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Traditional Nostril Yoga Breathing Practices and Oxygen Consumption: A Randomized, Cross-over Study.International Journal of Yoga 2024Traditional yoga texts describe "cross nostril breathing," with inhalation and exhalation through different nostrils. Previous research reported no clear differences in...
BACKGROUND
Traditional yoga texts describe "cross nostril breathing," with inhalation and exhalation through different nostrils. Previous research reported no clear differences in oxygen consumption during uninostril breathing (i.e., inhalation and exhalation through the same nostril), hence not supporting right and left uninostril breathing as activating or relaxing, respectively, with no research on oxygen consumed in "cross nostril breathing."
METHODS
Oxygen consumed during "cross nostril breathing" was measured in healthy participants ( = 47, males, 26.3 ± 6.4 years). Five sessions (viz., right nostril inspiration yoga breathing [RNIYB], left nostril inspiration yoga breathing [LNIYB], alternate nostril yoga breathing [ANYB], breath awareness (BAW), and quiet rest (QR) were conducted on separate days in random order. Sessions were 33 min in duration with pre, during, and post states.
RESULTS
Volume of oxygen consumed (VO) and carbon dioxide eliminated (VCO) increased during RNIYB (9.60% in VO and 23.52% in VCO), LNIYB (9.42% in VO and 21.20% in VCO) and ANYB (10.25% in VO and 22.72% in VCO) with no significant change in BAW and QR. Diastolic blood pressure decreased during BAW and QR and after all five sessions ( < 0.05; in all cases). All comparisons were with the respective preceding state.
CONCLUSION
During the three yoga breathing practices, the volume of oxygen consumed increased irrespective of the nostril breathed through, possibly associated with (i) conscious regulation of the breath; (ii) attention directed to the breath, and (iii) "respiration-locked cortical activation." Restriction of the study to males reduces the generalizability of the findings.
PubMed: 38899139
DOI: 10.4103/ijoy.ijoy_248_23 -
Journal of Physiotherapy Apr 2024What are the effects of different types of exercise treatments on oxygen consumption, quality of life and mortality in people with coronary heart disease? (Meta-Analysis)
Meta-Analysis
QUESTION
What are the effects of different types of exercise treatments on oxygen consumption, quality of life and mortality in people with coronary heart disease?
DESIGN
Systematic review with network meta-analysis of randomised controlled trials.
PARTICIPANTS
Adults with coronary heart disease.
INTERVENTION
Exercise interventions including aerobic (continuous or high-intensity interval) training, resistance training, respiratory muscle exercises, water-based exercises, yoga, Tai chi, Qigong exercises and a combination of different types of exercise.
OUTCOME MEASURES
Oxygen consumption, quality of life and mortality.
RESULTS
This review included 178 randomised controlled trials with 19,143 participants. Several exercise interventions improved peak oxygen consumption (mL/kg/min): high-intensity interval training (MD 4.5, 95% CI 3.7 to 5.4); combined water-based exercises and moderate-intensity continuous training (MD 3.7, 95% CI 1.3 to 6.0); combined aerobic and resistance exercise (MD 3.4, 95% CI 2.5 to 4.3); water-based exercises (MD 3.4, 95% CI 0.6 to 6.2); combined respiratory muscle training and aerobic exercise (MD 3.2, 95% CI 0.6 to 5.8); Tai chi (MD 3.0, 95% CI 1.0 to 5.0); moderate-intensity continuous training (MD 3.0, 95% CI 2.3 to 3.6); high-intensity continuous training (MD 2.7, 95% CI 1.6 to 3.8); and resistance training (MD 2.2, 95% CI 0.6 to 3.7). Quality of life was improved by yoga (SMD 1.5, 95% CI 0.5 to 2.4), combined aerobic and resistance exercise (SMD 1.2, 95% CI 0.6 to 1.7), moderate-intensity continuous training (SMD 1.1, 95% CI 0.6 to 1.6) and high-intensity interval training (SMD 0.9, 95% CI 0.1 to 1.6). All-cause mortality was reduced by continuous aerobic exercise (RR 0.67, 95% CI 0.53 to 0.86) and combined aerobic and resistance exercise (RR 0.58, 95% CI 0.36 to 0.94). Continuous aerobic exercise also reduced cardiovascular mortality (RR 0.56, 95% CI 0.42 to 0.74).
