and plasma markers of oxidative stress and inflammation after concentric and eccentric cycling bouts in individuals with chronic obstructive pulmonary disease (COPD). METHODS: Ten patients with moderate COPD level (68.3 ± 9.1 years; forced expiratory volume in 1 s = 68.6 ± 20.4% of predicted) performed 30 min of moderate-intensity concentric (CONC-M: 50% maximum concentric cycling power output; POmax) and eccentric cycling (ECC-M: 50% POmax), and high-intensity eccentric cycling (ECC-H: 100% POmax) in a randomised order. Cardiometabolic demand was monitored during cycling. Indirect markers of muscle damage were assessed before, immediately after, 24 and 48 h after cycling (muscle strength, muscle soreness and creatine kinase activity). Plasma oxidative stress (malondialdehyde: MDA), antioxidant (glutathione peroxidase activity: GPx) and inflammatory markers (IL-6, TNF-α) were measured before and 5 min after cycling. Exhaled breath condensate (EBC) samples were collected before and 15 min after cycling and analysed for hydrogen peroxide (H2O2), nitrites (NO2-) and pH. RESULTS: Cardiometabolic demand was 40-50% lesser for ECC-M than CONC-M and ECC-H. Greater muscle damage was induced after ECC-H than ECC-M and CONC-M. MDA decreased immediately after CONC-M (- 28%), ECC-M (- 14%), and ECC-H (- 17%), while GPx remained unchanged. IL-6 increased only after ECC-H (28%), while TNF-α remained unchanged after exercise. Pulmonary H2O2, NO2- and pH remained unchanged after exercise. CONCLUSION: These results suggest that only moderate muscle damage and inflammation were induced after high-intensity eccentric cycling, which did not induce pulmonary or plasmatic increases in markers of oxidative stress. TRIAL REGISTRATION NUMBER: Trial registration number: DRKS00009755.

Humidity prevents the exercise-induced formation of hydrogen peroxide and nitrite in exhaled breath condensate in recreational cyclists.

PURPOSE: The aerobic exercise affects the respiratory redox-state. The influence of different relative humidity (RH) levels on the formation of respiratory reactive chemical species associated with redox-state altered by exercise has been poorly explored. Our aim was to evaluate the effect of two different RH conditions (40% vs. 90%) on the concentration of hydrogen peroxide and nitrite in exhaled breath condensate ([H2O2]EBC and [NO2-]EBC) and spirometry parameters in recreational cyclists. METHODS: Sixteen men and women (12/4) (mean age ± SD: 23.5 ± 2.2 years) completed 60-min of cycling at 166.3 ± 26.9 watts (70% of maximum load of [Formula: see text]-max. test, 49.3 ± 7.6 mL·min-1·kg-1) at random 40%-RH and 90%-RH conditions separated by 7 days. The two-way RM-ANOVA test was applied to compare [H2O2]EBC, [NO2-]EBC, [NO2-]EBC/[NO2-]Plasma at rest and 80-min post-exercise (80-post); and spirometry parameters at rest, 20-post and 80-post. RESULTS: The interaction of factors (humidity × time) was significant in [H2O2]EBC, [NO2-]EBC, [NO2-]EBC/[NO2-]Plasma (p = 0.005, p = 0.030, p = 0.043, respectively). At 40%-RH conditions, the same parameters were higher in 80-post than at rest (p < 0.001, p = 0.001, p = 0.014, respectively). At the same time, the [H2O2]EBC and [NO2-]EBC/[NO2-]Plasma were higher in 40%-RH than 90%-RH (p = 0.010, p < 0.001, respectively). The interaction was significant in FEV1 (p = 0.013) and FEF25-75% (p = 0.023), but not in FEV1/FVC (p = 0.362). At 80-post, the changes are kept in 90%-RH (p < 0.001), diminishing in 40%-RH being similar to rest. CONCLUSION: In recreational cyclists, 90%-RH prevents the increase of hydrogen peroxide and nitrite in exhaled breath condensate samples observed at 40%-RH and prolonging the bronchodilation until 80-post cycling exercise.

Centro de presión y patrones de actividad muscular durante la ejecución de una sentadilla monopodal isométrica realizada sobre una superficie esponjosa en mujeres jóvenes sanas / Center of pressure and patterns of muscular activity during the execution of an isometric single leg squat performed on a spongy surface in healthy young women / Centro de pressão e padrões de atividade muscular durante a execução de um agachamento isométrico uni podal realizado em uma superfície esponjosa por mulheres jovens saudáveis

