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.

Reliability of NIRS portable device for measuring intercostal muscles oxygenation during exercise.

This study assessed the intra-individual reliability of oxygen saturation in intercostal muscles (SmO2-m.intercostales) during an incremental maximal treadmill exercise by using portable NIRS devices in a test-retest study. Fifteen marathon runners (age, 24.9 ± 2.0 years; body mass index, 21.6 ± 2.3 kg·m-2; V̇O2-peak, 63.7 ± 5.9 mL·kg-1·min-1) were tested on two separate days, with a 7-day interval between the two measurements. Oxygen consumption (V̇O2) was assessed using the breath-by-breath method during the V̇O2-test, while SmO2 was determined using a portable commercial device, based in the near-infrared spectroscopy (NIRS) principle. The minute ventilation (VE), respiratory rate (RR), and tidal volume (Vt) were also monitored during the cardiopulmonary exercise test. For the SmO2-m.intercostales, the intraclass correlation coefficient (ICC) at rest, first (VT1) and second ventilatory (VT2) thresholds, and maximal stages were 0.90, 0.84, 0.92, and 0.93, respectively; the confidence intervals ranged from -10.8% - +9.5% to -15.3% - +12.5%. The reliability was good at low intensity (rest and VT1) and excellent at high intensity (VT2 and max). The Spearman correlation test revealed (p ≤ 0.001) an inverse association of SmO2-m.intercostales with V̇O2 (ρ = -0.64), VE (ρ = -0.73), RR (ρ = -0.70), and Vt (ρ = -0.63). The relationship with the ventilatory variables showed that increased breathing effort during exercise could be registered adequately using a NIRS portable device.

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.

Increased active phase atrial contraction is related to marathon runner performance.

PURPOSE: Left atrial (LA) contraction is essential for left ventricular (LV) filling during exertion. We sought to evaluate the relationship of LA contraction and exercise capacity in trained athletes. METHODS: Sixteen male marathon runners were recruited and allocated into two groups according to their previous training status (≥ or < 100 km peer week). All subjects underwent a baseline cardiopulmonary test to evaluate maximal aerobic capacity and a transthoracic echocardiography previous and immediate post-marathon. LA contractile function evaluation was accomplished by measuring the negative deformation of the post P wave strain curve (LASa). LASa change was defined as LASa pre-marathon minus LASa immediate post-marathon. RESULTS: Mean age was 39 ± 6 years. LA volume index (39 ± 13 vs. 31 ± 5 mL/m2, p = 0.04), LV mass index (91 ± 21 vs. 73 ± 12 g/m2, p = 0.04), VO2 max (59 ± 3 vs. 50 ± 8 mL/kg/min, p = 0.036) were higher in more intensive trained group and marathon time was lower (185 ± 14 vs. 219 ± 24 min, p = 0.017). An increase in LASa after immediate post-marathon was observed in both groups, which was significantly greater in the highly trained group (18.9 ± 5.8 vs. 6.3 ± 3.5%, p < 0.003). Maximum VO2 measured previous to the marathon was inversely related to marathon time and directly correlated to LASa change (rho = 0.744, p = 0.001, rho = 0.546, p = 0.028, respectively). CONCLUSIONS: Athletes with more intensive training load have larger LV mass and LA size. An increase in LA contraction was seen post-marathon, which was significantly greater in the highly trained group. This increase in the LA contraction was related to the maximum VO2 measured previous to the marathon and to performance in a highly demanding test.

Sonographic Measurement of the Quadriceps Muscle in Patients With Chronic Obstructive Pulmonary Disease: Functional and Clinical Implications.

