Changes In Oxygen Consumption Research Articles

Factors contributing to the change in thermoneutral maximal oxygen consumption after iso-intensity heat acclimation programmes

ABSTRACT The factors explaining variance in thermoneutral maximal oxygen uptake (O2max) adaptation to heat acclimation (HA) were evaluated, with consideration of HA programme parameters, biophysical variables and thermo-physiological responses. Seventy-one participants consented to perform iso-intensity training (range: 45%−55% O2max) in the heat (range: 30°C-38°C; 20%−60% relative humidity) on consecutive days (range: 5-days-14-days) for between 50-min and-90 min. The participants were evaluated for their thermoneutral O2max change pre-to-post HA. Participants’ whole-body sweat rate, heart rate, core temperature, perceived exertion and thermal sensation and plasma volume were measured, and changes in these responses across the programme determined. Partial least squares regression was used to explain variance in the change in O2max across the programme using 24 variables. Sixty-three percent of the participants increased O2max more than the test error, with a mean ± SD improvement of 2.6 ± 7.9%. A two-component model minimised the root mean squared error and explained the greatest variance (R2; 65%) in O2max change. Eight variables positively contributed (P < 0.05) to the model: exercise intensity (%O2max), ambient temperature, HA training days, total exposure time, baseline body mass, thermal sensation, whole-body mass losses and the number of days between the final day of HA and the post-testing day. Within the ranges evaluated, iso-intensity HA improved O2max 63% of the time, with intensity – and volume-based parameters, alongside sufficient delays in post-testing being important considerations for O2max maximisation. Monitoring of thermal sensation and body mass losses during the programme offers an accessible way to gauge the degree of potential adaptation.

Effect of a home-based inspiratory muscle training programme on functional capacity in postdischarged patients with long COVID: the InsCOVID trial

BackgroundFatigue and exercise intolerance are the most common symptoms in patients with long COVID.AimsThis study aimed to evaluate whether a home-based inspiratory muscle training (IMT) programme improves maximal functional capacity...

Sex differences in cardiovascular risk factor responses to resistance and endurance training in younger subjects.

This study compared differences in cardiovascular (CV) risk factor responses between males and females following endurance (END) and resistance (RES) training. We present the frequency of responders to each training modality and the magnitude of response. Using a randomized crossover design, 68 healthy adults [age: female (F): 24.5 ± 4.6; male (M): 27.3 ± 6.6] completed 3 mo of RES and END, with 3 mo washout. Peak oxygen consumption (V̇o2peak), strength, body composition, blood pressure, glucose, insulin, and lipids were measured. V̇o2peak (L/min) significantly increased in both sexes following END, but not RES. The magnitude of change was larger in males (F: +0.20 L/min; M: +0.32 L/min), although this did not achieve statistical significance (P = 0.051). Strength significantly increased in both sexes following RES (P < 0.01), with a larger increase in males (Leg press: F: +39 kg; M: +63 kg; P < 0.05). Lean mass significantly increased in both sexes (P < 0.01) following RES and fat mass decreased in females following END (P = 0.019). The change in C-reactive protein following END was significantly different between sexes (F: -0.4 mg/L; M: +0.5 mg/L; P = 0.035). There were no differences between sexes in the proportion of individuals who responded positively to any variable following RES or END; differences between sexes were due to the magnitude of change. Males had a larger increase in V̇o2peak following END and strength following RES. There were no sex differences in other CV risk factors. This suggests differences in physiological responses to strength and V̇o2peak may not translate to changes in CV risk in healthy subjects.NEW & NOTEWORTHY This study investigated sex differences in cardiovascular risk factors in response to different exercise training modalities. Males had a larger improvement in peak oxygen consumption following endurance training and strength following resistance training compared with females. These changes in peak oxygen consumption and strength did not translate to changes in other cardiovascular risk factors. Despite the greater magnitude of change in males, there were no sex differences in the proportion of individuals who responded to training.