Objetivo: Comparar la ejecución del ejercicio de sentadilla monopodal isométrica, en una superficie rígida versus una superficie esponjosa, en relación al centro de presión y los patrones de activación de la musculatura de la extremidad inferior dominante y la columna, en mujeres jóvenes sanas. Método: 12 mujeres sanas, realizaron la sentadilla monopodal isométrica en una superficie rígida (control) y una superficie esponjosa. Un posturógrafo registró el área y velocidad de desplazamiento del centro de presión. Un electromiógrafo de superficie evaluó la actividad muscular de multífido, glúteo mayor, glúteo medio, vasto medial y bíceps femoral de la pierna de apoyo. Resultados: El área y la velocidad de desplazamiento del centro de presión aumentó (p<0.05 y p<0.01 respectivamente) en superficie esponjosa. El bíceps femoral aumenta su actividad muscular en superficie esponjosa (p<0.05). Existe correlación entre la mayor actividad muscular del bíceps femoral y el área y la velocidad del centro de presión (p<0.01). Conclusión: La sentadilla monopodal isométrica realizada sobre una superficie esponjosa, produce una mayor perturbación del control postural y una mayor actividad del bíceps femoral en mujeres jóvenes sanas. El aumento de actividad de este músculo se relaciona directamente con el desplazamiento del centro de presión

Objective: To compare the performance of the isometric single leg squat exercise on a rigid surface versus a spongy surface in relation to the center of pressure and activation patterns of the muscles of the dominant lower limb and spine in healthy young women. Method: 12 healthy women performed the isometric single leg squat on a rigid surface (control) and a spongy surface. A posturograph recorded the area and velocity of displacement of the pressure center. A surface electromyograph evaluated the muscular activity of multifidus, gluteus maximus, gluteus medius, vastus medialis and biceps femoris of the supporting leg. Results: The area and the speed of displacement of the center of pressure increased (p <0.05 and p <0.01 respectively) in spongy surface. Femoral biceps increase its muscular activity on the spongy surface (p <0.05). There is a correlation between the greater muscular activity of the biceps femoris and the area and the velocity of the pressure center (p <0.01). Conclusion: Isometric single leg squat performed on a spongy surface, produces a greater disturbance of postural control and greater activity of the biceps femoris in healthy young women. The increased activity of this muscle is directly related to the displacement of the pressure center

Objetivo: Comparar o desempenho no agachamento isométrico uni podal em superfície rígida versus superfície esponjosa em relação ao centro de pressão e padrões de ativação dos músculos do membro inferior dominante e coluna vertebral em mulheres jovens saudáveis. Método: 12 mulheres saudáveis realizaram o agachamento isométrico uni podal em uma superfície rígida (controle) e uma superfície esponjosa. Um posturógrafo registrou a área e a velocidade de deslocamento do centro de pressão. Um eletromiógrafo de superfície avaliou a atividade muscular de multifidus, glúteo máximo, glúteo médio, vasto medial e bíceps femoral da perna de apoio. Resultados: A área e a velocidade de deslocamento do centro de pressão aumentaram (p <0.05 e p <0.01, respectivamente) na superfície esponjosa. O bíceps femoral aumenta sua atividade muscular na superfície esponjosa (p <0.05). Existe uma correlação entre a maior atividade muscular do bíceps femoral e a área e a velocidade do centro de pressão (p <0.01). Conclusão: Agachamento isométrico uni podal realizado em uma superfície esponjosa, produz uma maior perturbação do controle postural e uma maior atividade do bíceps femoral em mulheres jovens saudáveis. O aumento da atividade desse músculo está diretamente relacionado ao deslocamento do centro de pressão

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

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 [H2O2]EBC and [NO2-]EBC (p = 0.008 and p = 0.018, respectively) were found 24-h post-swimming, and the same trend was observed for [NO2-]EBC/[NO2-]Plasma (p = 0.062). Correlations were found in both exercises between pre-exercise levels of pHEBC, [H2O2]EBC, [NO2-]EBC, and [NO2-]EBC/[NO2-]Plasma and their changes (Δ) after 24-h as well as between [H2O2]EBC and [NO2-]EBC for basal levels and for changes after 24 h. A relationship was also found for running exercise between pulmonary ventilation and changes after 24 h in [H2O2]EBC. Spirometry data were unaffected in both types of exercise. CONCLUSION: In competitive swimmers, at 24-h acute post-exercise follow-up, swimming decreased and running increased pro-oxidant biomarkers of pulmonary origin, without changes in lung function.

Melatonin Relations With Respiratory Quotient Weaken on Acute Exposure to High Altitude.

High altitude (HA) exposure may affect human health and performance by involving the body timing system. Daily variations of melatonin may disrupt by HA exposure, thereby possibly affecting its relations with a metabolic parameter like the respiratory quotient (RQ). Sea level (SL) volunteers (7 women and 7 men, 21.0 ± 2.04 y) were examined for daily changes in salivary melatonin concentration (SMC). Sampling was successively done at SL (Antofagasta, Chile) and, on acute HA exposure, at nearby Caspana (3,270 m asl). Saliva was collected in special vials (Salimetrics Oral Swab, United Kingdom) at sunny noon (SMCD) and in the absence of blue light at midnight (SMCN). The samples were obtained after rinsing the mouth with tap water and were analyzed for SMC by immunoassay (ELISA kit; IBL International, Germany). RQ measurements (n = 12) were realized with a portable breath to breath metabolic system (OxiconTM Mobile, Germany), between 8:00 PM and 10:00 PM, once at either location. At SL, SMCD, and SMCN values (mean ± SD) were, respectively, 2.14 ± 1.30 and 11.6 ± 13.9 pg/ml (p < 0.05). Corresponding values at HA were 8.83 ± 12.6 and 13.7 ± 16.7 pg/ml (n.s.). RQ was 0.78 ± 0.07 and 0.89 ± 0.08, respectively, at SL and HA (p < 0.05). Differences between SMCN and SMCD (SMCN-SMCD) strongly correlate with the corresponding RQ values at SL (r = -0.74) and less tight at HA (r = -0.37). Similarly, mean daily SMC values (SMC) tightly correlate with RQ at SL (r = -0.79) and weaker at HA (r = -0.31). SMCN-SMCD, as well as, SMC values at SL, on the other hand, respectively, correlate with the corresponding values at HA (r = 0.71 and r = 0.85). Acute exposure to HA appears to loosen relations of SMC with RQ. A personal profile in daily SMC variation, on the other hand, tends to be conserved at HA.