OBJECTIVES: The purpose of this study was to determine the association between functionality as assessed by the 6-minute walking test (6MWT), maximal voluntary contraction of the quadriceps (MVCQ), and quadriceps thickness and echo intensity as measured by sonography, in patients with chronic obstructive pulmonary disease (COPD). METHODS: Maximal voluntary contraction of the quadriceps and the thickness and echo intensity of the rectus femoris and vastus intermedius were evaluated in 20 patients with COPD. Functionality was assessed by the 6MWT. Differences between the evaluated muscles were determined by the Student t test. Pearson and Spearman rank correlation coefficients were used to analyze relationships between variables of interest, according to data characteristics. Finally, multivariate regression models were applied. RESULTS: There was a positive correlation between MVCQ and rectus femoris and vastus intermedius thickness (r = 0.427; P = .030; r = 0.469; P= .018, respectively) and a negative correlation between MVCQ and rectus femoris and vastus intermedius echo intensity (r= -0.500; P= .012; r= -0.482; P= .016). No correlation was found between MVCQ and the 6MWT (r = 0.319; P = .085). Multivariate regression analysis showed that the rectus femoris echo intensity, vastus intermedius echo intensity, and vastus intermedius thickness explained 70% of the variance in the distance walked during the 6MWT. CONCLUSIONS: These results indicate that, in patients with COPD, both quadriceps force and exercise capacity are associated with quantitative (thickness) and qualitative (echo intensity) characteristics of the quadriceps. Consequently, comprehensive assessments of peripheral muscles should simultaneously include both measurements.

Effectiveness of Respiratory Muscles Training by Voluntary Isocapnic Hyperpnea Versus Inspiratory Threshold Loading on Intercostales and Vastus Lateralis Muscles Deoxygenation Induced by Exercise in Physically Active Adults.

Respiratory muscle training (RMT) improves physical performance, although it is still debated whether this effect depends on the type of training. The purpose of this study was to compare the effects of two different types of RMT, i.e., voluntary isocapnic hyperpnea (VIH) and inspiratory threshold loading (ITL), on the deoxygenation of intercostal (ΔSmO2-m. intercostales) and vastus lateralis (ΔSmO2-m. vastus lateralis) muscles during exercise. Twenty-four participants performed eight weeks of RMT by: (i) VIH (3 days·week-1 for 12 min at 60% maximal voluntary ventilation) or (ii) ITL (5 sets·week-1 of 30 breaths·minute-1 at 60% maximal inspiratory pressure). Cardiopulmonary exercise testing (CPET) included ΔSmO2 (the change from baseline to end of test) of intercostal and vastus lateralis muscles. After RMT, both groups showed decreased ΔSmO2-m. intercostales (VIH = 12.8 ± 14.6%, p = 0.04 (effect size, ES = 0.59), and ITL = 8.4 ± 9.8%, p = 0.04 (ES = 0.48)), without a coincident change of ∆SmO2-m. vastus lateralis. ITL training induced higher V˙O2-peak absolute values than VIH (mean Δ post-pre, ITL = 229 ± 254 mL·min-1 [95% CI 67-391] vs. VIH, 39 ± 153 mL·min-1 [95% CI -58-136.0], p = 0.01). In conclusion, both RMT improved the balance between supply and oxygen consumption levels of m. intercostales during CPET, with ITL also inducing an increase of aerobic capacity.

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.

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.

Eccentric Training in Pulmonary Rehabilitation of Post-COVID-19 Patients: An Alternative for Improving the Functional Capacity, Inflammation, and Oxidative Stress.

The purpose of this narrative review is to highlight the oxidative stress induced in COVID-19 patients (SARS-CoV-2 infection), describe longstanding functional impairments, and provide the pathophysiologic rationale that supports aerobic eccentric (ECC) exercise as a novel alternative to conventional concentric (CONC) exercise for post-COVID-19 patients. Patients who recovered from moderate-to-severe COVID-19 respiratory distress demonstrate long-term functional impairment. During the acute phase, SARS-CoV-2 induces the generation of reactive oxygen species that can be amplified to a "cytokine storm". The resultant inflammatory and oxidative stress process causes organ damage, particularly in the respiratory system, with the lungs as the tissues most susceptible to injury. The acute illness often requires a long-term hospital stay and consequent sarcopenia. Upon discharge, muscle weakness compounded by limited lung and cardiac function is often accompanied by dyspnea, myalgia, anxiety, depression, and sleep disturbance. Consequently, these patients could benefit from pulmonary rehabilitation (PR), with exercise as a critical intervention (including sessions of strength and endurance or aerobic exercises). Unfortunately, conventional CONC exercises induce significant cardiopulmonary stress and increase inflammatory and oxidative stress (OS) when performed at moderate/high intensity, which can exacerbate debilitating dyspnoea and muscle fatigue post-COVID-19. Eccentric training (ECC) is a well-tolerated alternative that improves muscle mass while mitigating cardiopulmonary stress in patients with COPD and other chronic diseases. Similar benefits could be realized in post-COVID-19 patients. Consequently, these patients could benefit from PR with exercise as a critical intervention.

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.

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.

Left Cardiac Remodelling Assessed by Echocardiography Is Associated with Rho-Kinase Activation in Long-Distance Runners.

This single-blind and cross-sectional study evaluated the role of Rho-kinase (ROCK) as a biomarker of the cardiovascular remodelling process assessed by echocardiography in competitive long-distance runners (LDRs) during the training period before a marathon race. Thirty-six healthy male LDRs (37.0 ± 5.3 years; 174.0 ± 7.0 height; BMI: 23.8 ± 2.8; V˙ O2-peak: 56.5 ± 7.3 mL·kg-1·min-1) were separated into two groups according to previous training level: high-training (HT, n = 16) ≥ 100 km·week-1 and low-training (LT, n = 20) ≥ 70 and < 100 km·week-1. Also, twenty-one healthy nonactive subjects were included as a control group (CTR). A transthoracic echocardiography was performed and ROCK activity levels in circulating leukocytes were measured at rest (48 h without exercising) the week before the race. The HT group showed a higher left ventricular mass index (LVMi) and left atrial volume index (LAVi) than other groups (p < 0.05, for both); also, higher levels of ROCK activity were found in LDRs (HT = 6.17 ± 1.41 vs. CTR = 1.64 ± 0.66 (p < 0.01); vs. LT = 2.74 ± 0.84; (p < 0.05)). In LDRs a direct correlation between ROCK activity levels and LVMi (r = 0.83; p < 0.001), and LAVi (r = 0.70; p < 0.001) were found. In conclusion, in male competitive long-distance runners, the load of exercise implicated in marathon training is associated with ROCK activity levels and the left cardiac remodelling process assessed by echocardiography.

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.

Circulating Vascular Cell Adhesion Molecule-1 (sVCAM-1) Is Associated With Left Atrial Remodeling in Long-Distance Runners.

Introduction: An increased risk of atrial fibrillation (AF) has been demonstrated in high-performance athletes. Soluble vascular adhesion molecule-1 (sVCAM-1), a biomarker involved in inflammation and cardiac remodeling, is associated with the development of AF in the general population. However, the relationship between sVCAM-1 and left atrial (LA) remodeling has been poorly investigated in long-distance runners (LDR). Aim: To determine the association between LA remodeling and sVCAM-1 levels in LDR during the training period before a marathon race. Methods: Thirty-six healthy male LDR (37.0 ± 5.3 years; 174.0 ± 7.0 height; BMI: 23.8 ± 2.8; V°O2-peak: 56.5 ± 7.3 mL·kg-1·min-1) were evaluated in this single-blind and cross-sectional study. The LDR were separated into two groups according to previous training levels: high-training (HT) (n = 18) ≥100 km·week-1 and low-training (LT) (n = 18) ≥70 and <100 km·week-1. Also, 18 healthy non-active subjects were included as a control group (CTR). In all participants, transthoracic echocardiography was performed. sVCAM-1 blood levels were measured baseline and immediately finished the marathon race in LDR. Results: HT showed increased basal levels of sVCAM-1 (651 ± 350 vs. 440 ± 98 ng·mL-1 CTR, p = 0.002; and vs. 533 ± 133 ng·mL-1 LT; p = 0.003) and a post-marathon increase (ΔsVCAM-1) (651 ± 350 to 905 ± 373 ng·mL-1; p = 0.002), that did not occur in LT (533 ± 133 to 651 ± 138 ng·mL-1; p = 0.117). In LDR was a moderate correlation between LA volume and sVCAM-1 level (rho = 0.510; p = 0.001). Conclusions: In male long-distance runners, sVCAM-1 levels are directly associated with LA remodeling. Also, the training level is associated with basal sVCAM-1 levels and changes after an intense and prolonged exercise (42.2 km). Whether sVCAM-1 levels predict the risk of AF in runners remains to be established.

Soluble Interleukin-6 Receptor Regulates Interleukin-6-Dependent Vascular Remodeling in Long-Distance Runners.

Little is known about the effects of training load on exercise-induced plasma increase of interleukin-6 (IL-6) and soluble IL-6 receptor (sIL-6R) and their relationship with vascular remodeling. We sought to evaluate the role of sIL 6R as a regulator of IL-6-induced vascular remodeling. Forty-four male marathon runners were recruited and allocated into two groups: low-training (LT, <100 km/week) and high-training (HT, ≥100 km/week), 22 athletes per group. Twenty-one sedentary participants were used as reference. IL-6, sIL-6R and sgp130 levels were measured in plasma samples obtained before and immediately after finishing a marathon (42.2-km). Aortic diameter was measured by echocardiography. The inhibitory effect of sIL-6R on IL-6-induced VSMC migration was assessed using cultured A7r5 VSMCs. Basal plasma IL-6 and sIL-6R levels were similar among sedentary and athlete groups. Plasma IL-6 and sIL-6R levels were elevated after the marathon, and HT athletes had higher post-race plasma sIL-6R, but not IL-6, level than LT athletes. No changes in sgp130 plasma levels were found in LT and HT groups before and after running the marathon. Athletes had a more dilated ascending aorta and aortic root than sedentary participants with no differences between HT and LT athletes. However, a positive correlation between ascending aorta diameter and plasma IL-6 levels corrected by training load and years of training was observed. IL-6 could be responsible for aorta dilation because IL-6 stimulated VSMC migration in vitro, an effect that is inhibited by sIL-6R. However, IL-6 did not modify cell proliferation, collagen type I and contractile protein of VSMC. Our results suggest that exercise induces vascular remodeling. A possible association with IL-6 is proposed. Because sIL-6R inhibits IL-6-induced VSMC migration, a possible mechanism to regulate IL-6-dependent VSMC migration is also proposed.

Nonalcoholic fatty liver disease and sarcopenia: pathophysiological connections and therapeutic implications.

INTRODUCTION: Nonalcoholic fatty liver disease (NAFLD) is currently one of the most common liver diseases worldwide. Recent data suggest that loss of skeletal muscle mass and function (i.e. sarcopenia) is highly prevalent and frequently overlooked in NAFLD patients. Experimental and clinical data suggest that the relationship between NAFLD and sarcopenia is pathophysiologically complex and bi-directional and there is a growing interest in unveiling how sarcopenia could influence NAFLD development and progression. AREAS COVERED: PubMed/MEDLINE was searched for articles related to concomitant occurrence of NAFLD and sarcopenia between January 2013 and April 2020. Areas covered in this review include: (1) updated sarcopenia diagnosis strategy, (2) discussion of current data on pathophysiological connections between NAFLD and sarcopenia, and (3) analysis of current and future therapeutic implications of this knowledge. EXPERT OPINION: Clinical studies describe a consistent association between NAFLD and sarcopenia, although a cause-effect relation remains to be determined. Active implementation of current diagnosis algorithms and optimized treatment can prevent sarcopenia related complications in subjects with NAFLD. Pathogenic pathways implicated in this relation are multiple and complex, a better understanding of them can provide novel biomarkers and targeted therapies that will hopefully have an important impact in NAFLD management.

[Cardiometabolic risk and variation of fat/adipose content according to body mass index in children from six to nine years old]. / Riesgo cardiometabólico y variación en el contenido graso/adiposo según el índice de masa corporal en niños de seis a nueve años.