CONCLUSION
People with coronary heart disease may use a range of exercise modalities to improve oxygen consumption, quality of life and mortality.
REGISTRATION
PROSPERO CRD42022344545.
Topics: Adult; Humans; Quality of Life; Network Meta-Analysis; Exercise Therapy; Coronary Disease; Water
PubMed: 38503676
DOI: 10.1016/j.jphys.2024.02.018 -
European Journal of Applied Physiology Mar 2024To determine the effects of load carriage in normoxia and normobaric hypoxia on ventilatory responses, hemodynamics, tissue oxygenation, and metabolism.
PURPOSE
To determine the effects of load carriage in normoxia and normobaric hypoxia on ventilatory responses, hemodynamics, tissue oxygenation, and metabolism.
METHODS
Healthy males (n = 12) completed 3 randomly ordered baseline graded exercise tests in the following conditions: (1) unloaded normoxic (U: FO = 20.93%), (2) loaded (~ 30 kg) normoxic (LN), and (3) loaded hypoxic simulating ~ 3650 m (LH: FO = ~ 13%). Thereafter, experimental exercise trials were completed in quasi-randomized order (i.e., U completed first) consisting of 3 × 10 min of walking (separated by 5 min seated rest) with stages matched with the U condition (in ascending order) for relative intensity, absolute oxygen consumption ([VO]; 1.7 L min), and walking speed (1.45 ± 0.15 m s).
RESULTS
Load carriage increased perceived exertion and reduced VO (LN: - 7%; LH: - 32%; p < 0.05). At matched VO, stroke volume and tidal volume were reduced and maintained with LN and LH vs. U, respectively (p < 0.05). Increases in cardiac output and minute ventilation at matched VO (with LH) and speed (with LN and LH), were primarily accomplished via increases in heart rate and breathing frequency (p < 0.05). Cerebral oxygenated hemoglobin (OHHb) was increased at all intensities with LN, but deoxygenated hemoglobin and total hemoglobin were increased with LH (p < 0.05). Muscle oxygen kinetics and substrate utilization were similar between LN and U, but LH increased CHO dependence and reduced muscle OHHb at matched speed (p < 0.05).
CONCLUSION
Load carriage reduces cardiorespiratory efficiency and increases physiological strain, particularly in hypoxic environments. Potential load carriage-induced alterations in cerebral blood flow may increase the risk for altitude illnesses and requires further study.
Topics: Male; Humans; Hypoxia; Respiration; Exercise; Oxygen Consumption; Oxygen; Hemoglobins
PubMed: 37740748
DOI: 10.1007/s00421-023-05320-2 -
The EMBO Journal Jun 2024Every day, cells face hypoxic conditions without anyone realizing it. New research by Tan et al (2024) reveals that differentiated cells in standard cell culture medium...
Every day, cells face hypoxic conditions without anyone realizing it. New research by Tan et al (2024) reveals that differentiated cells in standard cell culture medium volumes experience local hypoxia, with significant implications for cell metabolism and beyond, demanding a careful understanding and control of oxygen levels in in vitro experiments to better translate them in vivo.
Topics: Oxygen; Humans; Altitude
PubMed: 38698216
DOI: 10.1038/s44318-024-00105-5 -
Perfusion Jul 2023Isolated limb perfusion (ILP) is a regional surgical treatment for localized metastatic disease. High doses of chemotherapeutic agents are administered within an...
