Browsing by Author "Viscor, Ginés"

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    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
    (2023) Espinosa Ramírez, Maximiliano; Riquelme Sánchez, Santiago; Araya, Felipe; Rodríguez, Guido; Figueroa Martínez, Fernanda; Gabrielli, Luigi; Viscor, Ginés; Reid, W. Darlene; Contreras-Briceño, Felipe; Pontificia Universidad Católica de Chile. Escuela de Medicina
    Tesis conducente al grado de Magíster en Investigación en Ciencias de la Salud. Abstract: 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 (∆SmO2-m. intercostales) and vastus lateralis (∆SmO2-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 ∆SmO2 (the change from baseline to end of test) of intercostal and vastus lateralis muscles. After RMT, both groups showed decreased ∆SmO2-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 VO2-peak absolute values than VIH (mean ∆ 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.
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    Humidity prevents the exercise-induced formation of hydrogen peroxide and nitrite in exhaled breath condensate in recreational cyclists
    (2020) Contreras Briceño, Felipe; Espinosa Ramírez, Maximiliano; Viscor, Ginés; Araneda, Oscar F.
    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 (V) over dotO(2)-max. test, 49.3 +/- 7.6 mL center dot min(-1)center dot 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 x 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.
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    Monitoring Changes in Oxygen Muscle during Exercise with High-Flow Nasal Cannula Using Wearable NIRS Biosensors
    (2023) Contreras Briceño, Felipe; Espinosa Ramírez, Maximiliano; Rivera Greene, Augusta; Guerra Venegas, Camila Isidora; Lungenstrass Poulsen, Antonia Isabel; Villagra Reyes, Victoria Paz; Caulier Cisterna, Raúl; Araneda, Oscar F.; Viscor, Ginés
    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.
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    Oxigenación en músculos respiratorios y locomotores durante el ejercicio máximo en doscorredores de maratón
    (2020) Contreras Briceño, Felipe; Espinosa Ramirez,Maximiliano Andres; Cerda Vasquez Francisco Ignacio; Carrasco, Miguel; Henriquez Llambias Diego Andres; Hevia Ramos, Gonzalo Benjamin; Araneda, Oscar; Viscor, Ginés
    Un elevado trabajo respiratorio (work of breathing, WOB) asociado a la hiperventilación pulmonar durante el ejercicio físico puede limitar el rendimiento deportivo en corredores de maratón. Evaluar los cambios del WOB durante el ejercicio físico máximo, como es la prueba de consumo de oxígeno (VO2-máx), permite conocer la intensidad de ejercicio a la cual el WOB limita la entrega de nutrientes y oxígeno en músculos periféricos implicados en la locomoción. La evaluación no invasiva de la saturación de oxígeno a nivel muscular (SmO2) por medio de la interpretación de ondas cercanas al rango infrarrojo (Near Infrared Spectroscopy, NIRS) es una método novedoso y útil para cuantificar el trabajo muscular, aplicable tanto en musculatura intercostal (SmO2-m.intercostales) para el WOB, como en musculatura locomotora (SmO2-m.vastus laterallis) para la carga periférica. Así, a medida que aumenta la intensidad del esfuerzo físico es esperable una mayor disminución en SmO2; sin embargo, se desconoce como la estrategia ventilatoria usada para alcanzar la hiperventilación pulmonar afecta la SmO2 de estos grupos musculares, cuyo trabajo muscular los afecta recíprocamente a través del reflejo metabólico. Como caso clínico, presentamos los cambios en SmO2-m.intercostales (WOB) y locomotora (SmO2-m.vastus laterallis) durante la prueba de VO2-máx. en dos corredores competitivos demaratón de similares características antropométricas, capacidad física, régimen de entrenamiento e historial deportivo. El objetivo es entregar nueva información que muestre cómo la estrategia ventilatoria adoptada durante el ejercicio puede limitar el trabajo muscular periférico realizado.
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    Swimming versus running : effects on exhaled breath condensate pro-oxidants and pH
    (2018) Araneda, Oscar F.; Contreras Briceño, Felipe; Cavada, Gabriel; Viscor, Ginés
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    Systemic and Pulmonary Inflammation/Oxidative Damage: Implications of General and Respiratory Muscle Training in Chronic Spinal-Cord-Injured Patients
    (2023) Araneda, Oscar F.; Rosales-Antequera, Cristián; Contreras Briceño, Felipe; Tuesta, Marcelo; Rossi-Serrano, Rafael; Magalhães, José; Viscor, Ginés
    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.