INTRODUCTION: Introduction: child excess weight has been associated with obesity in adulthood and, as a consequence, increased risk of death due to cardiometabolic factors. Objective: to identify whether BMI reflects changes in the content and distribution of fat/adipose tissue and the cardiometabolic risk in children between six and nine years old. Material and methods: participants were 537 children (59.8% women) randomly selected. BMI, waist circumference (WC), waist-height index (WHI), body composition, nutritional status and cardiometabolic risk were determined. Student's t-test, one-way ANOVA, Pearson's correlation, Chi-square and diagnostic concordance were applied. An alpha ≤ 0.05 was considered. Results: direct and significant correlations between nutritional status and the anthropometric parameters studied are shown, except for the percentage of adiposity. There were significant variations (p < 0.05) in the percentage of fat and adiposity according to nutritional status of the sample. In addition, there was consistency between the variation of the nutritional status with the cardiometabolic risk evaluated trough WC and WHI. Conclusion: BMI identifies the differences in the amount of fat/adipose tissue in the children between six and nine years old when categorized according to nutritional status. In addition, it reflects direct association with cardiometabolic risk.

INTRODUCCIÓN: Introducción: el exceso de peso infantil se ha asociado con obesidad en la etapa adulta y, por consecuencia, mayor riesgo de muerte por factores cardiometabólicos. Objetivo: identificar si el índice de masa corporal (IMC) refleja cambios en el contenido y la distribución del tejido graso/adiposo y el riesgo cardiometabólico en niños y niñas de seis a nueve años. Material y métodos: participaron 537 niños (59,8% mujeres) seleccionados aleatoriamente. Las variables estudiadas correspondieron al IMC, perímetro de cintura (PC), índice cintura-estatura (ICE), composición corporal, estado nutricional y riesgo cardiometabólico. Se utilizó la prueba de correlación de Pearson y Chi-cuadrado para la relación de las variables junto con la aplicación de un test de proporciones. Se aplicaron las pruebas t de Student para muestras no pareadas, ANOVA una vía y concordancia diagnóstica en la comparación entre grupos. Se consideró un alfa ≤ 0,05 para todos los casos. Resultados: se exhiben correlaciones directas y significativas entre el estado nutricional con los parámetros antropométricos estudiados, excepto el porcentaje de adiposidad. Se aprecian variaciones significativas (p < 0,05) en el porcentaje de grasa y adiposidad según estado nutricional de la muestra. Además, existe consistencia entre la variación del estado nutricional con el riesgo cardiometabólico evaluado a través del PC e ICE. Conclusión: el IMC identifica las diferencias en la cantidad de tejido graso/adiposo en niños y niñas situados entre los seis y los nueve años al ser categorizados según estado nutricional. Además, refleja asociación directa con el riesgo cardiometabólico.

Factor de crecimiento análogo a insulina-1 y cardiotrofina-1 inducido por ejercicio y su relación con hipertrofia miocárdica en maratonistas / Cardiotrophin-1 and Insulin like growth factor induced by exercise are associated to cardiac hypertrophy in marathon runners

Antecedentes: El ejercicio de alta intensidad induce hipertrofia miocárdica necesaria para adaptar al corazón a la mayor demanda de trabajo. Se desconoce si correr una maratón induce de forma aguda factores humorales asociados al desarrollo de hipertrofia miocárdica en atletas. Objetivo: Evaluar cardiotrofina-1 (CT1) y el factor de crecimiento análogo a insulina-1 (IGF-1), conocidos inductores de hipertrofia, en maratonistas previo y justo después de correr una maratón y su relación con hipertrofia cardíaca. Métodos: Estudio prospectivo ciego simple de atletas hombres que corrieron la maratón de Santiago. Se incluyó un grupo control sedentario. En todos los sujetos se realizó un ecocardiograma transtorácico estándar. Los niveles de CT1 e IGF-1 se determinaron en plasma obtenidos antes (basal) y justo después de haber terminado (antes de 15 minutos) la maratón, usando test de ELISA. Resultados: Los atletas tenían frecuencias cardíacas menores que los controles, asociado con una mayor hipertrofia miocárdica, determinado por el grosor del septo y pared posterior del corazón, y volúmenes del ventrículo y aurícula izquierda. Los niveles basales de CT1 e IGF-1 fueron similares entre atletas y controles sedentarios. El correr la maratón aumentó los niveles de estas dos hormonas en un subgrupo de atletas. Solo los atletas que incrementaron los niveles de IGF-1, pero no de CT1, tenían volúmenes de ventrículo izquierdo y derecho más grandes que los otros atletas. Conclusiones: IGF-1 que se incrementa de forma aguda por el ejercicio, pero no CT1, estaría asociado con el aumento de los volúmenes ventriculares observado en los atletas.