BACKGROUND
Isolated limb perfusion (ILP) is a regional surgical treatment for localized metastatic disease. High doses of chemotherapeutic agents are administered within an extracorporeal circulated isolated extremity, treating the metastasis, while systemic toxicity is avoided. To our knowledge, indexed oxygen supply/demand relationship during ILP has not previously been described. Our aim was to measure and describe oxygen metabolism, specifically oxygen delivery, consumption, and extraction, in an isolated leg/arm during ILP. Also investigate whether invasive oxygenation measurement during ILP correlates and can be used interchangeable with the non-invasive method, near infrared spectroscopy (NIRS).
METHODS
Data from 40 patients scheduled for ILP were included. At six time points blood samples were drawn during the procedure. DO2, VO2, and O2ER were calculated according to standard formulas. NIRS and hemodynamics were recorded every 10 min.
RESULTS
For all observations, the mean of DO2 was 190±59 ml/min/m2, VO2 was 35±8 ml/min/m2, and O2ER was 21±8%. VO2 was significantly higher in legs compared to arms (38±8 vs. 29±7 ml/min/m2, p=0.02). Repeated measures showed a significant decrease in DO2 in legs (209±65 to 180±66 ml/min/m2, p=<0.01) and in arms (252±72 to 150±57 ml/min/m2, p=<0.01). Significant increase in O2ER in arms was also found (p=0.03). Significant correlation was detected between NIRS and venous extremity oxygen saturation (SveO2) (rrm=0.568, p=<. 001, 95% CI 0.397-0.701). When comparing SveO2 and NIRS using a Bland-Altman analysis, the mean difference (bias) was 8.26±13.03 (p=<. 001) and the limit of agreement was - 17.28-33.09, with an error of 32.5%.
CONCLUSION
DO2 above 170 ml/min/m2 during ILP kept O2ER below 30% for all observations. NIRS correlates significant to SveO2; however, the two methods do not agree sufficiently to work interchangeable. Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT04460053 and NCT03073304.
Topics: Humans; Extracorporeal Circulation; Extremities; Hemodynamics; Oxygen; Oxygen Consumption; Perfusion
PubMed: 35575302
DOI: 10.1177/02676591221093201 -
Frontiers in Physiology 2023To maintain atrial function, ATP supply-to-demand matching must be tightly controlled. Ca can modulate both energy consumption and production. In light of evidence...
To maintain atrial function, ATP supply-to-demand matching must be tightly controlled. Ca can modulate both energy consumption and production. In light of evidence suggesting that Ca affects energetics through "push" (activating metabolite flux and enzymes in the Krebs cycle to push the redox flux) and "pull" (acting directly on ATP synthase and driving the redox flux through the electron transport chain and increasing ATP production) pathways, we investigated whether both pathways are necessary to maintain atrial ATP supply-to-demand matching. Rabbit right atrial cells were electrically stimulated at different rates, and oxygen consumption and flavoprotein fluorescence were measured. To gain mechanistic insight into the regulators of ATP supply-to-demand matching in atrial cells, models of atrial electrophysiology, Ca cycling and force were integrated with a model of mitochondrial Ca and a modified model of mitochondrial energy metabolism. The experimental results showed that oxygen consumption increased in response to increases in the electrical stimulation rate. The model reproduced these findings and predicted that the increase in oxygen consumption is associated with metabolic homeostasis. The model predicted that Ca must act both in "push" and "pull" pathways to increase oxygen consumption. In contrast to ventricular trabeculae, no rapid time-dependent changes in mitochondrial flavoprotein fluorescence were measured upon an abrupt change in workload. The model reproduced these findings and predicted that the maintenance of metabolic homeostasis is due to the effects of Ca on ATP production. Taken together, this work provides evidence of Ca "push" and "pull" activity to maintain metabolic homeostasis in atrial cells.
PubMed: 37528893
DOI: 10.3389/fphys.2023.1231259 -
Critical Care (London, England) Jul 2023Several noninvasive ventilatory supports rely in their design on high oxygen consumption which may precipitate oxygen shortage, as experienced during the COVID-19...