Abstract 12116: Effects of Interleukin-1 Blockade With Anakinra on Peak Oxygen Consumption in Patients With Heart Failure an Analysis of On-Treatment and Off-Treatment Assessments

Introduction: Interleukin-1 (IL-1) blockade may improve exercise capacity in the subset of heart failure (HF) patient with high inflammation. Accordingly, modulating systemic inflammation with IL-1 inhibition could result in physiologic adaptations that have a beneficial effect on exercise capacity in this population. Hypothesis: Primary objective of the study was to determine changes in peak oxygen consumption (VO2) on-treatment with anakinra, an IL-1 blocker, and after treatment cessation. Methods: Cardiopulmonary exercise testing (CPET) was performed in 52 patients with HF at baseline, during daily treatment and after suspension of treatment with 100 mg anakinra. High-sensitivity C-reactive protein (CRP) was measured at the time of each CPET. Data are presented as median and interquartile range or number and percentage. Results: The cohort included twenty-six (50%) females, 36 (69%) self-identified as Black/African-American, 55 [52-62] years. Left ventricular ejection fraction (LVEF) was 43% [34-60%], CRP was 7.1 [3.7-15.8] mg/L and peak VO2 was 14.5 [12.6-17.4] ml•kg-1•min-1. Treatment duration was 4 [2-12] weeks, while time between treatment discontinuation and off-treatment CPET was 12 [6-12] weeks. Treatment with anakinra significantly reduced CRP (7.1 [3.7-15.8] to 1.5 [1.0-3.8] mg/L, p&lt;0.001) and improved peak VO2 (14.5 [12.6-17.4] ml•kg-1•min-1to 16.0 [14.0-18.6] ml•kg-1•min-1, p=0.011-Figures A and B, respectively). CRP significantly increased to 3.8 [1.4-10.7] mg/L, p=0.007, and peak VO2 significantly decreased to 15.5 [12-17.8] ml•kg-1•min-1 (p= 0.004) after anakinra suspension. Conclusions: IL-1 blockade with anakinra is associated with a reduction in systemic inflammation (CRP levels) and in an improvement in exercise capacity (i.e., peak VO2) among patients with HF during treatment. These data validate IL-1 blockade as a mediator of exercise capacity in HF; however long-term effects require further investigation.

Associations between training characteristics and change in peak oxygen consumption following exercise training in patients with heart failure with preserved ejection fraction

Abstract Introduction In heart failure with preserved ejection fraction (HFpEF), moderate continuous training (MCT) and high-intensity interval training (HIIT) are both effective in increasing peak oxygen uptake (peak V̇O2). Purpose The aim of this study was to investigate the association of training characteristics (i.e. average sessions/week, average duration/week, mean intensity) and change in peak V̇O2 following 3 months of MCT and HIIT in patients with HFpEF. Methods Among 120 patients who were randomized to MCT (5x40 min/week at 35–50% heart rate reserve [HRR]) or HIIT (3x38 min/week at 80–90% HRR), those who completed 3-month follow-up (N=107) were considered for this analysis. Training duration and heart rates [HR] were recorded with a smartphone application, evaluated with a customized software and manually checked for plausibility. If HR measurements were classified as invalid/unreliable (e.g. very strong fluctuations), patients were excluded from analysis. Intensities were calculated as average % HRR of total sessions in MCT and the average of the highest % HRR values of all intervals in HIIT. Associations between training characteristics and change in peak V̇O2 were evaluated using univariate and multivariate regression analyses. Individual HR-V̇O2 relationships were used to calculate and compare energy expenditure (MET-minutes) in MCT and HIIT. Results After excluding 16 patients due to invalid/unreliable HR data, 91 patients (67% female, 69±7 years) were included in this analysis. On average, MCT patients (N=45) performed 4.0±1.2 sessions/week (162±52 min/week) at 47.4±6.7% HRR, while HIIT patients (N=46) performed 2.4±0.8 sessions/week (96±40 min/week) at 81.8±11.8% HRR. Peak V̇O2 was improved by 1.70±2.35 ml/kg/min in MCT and 1.46±2.98 ml/kg/min in HIIT (difference: 0.24 [95% CI, −0.87 to 1.34], p=0.67). The associations between training characteristics and change in peak V̇O2 are shown in Fig.1. Mean % HRR was not significantly associated with the change in peak V̇O2 in the HIIT group, whereas in MCT, mean duration/week and mean intensity were of similar relative importance (standardized coefficients) and explained up to 26% of the variation in change in peak V̇O2 (Table 1). Average weekly MET-minutes above rest were 451±260 for MCT and 389±375 for HIIT (difference: 62 [95% CI, −71 to 195], p=0.36). After adjustment for MET-minutes, the difference in change in peak V̇O2 between groups diminished to 0.09 ml/kg/min (95% CI, −0.97 to 1.16; p=0.98). Conclusions Weekly duration and mean % HRR had a similar predictive ability for the change in peak V̇O2 following MCT with, interestingly, lower change in peak V̇O2 with increasing intensity. In HIIT, mean % HRR was not significantly associated with the change in peak V̇O2. After adjusting for energy expenditure, the difference in change in peak V̇O2 between training modes diminished, suggesting that MCT and HIIT were similarly effective. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Commission, Framework Program 7

