scholarly journals Effect of expiratory loaded breathing during moderate exercise on intercostal muscle oxygenation

2020 ◽  
Vol 15 ◽  
Author(s):  
Quentin Bretonneau ◽  
Aurélien Pichon ◽  
Claire De Bisschop

Background: In patients with obstructive lung disease, maintaining adequate ventilation during exercise may require greater contraction of the respiratory muscles, which may lead to a compression of muscle capillaries. Furthermore, dynamic hyperinflation (DH) is frequent during exercise in these patients, as it allows to reach higher expiratory flows and to satisfy respiratory demand. However, in such situation, intercostal muscles are likely to be stretched, which could affect the diameter of their capillaries. Thus, in a context of high level of expiratory resistance, intercostal muscle oxygenation may be disturbed during exercise, especially if DH occurs.Methods: Twelve participants (22±2 years) performed two sessions of moderate exercise (20 min) by breathing freely with and without a 20-cmH2O expiratory threshold load (ETL). Tissue saturation index (TSI) and concentration changes from rest (∆) in oxygenated ([O2Hb]) and total haemoglobin ([tHb]) were measured in the seventh intercostal space using near-infrared spectroscopy. Respiratory, metabolic and cardiac variables were likewise recorded.Results: Throughout exercise, dyspnea was higher and TSI was lower in ETL condition than in control (p<0.01). After a few minutes of exercise, ∆ [O2Hb] was also lower in ETL condition, as well as ∆ [tHb], when inspiratory capacity started to be reduced (p<0.05). Changes in [O2Hb] and dyspnea were correlated with changes in expiratory flow rate (Vt/Te) (r = -0.66 and 0.66. respectively; p<0.05).Conclusion: During exercise with ETL, impaired muscle oxygenation could be due to a limited increase in blood volume resulting from strong muscle contraction and/or occurrence of DH.

2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
P Chatzinikolaou ◽  
N Cornelis ◽  
J Claes ◽  
R Buys ◽  
I Fourneau ◽  
...  

Abstract Funding Acknowledgements Type of funding sources: None. Background. Intermittent claudication (IC) is characterized by a cramp-like pain during walking caused by insufficient blood flow to the lower limbs during exercise. The walking impairment caused by IC can lead to a vicious cycle of physical inactivity, decreased quality of life and progression of cardiovascular risk factors. Although current evidence supports the benefits of walking training to increase walking capacity, little is known about its effect on muscle oxygenation in this population. Purpose. The aim of this study was to investigate the effects of a hybrid 12-week walking program (combined center- and home-based walking) on muscle oxygenation of IC patients. Methods. Thirty-seven patients with IC were enrolled of which 33 completed follow-up measurements (age 71 ± 9 yrs, body mass index 26 ± 4 kg/m2, ankle brachial index (ABI) 0.7 ± 0.2) after the 12-week intervention. Outcome measures were pain-free walking capacity (PFWC), maximal walking capacity (MWC) and calf muscle oxygenation, respectively evaluated using a submaximal treadmill test, a Gardner treadmill test and near-infrared spectroscopy (NIRS). Results. After the 12-week intervention, significantly higher values (reported as median and interquartiles) for PFWC (162 m [122, 217] to 272 m [150, 401]; p &lt; 0.001) and MWC (458 m [260, 638] to 611 m [333, 840]; p &lt; 0.001) were observed. As shown in Table 1, NIRS data measured during the submaximal walking test showed an increased availability of oxygenated hemoglobin (p = 0.048) and decreased deoxyhemoglobin (p = 0.013), while total hemoglobin remained unchanged after the 12-week intervention. During the Gardner test, time to reach minimum tissue saturation index (TSI%) increased (p &lt; 0.001), yet no change was noted on minimum TSI during exercise, despite increased MWC. Despite a trend towards faster recovery times, no significant changes were observed after the 12-week intervention. Conclusion. Hybrid walking exercise therapy improves deoxygenation kinetics and walking capacity in IC patients. Increased availability of oxygenated hemoglobin might underly the improvement in walking capacity.


2016 ◽  
Vol 120 (7) ◽  
pp. 792-800 ◽  
Author(s):  
Poonam B. Jaiswal ◽  
Paul W. Davenport

A respiratory load compensation response is characterized by increases in activation of primary respiratory muscles and/or recruitment of accessory respiratory muscles. The contribution of the external intercostal (EI) muscles, which are a primary respiratory muscle group, during normal and loaded breathing remains poorly understood in conscious animals. Consciousness has a significant role on modulation of respiratory activity, as it is required for the integration of behavioral respiratory responses and voluntary control of breathing. Studies of respiratory load compensation have been predominantly focused in anesthetized animals, which make their comparison to conscious load compensation responses challenging. Using our established model of intrinsic transient tracheal occlusions (ITTO), our aim was to evaluate the motor behavior of EI muscles during normal and loaded breathing in conscious rats. We hypothesized that 1) conscious rats exposed to ITTO will recruit the EI muscles with an increased electromyogram (EMG) activation and 2) repeated ITTO for 10 days would potentiate the baseline EMG activity of this muscle in conscious rats. Our results demonstrate that conscious rats exposed to ITTO respond by recruiting the EI muscle with a significantly increased EMG activation. This response to occlusion remained consistent over the 10-day experimental period with little or no effect of repeated ITTO exposure on the baseline ∫EI EMG amplitude activity. The pattern of activation of the EI muscle in response to an ITTO is discussed in detail. The results from the present study demonstrate the importance of EI muscles during unloaded breathing and respiratory load compensation in conscious rats.


Author(s):  
Larissa Sinhorim ◽  
Mayane Amorim ◽  
Laureani Jaques Torres ◽  
Janaína Wagner ◽  
Nathália Tiepo Niza ◽  
...  

Background: Myofascial Reorganization (MFR) is a physiotherapy technique that mixes myofascial pressures and slips and has been used as a simple and non-invasive method that readjusts soft tissues, as well as myofascial adhesions and contractures that may cause decreased blood supply and consequently of physical activity. Objective: To verify if the MFR alters the tissue oxygenation of the trapezius muscle (TM) in subjects without the pain symptom in the evaluation day. Methods: The sample consisted of eight subjects with a mean age of 23 (± 6) years and a body mass index of 23.2 (±15.0) kg.m-2. Changes in muscle oxygenation were measured by near infrared spectroscopy (NIRS) (Portamon, Artinis, the Netherlands) in TM before and after 15 minutes of intervention. The proposed MFR protocol lasted approximately 10 minutes and consisted of pressures, stretching and myofascial slippage of the upper, middle and lower TM fibers. Data normality was performed using the Shapiro Wilk test and due to the parametric nature of the data, the paired t-test was used for pre and post intervention comparison. Results: There was a significant increase in the tissue saturation index (TSI) in the trapezius muscle (80.7±2.7% vs. 89.4±4.6%; p= 0.002) in the pre and post intervention comparison. The pre-post variation delta of oxyhemoglobin - O2 Hb (8.1±11.2 g/dL), deoxyhemoglobin - HHb (-0.72±1.6 g/dL) and total hemoglobin - tHB (7.4±12.3 g/dL) showed no significant difference. However, there was an increase in O2 Hb, tHB levels and a decrease in HHb. Conclusion: The findings showed that the MFR applied on trapezius muscle increased the TSI, which reflects on peripheral muscle oxygenation in subjects without pain in the day of evaluation.


2021 ◽  
pp. 684-689
Author(s):  
Keiichi Yamaguchi ◽  
Tomohiro Imai ◽  
Haruka Yatsutani ◽  
Kazushige Goto

The present study investigated the effects of a combined hot and hypoxic environment on muscle oxygenation during repeated 15-s maximal cycling sprints. In a single-blind, cross-over study, nine trained sprinters performed three 15-s maximal cycling sprints interspersed with 7-min passive recovery in normoxic (NOR; 23℃, 50%, FiO2 20.9%), normobaric hypoxic (HYP; 23℃, FiO2 14.5%), and hot normobaric hypoxic (HH; 35℃, FiO2 14.5%) environments. Relative humidity was set to 50% in all trials. The vastus lateralis muscle oxygenation was evaluated during exercise using near-infrared spectroscopy. The oxygen uptake (VO2) and arterial oxygen saturation (SpO2) were also monitored. There was no significant difference in peak or mean power output among the three conditions. The reduction in tissue saturation index was significantly greater in the HH (-17.0 ± 2.7%) than in the HYP (-10.4 ± 2.8%) condition during the second sprint (p < 0.05). The average VO2 and SpO2 were significantly lower in the HYP (VO2 = 980 ± 52 mL/min, SpO2 = 82.9 ± 0.8%) and HH (VO2 = 965 ± 42 mL/min, SpO2 = 83.2 ± 1.2%) than in the NOR (VO2 = 1149 ± 40 mL/min, SpO2 = 90.6 ± 1.4%; p < 0.05) condition. In conclusion, muscle oxygen saturation was reduced to a greater extent in the HH than in the HYP condition during the second bout of three 15-s maximal cycling sprints, despite the equivalent hypoxic stress between HH and HYP.