BACKGROUND
Several noninvasive ventilatory supports rely in their design on high oxygen consumption which may precipitate oxygen shortage, as experienced during the COVID-19 pandemic. In this bench-to-bedside study, we assessed the performance of a new continuous positive airway pressure (CPAP) device integrating a large reservoir ("Bag-CPAP") designed to minimize oxygen consumption, and compared it with other CPAP devices.
METHODS
First, a bench study compared the performances of Bag-CPAP and four CPAP devices with an intensive care unit ventilator. Two FiO targets (40-60% and 80-100%) at a predefined positive end expiratory pressure (PEEP) level between 5 and 10 cm HO were tested and fraction of inspired oxygen (FiO) and oxygen consumption were measured. Device-imposed work of breathing (WOB) was also evaluated. Second, an observational clinical study evaluated the new CPAP in 20 adult patients with acute respiratory failure in two hospitals in France. Actual FiO, PEEP, peripheral oxygen saturation, respiratory rate, and dyspnea score were assessed.
RESULTS
All six systems tested in the bench study reached the minimal FiO target of 40% and four reached at least 80% FiO while maintaining PEEP in the predefined range. Device-delivered FiO/consumed oxygen ratio was the highest with the new reservoir-based CPAP irrespective of FiO target. WOB induced by the device was higher with Bag-CPAP. In the clinical study, Bag-CPAP was well tolerated and could reach high (> 90%) and moderate (> 50%) FiO with an oxygen flow rate of 15 [15-16] and 8 [7-9] L/min, respectively. Dyspnea score improved significantly after introduction of Bag-CPAP, and SpO increased.
CONCLUSIONS
In vitro, Bag-CPAP exhibited the highest oxygen saving properties albeit had increased WOB. It was well accepted clinically and reduced dyspnea. Bag-CPAP may be useful to treat patients with acute respiratory failure in the field, especially when facing constraints in oxygen delivery.
Topics: Adult; Humans; Continuous Positive Airway Pressure; COVID-19; Dyspnea; Oxygen; Oxygen Consumption; Pandemics; Respiratory Insufficiency
PubMed: 37403149
DOI: 10.1186/s13054-023-04542-2 -
European Journal of Applied Physiology Nov 2023To compare physiological responses between a self-paced 4-min double-poling (DP) time-trial (TT) versus a 4-min diagonal-stride (DS) time-trial (TT). The relative...
PURPOSE
To compare physiological responses between a self-paced 4-min double-poling (DP) time-trial (TT) versus a 4-min diagonal-stride (DS) time-trial (TT). The relative importance of peak oxygen uptake ([Formula: see text]O), anaerobic capacity, and gross efficiency (GE) for projection of 4-min TT and TT roller-skiing performances were also examined.
METHODS
Sixteen highly trained male cross-country skiers performed, in each sub-technique on separate occasions, an 8 × 4-min incremental submaximal protocol, to assess individual metabolic rate (MR) versus power output (PO) relationships, followed by a 10-min passive break and then the TT or TT, with a randomized order between sub-techniques.
RESULTS
In comparison to TT, the TT resulted in 10 ± 7% lower total MR, 5 ± 4% lower aerobic MR, 30 ± 37% lower anaerobic MR, and 4.7 ± 1.2 percentage points lower GE, which resulted in a 32 ± 4% lower PO (all P < 0.01). The [Formula: see text]O and anaerobic capacity were 4 ± 4% and 30 ± 37% lower, respectively, in DP than DS (both P < 0.01). The PO for the two time-trial (TT) performances were not significantly correlated (R = 0.044). Similar parabolic pacing strategies were used during both TTs. Multivariate data analysis projected TT performance using [Formula: see text]O, anaerobic capacity, and GE (TT, R = 0.974; TT, R = 0.848). The variable influence on projection values for [Formula: see text]O, anaerobic capacity, and GE were for TT, 1.12 ± 0.60, 1.01 ± 0.72, and 0.83 ± 0.38, respectively, and TT, 1.22 ± 0.35, 0.93 ± 0.44, and 0.75 ± 0.19, respectively.