SPORTS BRA SUPPORT ALTERS METABOLIC COST AND ECONOMY PROFILES DURING TREADMILL RUNNING

1,2Alexis K. Nelson, 2Jay J. Hinton, 2Hailey B. Fong, 2Julie E. Woolfolk, 1,2Douglas W. Powell FACSM1University of Tennessee Health Science Center, 2University of Memphis Sponsor: Douglas W. Powell, FACSM The breast is a passive tissue that has been described as a wobbling mass on a rigid torso. With limited intrinsic support, female athletes are required to provide extrinsic breast support from a sports bra. Little is known about the influence of sports bra support on the bioenergetics of running. Only a single study with a small sample size has investigated sports bra support-related changes in oxygen consumption during a running task. PURPOSE: To quantify the effect of sports bra support on metabolic cost of running and running economy. METHODS: 14 female recreational runners performed a 10-minute treadmill running task at their preferred speed in each of 2 randomized sports bra support conditions: low support (LOW) and high support (HIGH), where the conditions were characterized by the athlete wearing a low or high supports bra, respectively. Indirect calorimetry was recorded for each 10-minute trial using a metabolic measurement system (Parvo Medics, Sandy, UT). Metabolic cost was calculated as the average VO2 measured across the duration of the trial while running economy was calculated as the quotient of the running distance divided by the sum of the VO2 across each 10-minute trial. A paired samples t-test was used to compare mean oxygen consumption and running economy values in the LOW and HIGH conditions. RESULTS: HIGH was associated with lower metabolic cost (L/min, p = 0.004) and improved running economy (m/L O2, p = 0.004) compared to LOW. CONCLUSIONS: Sports bra support alters the metabolic cost and economy of running. Underlying mechanisms may be related to increased pelvic and trunk rotation allowing runners to take longer strides without the burden of high breast accelerations.

Four Weeks Of A Ketogenic Diet Increases Oxygen Consumption And Fat Oxidation During Moderate-intensity Walking

PURPOSE: Establish the time-course of changes in oxygen consumption, substrate metabolism, and heart rate during treadmill walking upon commencing a ketogenic diet. METHODS: In a randomized, parallel design, 53 men and women (mean ± SD, age: 35 ± 16 years, body mass index: 24 ± 3 kg/m2) were allocated to a moderate-sugar, moderate-carbohydrate diet [MODSUG; contribution of carbohydrate (of which sugars), fat and protein to total energy intake: 50% (15%), 35%, and 15%, respectively] a low-sugar, moderate-carbohydrate diet [LOWSUG; 50% (5%), 35%, and 15%, respectively] or a low-carbohydrate, ketogenic diet [LOWCHO; 8% (2%), 77%, and 15%, respectively] for 12 weeks. Oxygen consumption and substrate metabolism were determined by Douglas bags and heart rate using electrocardiography during submaximal walking at baseline, 4-weeks and 12-weeks of the dietary intervention. The submaximal treadmill test comprised 5-minute stages at 5.2 km/h with gradients of 0%, 3%, 6% and 9%. Data were analyzed by two-way (group x time) ANOVA with post-hoc test corrected for multiple comparisons by the Bonferroni method. RESULTS: Mean oxygen consumption rates displayed a group x time interaction (P = 0.016) whereby LOWCHO increased oxygen consumption from 17.8 ± 1.8 mL/kg/min at baseline to 18.4 ± 2.1 mL/kg/min by week 4 (P = 0.02), after which levels remained elevated at 18.4 ± 2.2 at week 12 (P > 0.05). Mean heart rate during all gradients increased with LOWCHO from 115 ± 12 beats/min at baseline to 121 ± 12 beats/min by week 4 (group x time interaction, P = 0.026; post-hoc comparison, P = 0.04), reaching 120 ± 14 beats/min at week 12 (P > 0.05). Peak fat oxidation rates increased with LOWCHO from 0.37 ± 0.18 g/min at baseline to 0.58 ± 0.25 g/min at week 4 with concomitant decreases in carbohydrate oxidation rates (group x time interaction, P < 0.001; post-hoc comparison, P < 0.001) with no further increases at week 12 (0.56 ± 0.27 g/min; P > 0.05). No such increases were observed with MODSUG or LOWSUG (all P > 0.05). CONCLUSIONS: Adaptations of oxygen consumption, heart rate and fat oxidation during walking plateau by 4 weeks of commencing a low-carbohydrate ketogenic diet, suggesting 4 weeks is sufficient to maximise metabolic adaptations to exercise with ketogenic diets. Supported by The Rank Prize Funds and Kenniscentrum Suiker & Voeding.

Exercise Dose and Aerobic Fitness Response in Alzheimer's Dementia: Findings from the FIT-AD Trial.

The purpose of this study was to examine the effects of a 6-month cycling aerobic exercise intervention on cardiorespiratory fitness and the dose-response relationship in community-dwelling older adults with mild-to-moderate Alzheimer's dementia. The FIT-AD trial was a single blind, 2-parallel group, pilot randomized controlled trial. The aerobic exercise group participated in a 6-month, thrice weekly, moderate-vigorous intensity cycling intervention while control group performed stretching. Cardiorespiratory fitness was evaluated by peak oxygen consumption from cardiopulmonary exercise test and peak walking distance from the shuttle walk test and 6-minute walk test. Aerobic exercise dose was calculated using the novel heart rate physical activity score. The aerobic exercise group significantly increased peak oxygen consumption (1.28 ml/kg/min; p=0.03) in subgroup who achieved maximal criteria on cardiopulmonary exercise test. Changes in peak oxygen consumption and peak walking distance on the shuttle walk and 6-minute walk tests did not significantly differ between aerobic exercise and stretching groups. Notably, the aerobic exercise dose was strongly and significantly correlated to change in peak oxygen consumption (r=0.60; n=16; p=0.01), in subset who met maximal test criteria. Emphasis on exercise dose is needed in aerobic exercise programs to maximize cardiorespiratory fitness gains in persons with mild-moderate Alzheimer's dementia.

Metabolic adaptation after combined resistance and aerobic exercise training in older women.

This study investigated whether combined aerobic and resistance training in older women leads to metabolic adaptation. A total of 80 women (64 White individuals; BMI: 30.0[4.4]kg/m2 ; age: 64.8[3.5]years) followed 32 weeks of aerobic and resistance training. Body weight/composition (dual-energy X-ray absorptiometry) and resting metabolic rate (RMR; indirect calorimetry) were measured at baseline, week 16, and week 32. Metabolic adaptation was defined as significantly lower measured versus predicted RMR. A regression model to predict metabolic adaptation was developed that included race, age, baseline fat-free mass, RMR and respiratory quotient, and changes in net submaximal oxygen consumption after different tasks. There was significant metabolic adaptation at week 16 (-59[136]kcal/d, p=0.002), following a 640-kcal/wk energy loss (-0.7[2.6]kg of weight loss). In 53 women with complete data, metabolic adaptation was seen both at week 16 (-64[129]kcal/d, p=0.001) and at week 32 (-94[127]kcal/d, p < 0.001). Metabolic adaptation at week 16 was predicted by race, age, baseline fat-free mass, RMR and respiratory quotient, and change in net oxygen consumption of walking (R2 adjusted=0.90, p < 0.001). Similar results were seen at week 32. In older women with overweight and obesity, a minimal energy deficit induced by aerobic and resistance exercise is associated with metabolic adaptation at the level of RMR.

Three Physiological Components That Influence Regional Cerebral Tissue Oxygen Saturation.

Near-infrared spectroscopy (NIRS) measurement of regional cerebral tissue oxygen saturation (rcStO2) has become a topic of high interest in neonatology. