Browsing by Author "Viscor, Gines"

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    Determination of the Respiratory Compensation Point by Detecting Changes in Intercostal Muscles Oxygenation by Using Near-Infrared Spectroscopy
    (MDPI, 2022) Contreras Briceño, Felipe; Espinosa Ramírez, Maximiliano; Keim Bagnara, Vicente; Carreño Roman, Matías Ignacio; Rodríguez Villagra, Rafael Alejandro; Villegas Belmar, Fernanda; Viscor, Gines; Gabrielli Nervi, Luigi Arnaldo; Andia, Marcelo E.; Araneda, Oscar F.; Hurtado, Daniel E.
    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) over dotO(2)-max 58.4 +/- 8.1 mL.kg(-1).min(-1)) were evaluated in a cycle ergometer during the maximal oxygen-uptake test ((V) over dotO(2)-max), while lung ventilation ((V) over dotE), power output (watts, W) and SmO2 mantercostales were measured. RCP was determined by visual method (RCPvisual : changes at ventilatory equivalents ((V) over dotE.CO2-1, (V) over dotE.(V) over dotO(2)(-1)) and end-tidal respiratory pressure (PetO(2), PetCO(2)) and NIRS method (RCP NIRS : breakpoint of fall in SmO2 m.intercostales). During exercise, SmO2 m.intercostales decreased continuously showing a higher decrease when (V) over dotE increased abruptly. A good agreement between methods used to determine RCP was found (visual vs NIRS) at %(V) over dotO(2)-max, (V) over dotO(2), (V) over dotE, 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.
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    Intercostal Muscles Oxygenation and Breathing Pattern during Exercise in Competitive Marathon Runners
    (Wiley, 2021) Contreras Briceño, Felipe; Espinosa Ramirez, Maximiliano Andres; Moya Gallardo, Eduardo Sebastián; Fuentes Kloss, Rodrigo Alejandro; Gabrielli Nervi, Luigi Arnaldo; Araneda, Oscar F.; Viscor, Gines
    The study aimed to evaluate the association between the changes in ventilatory variables (tidal volume (Vt), respiratory rate (RR) and lung ventilation (VE)) and deoxygenation of m.intescostales (Delta SmO2-m.intercostales) during a maximal incremental exercise in 19 male high-level competitive marathon runners. The ventilatory variables and oxygen consumption (VO2) were recorded breath-by-breath by exhaled gas analysis. A near-infrared spectroscopy device (MOXY (R)) 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 (R) 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 ASmO(2)-m.intercostales correlated with VO2-peak (r = 0.65; p = 0.002) and the increase of VE (r = 0.78; p = 0.001), RR (r = 0.54; p = 0.001), but not Vt (p = 0.210). The interaction of factors (muscles x 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 VO2-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.
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    Sex-Differences in the Oxygenation Levels of Intercostal and Vastus Lateralis Muscles During Incremental Exercise
    (Wiley, 2021) Espinosa Ramírez, Maximiliano Andrés; Moya Gallardo, Eduardo Sebastián; Araya Román, Felipe Andrés; Riquelme Sánchez, Santiago Martín; Rodríguez García, Guido Hernán Antonio; Reid, W. Darlene; Viscor, Gines; Araneda, Oscar F.; Gabrielli Nervi, Luigi Arnaldo; Contreras Briceño, Felipe
    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(R) devices on the m.intercostales and m.vastus lateralis. A two-way ANOVA (sex x 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 Delta SmO2-m.intercostales normalized to V.E (L.min(-1)) (p < 0.001), whereas men had a higher level of Delta SmO2-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.