CONCLUSIONS
The results show that a cross-country skier's "metabolic profile" and performance capability are highly sub-technique specific and that 4-min TT performance is differentiated by physiological factors, such as [Formula: see text]O, anaerobic capacity, and GE.
Topics: Humans; Male; Athletic Performance; Oxygen Consumption; Skiing; Exercise Test
PubMed: 37302104
DOI: 10.1007/s00421-023-05239-8 -
International Journal of Sports... Nov 2023One hundred years ago, Hill and Lupton introduced the concept of maximal oxygen uptake (V˙O2max), which is regarded as "the principal progenitor of sports physiology."...
One hundred years ago, Hill and Lupton introduced the concept of maximal oxygen uptake (V˙O2max), which is regarded as "the principal progenitor of sports physiology." We provide a succinct overview of the evolvement of research on V˙O2max, from Hill and Lupton's initial findings to current debates on limiting factors for V˙O2max and the associated role of convective and diffusive components. Furthermore, we update the current use of V˙O2max in elite endurance sport and clinical settings. Practical Applications and Conclusions: V˙O2max is a healthy and active centenarian that remains a very important measure in elite endurance sports and additionally contributes as an important vital sign of cardiovascular function and fitness in clinical settings. Over the past 100 years, guidelines for the test protocols and exhaustion criteria, as well as the understanding of limiting factors for V˙O2max, have improved dramatically. Presently, possibilities of accurate and noninvasive determination of the convective versus diffusive components of V˙O2max by wearable sensors represent an important future application. V˙O2max is not only an indicator of cardiorespiratory function, fitness, and endurance performance but also represents an important biomarker of cardiovascular function and health to be included in routine assessment in clinical practice.
Topics: Humans; Aged, 80 and over; Exercise Test; Oxygen Consumption; Physical Endurance; Exercise; Sports
PubMed: 37770066
DOI: 10.1123/ijspp.2023-0229 -
Journal of the American Heart... Jul 2023Background An elevated ventilatory efficiency slope during exercise (minute ventilation/volume of expired CO; V/VCO slope) is a strong prognostic indicator in heart...
Background An elevated ventilatory efficiency slope during exercise (minute ventilation/volume of expired CO; V/VCO slope) is a strong prognostic indicator in heart failure. It is elevated in people with heart failure with preserved ejection, many of whom have hypertension. However, whether the V/VCO slope is also elevated in people with primary hypertension versus normotensive individuals is unknown. We hypothesize that there is a spectrum of ventilatory inefficiency in cardiovascular disease, reflecting an increasingly abnormal physiological response to exercise. The aim of this study was to evaluate the V/VCO slope in patients with hypertension compared with age-, peak oxygen consumption-, and sex-matched healthy subjects. Methods and Results Ramped cardiovascular pulmonary exercise tests to peak oxygen consumption were completed on a bike ergometer in 55 patients with primary hypertension and 24 normotensive controls. The V/VCO slope was assessed from the onset of exercise to peak oxygen consumption. Data were compared using unpaired Student test. Age (mean±SD, 66±6 versus 64±6 years; =0.18), body mass index (25.4±3.5 versus 24±2.4 kg/m; =0.13), and peak oxygen consumption (23.2±6.6 versus 24±7.3 mL/min per kg; =0.64) were similar between groups. The V/VCO slope was elevated in the hypertensive group versus controls (31.8±4.5 versus 28.4±3.4; =0.002). Only 27% of the hypertensive group were classified as having a normal V/VCO slope (20-30) versus 71% in the control group. Conclusions Ventilatory efficiency is impaired people with hypertension without a diagnosis of heart failure versus normotensive individuals. Future research needs to establish whether those patients with hypertension with elevated V/VCO slopes are at risk of developing future heart failure.
Topics: Humans; Middle Aged; Aged; Oxygen Consumption; Lung; Prognosis; Exercise Test; Heart Failure; Hypertension; Essential Hypertension; Exercise Tolerance
PubMed: 37345800
DOI: 10.1161/JAHA.121.024335