Background: High intensity exercise induces the development of myocardial hypertrophy necessary to adapt the heart to the increased work demand. Whether running a marathon is associated with acutely induced humoral factors responsible for the development of myocardial hypertrophy observed in athletes is not known. Objective: To evaluate the levels of cardiotrophin-1 (CT1) and insulin-like growth factor-1 (IGF-1), known hypertrophy inducers, in marathon runners before and just after running a marathon and their relationship with cardiac hypertrophy. Methodology: Single-blind prospective study of male athletes who ran the Santiago's marathon. A sedentary control group was included. All subjects underwent a standard transthoracic echocardiogram. CT1 and IGF-1 levels were determined in plasma obtained before (basal) and just after finishing (within 15 min) the marathon using ELISA assays. Results: Athletes had lower heart rates than controls, associated with greater myocardial hypertrophy, as determined by thickness of the heart's septum and posterior wall, and left atrial and ventricular volumes. Basal CT1 and IGF-1 levels were similar between athletes and sedentary controls. Marathon running increased the levels of these two hormones in a subgroup of athletes. Only the athletes who increased IGF-1 levels, but not CT1, had larger left and right ventricular volumes. Conclusion: IGF-1 acutely increased by exercise, but not CT1, was associated with the augmented ventricular volumes observed in athletes.

Impacto del Entrenamiento Respiratorio de Hiperpnea Isocápnica Voluntaria sobre el Costo Energético asociado a la Respiración inducido por Ejercicio Físico / Impact of Voluntary Isocapnic Hyperpnea training on the cost of breathing

Introducción. Determinar el efecto de ocho semanas de entrenamiento por hiperpnea isocápnica voluntaria (HIV) sobre el costo energético asociado a la respiración (COB) reflejado en los cambios en la oxigenación de los músculos intercostales (∆SmO2-m. intercostales) inducida por ejercicio físico de intensidad incremental. Métodos. Doce participantes físicamente activos fueron entrenados durante ocho semanas de HIV 3 días x semana, 12 minutos, al 60% de ventilación voluntaria máxima (VVM). En la semana previa y posterior al entrenamiento HIV se realizó un test cardiopulmonar (CPET) de intensidad incremental en cicloergómetro, durante esta prueba se registró la ∆SmO2-m. intercostales mediante el dispositivo MOXY®. El efecto de HIV sobre la ∆SmO2-m. intercostales se analizó mediante la prueba two-way mixed ANOVA considerando los factores (fase × tarea). Resultados. ∆SmO2-m.intercostales fue significativamente menor a partir del 30% (­5,0±4,7%; p<0.01) hasta el 100% (­10,6±12,8%; p<0.01) de la tarea luego de ocho semanas de HIV. Además, se reportó un aumento de la presión inspiratoria máxima (PIM)=16,5±11,4 cmH2O (p<0.01); y de la resistencia muscular respiratoria=106,6±149,0 s (p<0.01). El tiempo total de ejercicio aumentó en 106,6±149,0 s (p=0.04), así como la carga total en 10,50± 10,12 vatios (p<0.01). Conclusión. El HIV disminuye el COB inducido por ejercicio incremental asociado a un incremento en la performance física y de los músculos respiratorios. En futuros estudios se sugiere estudiar esta estrategia de entrenamiento analítico de los músculos respiratorios en usuarios con limitación física relacionada al aumento prematuro del COB.

Background. Objetive. To determine the effect of eight weeks of voluntary isocapnic hyperpnea (VIH) training on cost of breathing (COB) as reflected by intercostales muscles deoxygenation (∆SmO2-m. intercostales) induced by incremental-intensity physical exercise. Methods. Twelve physically active participants underwent eight weeks of VIH training, three days a week, for 12 minutes each session, at 60% of maximal voluntary ventilation (MVV). In the week before and after VIH training, a cardiopulmonary test (CPET) of incremental intensity was performed on a cycloergometer. During this test, intercostal ∆SmO2-m.intercostales was recorded using the MOXY® device. The effect of VIH on ∆SmO2-m.intercostales were analyzed using a two-way mixed ANOVA test considering the factors (phase × task). Results. ∆SmO2-m.intercostales significantly decreased from 30% (­5.0±4.7%; p<0.01) to 100% (­10.6±12.8%; p<0.01) of the task after eight weeks of VIH. Additionally, an increase in maximal inspiratory pressure (MIP) of 16.5±11.4 cmH2O (p<0.01) and respiratory muscle endurance of 106.6±149.0 s (p<0.01) was reported. Total exercise time increased by 106.6±149.0 s (p=0.04), as well as total workload by 10.50±10.12 watts (p<0.01). Conclusion. VIH reduces COB induced by incremental exercise and is associated with increased physical and respiratory muscle performance. Future studies should explore this respiratory muscle training strategy for individuals with physical limitations related to a premature increase in COB.

Terapia de alto flujo ¿Una alternativa en rehabilitación? / High flow therapy: An option to rehabilitation?

La pandemia por el virus SARS-COV2 que causó la enfermedad COVID-19 ha traído grandes desafíos al sistema de salud tanto a nivel nacional como mundial. En Chile, gracias al esfuerzo de organismos gubernamentales e instituciones privadas, los centros de salud se han equipado con distintos dispositivos de terapia ventilatoria (ventilación mecánica invasiva y no invasiva, y terapia de alto flujo de oxígeno mediante cánula nasal (TAF) con la finalidad de abarcar mayor atención de pacientes tras un periodo de crisis sanitaria que colapsó las redes de atención secundaria y terciaria de salud. En concordancia a esto, es interesante evaluar qué utilidad puede darse a estos equipos posterior a la pandemia, considerando que en varios centros de salud se duplicó o triplicó la disponibilidad de recursos técnicos. En este contexto, la TAF entrega efectos fisiológicos favorables y útiles en escenarios clínicos que implican aumento de las demandas ventilatorias, no sólo en condiciones de insuficiencia respiratoria hipoxémica aguda, sino en condiciones en donde el ejercicio aeróbico es un pilar fundamental, como es el caso de los diferentes programas de rehabilitación (cardiovascular, respiratorio, metabólico, etc.) incluidos como Garantías Explícitas de Salud (GES). Así, la incorporación de TAF en la rehabilitación pulmonar sería una opción adecuada en pacientes con disfunciones respiratorias crónicas, ampliando la cobertura sanitaria que estos programas tienen hoy en día.

The SARS-COV2 pandemic that caused the COVID-19 disease has brought significant challenges to the health system nationally and globally. In Chile, thanks to the efforts of government agencies and private institutions, health centres have been equipped with di-fferent ventilatory therapy devices (invasive and non-invasive mechanical ventilation, and high-flow oxygen therapy by nasal cannula (HFOT)), in order to cover more patient care after a period of a health crisis that collapsed secondary and tertiary health care networks. Accordingly, it is interesting to evaluate concerning what use can be given to these teams after the pandemic, even more considering that the availability of technical resources doubled or tripled in several health centres. In this context, HFOT provides favourable and useful physiological effects in clinical scenarios that involve increased ventilatory demands, not only in conditions of acute hypoxemic respiratory failure but also in conditions where aerobic exercise is a fundamental pillar, as is the case of the different rehabilitation programs (cardiovascular, respiratory, metabolic, etc.) included as Health Guarantees (Garantías Explicitas en Salud, GES). Thus, incorporating HFOT in pulmonary rehabilitation would be an appropriate option in patients with chronic respiratory dysfunctions, expanding the health coverage that these programs have today.