2019 ◽  
Author(s):  
Shih-Chieh Chang ◽  
Alessandra Adami ◽  
Hsin-Chin Lin ◽  
Yin-Chou Lin ◽  
Carl P.C. Chen ◽  
...  

AbstractIt remains unclear whether the number of total bouts to limitation (Blim) in high-intensity interval testing (HIIT) differs among individuals, no matter if performed at the same relative intensity. This study aimed to explore the physiologic factors determining tolerance to effort during a HIIT. Forty-seven female participants (15-28 years old) were included: 23 athletes from Taiwan national or national reserve teams, and 24 moderately-active female. Each participant underwent maximal incremental (INC; modified-Bruce protocol) cardiopulmonary exercise testing and HIIT on treadmill, on separate days. HIIT protocol alternated a 1-min effort at 120% of the maximal speed and the same slope reached at the end of INC, with a 1-min rest, until volitional exhaustion. Gas-exchanges, and muscle oxygenation at right vastus lateralis by near-infrared spectroscopy, were continuously recorded. Additionally, bioelectrical impedance was utilized for body composition analysis. The result showed that Blim differed greatly (range: 2.6 to 12) among participants. Stepwise regression revealed that Blim was determined primarily by oxygen consumption (VO2) and heart rate (HR) at second-minute recovery; and, muscle tissue saturation index at peak of INC (R=0.644). Also, age and percent body fat were linearly correlated with Blim (adjusted R=−0.475, −0.371, p<0.05). Therefore, HIIT performance is determined by fast recovery of VO2 and HR, rather than maximal VO2 or muscle oxygenation recovery. Moreover, capacity to sustain a HIIT declines with age since as early as late adolescent. Further investigations on which factors should be manipulated to further improve athletes performance are warrant.


Healthcare ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 412
Author(s):  
Li Cong ◽  
Hideki Miyaguchi ◽  
Chinami Ishizuki

Evidence shows that second language (L2) learning affects cognitive function. Here in this work, we compared brain activation in native speakers of Mandarin (L1) who speak Japanese (L2) between and within two groups (high and low L2 ability) to determine the effect of L2 ability in L1 and L2 speaking tasks, and to map brain regions involved in both tasks. The brain activation during task performance was determined using prefrontal cortex blood flow as a proxy, measured by functional near-infrared spectroscopy (fNIRS). People with low L2 ability showed much more brain activation when speaking L2 than when speaking L1. People with high L2 ability showed high-level brain activation when speaking either L2 or L1. Almost the same high-level brain activation was observed in both ability groups when speaking L2. The high level of activation in people with high L2 ability when speaking either L2 or L1 suggested strong inhibition of the non-spoken language. A wider area of brain activation in people with low compared with high L2 ability when speaking L2 is considered to be attributed to the cognitive load involved in code-switching L1 to L2 with strong inhibition of L1 and the cognitive load involved in using L2.