Efectos de la exposición aguda a gran altitud en jugadores profesionales de fútbol aclimatados y no aclimatados / Effects of acute exposure to high altitude in acclimatized and non-acclimatized professional soccer player

Objetivo: Evaluar la respuesta cardiopulmonar, equilibrio ácido base y gases en una prueba cardiopulmonar máxima en futbolistas profesionales de primera división de Bolivia residentes de altitudes bajas, medidos durante las primeras seis horas de llegada a la gran altura de 3.600 m. Métodos: A once futbolistas bolivianos residentes a 150 m (lowlanders, LL) y diez residentes a 3.600 m (highlanders, HL) se les realizó el Yo-Yo endurance test con ergoespirometría, determinación de pH, exceso de bases (EB), gases y lactato en sangre capilar a 150 m y a 3.600 m una semana después. Resultados: El VO2 max (L*min-1) disminuyó a 3.600 m en ambos grupos estudiados, sin diferencia entre el lugar de residencia y altitud. En LL (p<0.001) 3,52±0,46 vs 2,92±0,38. En HL (p<0.001) 4,02±0,5 vs 3,41±0,45. La distancia máxima recorrida (metros) fue menor en altura (3.600 m) en ambos grupos, 1.903,64±202,55 vs 1.358,2±210,6 (p<0.001) en LL, y 2.096,0±272,4 vs 1.605,0±281,17 (p<0.001) en HL. Pre-ejercicio a 3.600 m, los LL tuvieron mayor pCO2 (38,3±3,0 vs 30,69±1,78 mmHg; p<0.001 y menor satO2 (83,1± 2,7 vs 88,1 ± 1,1%; p<0.01). El ejercicio en altura generó en LL mayores decrementos de pH (-0,258±0,06 vs -0,206±0,03; p<0.05) y de EB (-18,73±2,83 vs -12,62±2,13) sin diferencias en lactato sérico (10,8 ± 2,09 vs 9,43 ± 2,1 mmol/L para LL y HL respectivamente). Conclusión: En las primeras seis horas a 3.600 m, la caída del rendimiento aeróbico es similar en LL y HL, a pesar de una menor respuesta ventilatoria y oxigenación en reposo del grupo LL, además en ejercicio se genera una mayor acidosis metabólica en LL en ambas alturas

Objective: To evaluate the cardiopulmonary response, gases and acid base balance in a cardiorespiratory maximal test applied to professional football players of first division of Bolivia living at low altitude, during the first six hours after arrival to the high altitude of 3,600 meters. Methods: Eleven Bolivian players living at an altitude of 150 m (lowlanders, LL) and ten highlanders (HL), living at an altitude of 3,600 m, performed the Yo-Yo endurance test with ergospirometry. Base excess (BE), pH, blood gases and capillary blood lactate were determined at 150 m and at 3,600 m seven days later. Results: VO2 max (L·min-1) decreased at 3,600 m in both groups, without differences in slopes or interaction between the factors residence and altitude. In LL (p<.001), 3.52±0.46 vs 2.92±0.38. In HL (p<.001) 4.02±0.5 vs 3.41±0.45. The distance covered in the test was lower at 3,600 m in both groups: 1358.2±210.6 vs 1903.64±202.55 m in LL (p < .001) and 1605.0±281.17 vs 2096.0±272.4 m in HL (p < .001). Pre-exercise at 3600 m, LL had a higher pCO2 (38.3 ± 3.0 vs 30.69 ± 1.78 mmHg; p<.001) and a lower satO2 (83.1± 2.7 vs 88.1 ± 1.1% p<.01) Exercise performed at high altitude produced in LL a higher decrement in pH (-0.258 ± 0.06 vs -0.206 ± 0.03; p<.05) and in BE (-18.73±2.83 vs -12.62±2.13) with no differences in blood lactate (10.8 ± 2.09 vs 9.43 ± 2.1 mmol/L for LL and HL, respectively). Conclusion: During the first six hours at 3,600 m, aerobic performance decrease is similar in LL and HL, although a lower ventilatory response and resting oxygenation of the LL group is found. LL group also showed a greater metabolic acidosis in both altitudes during exercise