1997 ◽  
Vol 82 (4) ◽  
pp. 1119-1125 ◽  
Author(s):  
G. S. Supinski ◽  
D. Stofan ◽  
R. Ciufo ◽  
A. Dimarco

Supinski, G. S., D. Stofan, R. Ciufo, and A. DiMarco. N-acetylcysteine administration alters the response to inspiratory loading in oxygen-supplemented rats. J. Appl. Physiol. 82(4): 1119–1125, 1997.—Based on recent studies, it has been suggested that free radicals are elaborated in the respiratory muscles during strenuous contractions and contribute to the development of muscle fatigue. If this theory is correct, then it should be possible to attenuate the development of diaphragm fatigue and/or delay the onset of respiratory failure during loaded breathing by administering a free radical scavenger. The purpose of the present experiment was, therefore, to examine the effect of N-acetylcysteine (NAC), a free radical scavenger and glutathione precursor, on the evolution of respiratory failure in decerebrate unanesthetized rats breathing against a large inspiratory resistive load. We compared the inspiratory volume and pressure generation over time in animals pretreated with either saline or NAC (150 mg/kg) and then loaded until respiratory arrest. After arrest, the diaphragm was excised, and samples were assayed for reduced (GSH) and oxidized glutathione. As a control, we also assessed respiratory function and glutathione concentrations in groups of nonloaded saline- and NAC-treated animals. We found that NAC-treated animals were able to tolerate loading better than the saline-treated group, maintaining higher inspiratory pressures and sustaining higher inspired volumes. Administration of NAC also increased the time that animals could tolerate loading before the development of respiratory arrest. In addition, although saline-treated loaded animals had significant reductions in diaphragmatic GSH levels compared with unloaded controls, the magnitude of this reduction was blunted by NAC administration (i.e., GSH averaged 965 ± 113, 568 ± 83, 907 ± 39, and 784 ± 61 nmol/g for unloaded-saline, loaded-saline, unloaded-NAC, and loaded-NAC groups, P< 0.05, with the value for the loaded-saline group lower than the values for the two unloaded groups; GSH for the loaded-NAC group was not different, however, from unloaded controls). These data demonstrate that administration of NAC, a free radical scavenger, slows the rate of development of respiratory failure during inspiratory resistive loading.


2015 ◽  
Vol 308 (2) ◽  
pp. R105-R111 ◽  
Author(s):  
Wladimir M. Medeiros ◽  
Mari C. T. Fernandes ◽  
Diogo P. Azevedo ◽  
Flavia F. M. de Freitas ◽  
Beatriz C. Amorim ◽  
...  

Central cardiorespiratory and gas exchange limitations imposed by chronic obstructive pulmonary disease (COPD) impair ambulatory skeletal muscle oxygenation during whole body exercise. This investigation tested the hypothesis that peripheral factors per se contribute to impaired contracting lower limb muscle oxygenation in COPD patients. Submaximal neuromuscular electrical stimulation (NMES; 30, 40, and 50 mA at 50 Hz) of the quadriceps femoris was employed to evaluate contracting skeletal muscle oxygenation while minimizing the influence of COPD-related central cardiorespiratory constraints. Fractional O2 extraction was estimated by near-infrared spectroscopy (deoxyhemoglobin/myoglobin concentration; deoxy-[Hb/Mb]), and torque output was measured by isokinetic dynamometry in 15 nonhypoxemic patients with moderate-to-severe COPD (SpO2 = 94 ± 2%; FEV1 = 46.4 ± 10.1%; GOLD II and III) and in 10 age- and gender-matched sedentary controls. COPD patients had lower leg muscle mass than controls (LMM = 8.0 ± 0.7 kg vs. 8.9 ± 1.0 kg, respectively; P < 0.05) and produced relatively lower absolute and LMM-normalized torque across the range of NMES intensities ( P < 0.05 for all). Despite producing less torque, COPD patients had similar deoxy-[Hb/Mb] amplitudes at 30 and 40 mA ( P > 0.05 for both) and higher deoxy-[Hb/Mb] amplitude at 50 mA ( P < 0.05). Further analysis indicated that COPD patients required greater fractional O2 extraction to produce torque (i.e., ↑Δdeoxy-[Hb/Mb]/torque) relative to controls ( P < 0.05 for 40 and 50 mA) and as a function of NMES intensity ( P < 0.05 for all). The present data obtained during submaximal NMES of small muscle mass indicate that peripheral abnormalities contribute mechanistically to impaired contracting skeletal muscle oxygenation in nonhypoxemic, moderate-to-severe COPD patients.


2019 ◽  
Vol 261 ◽  
pp. 24-30
Author(s):  
Quentin Bretonneau ◽  
Aurélien Pichon ◽  
Claire de Bisschop

Sign in / Sign up

Export Citation Format

Share Document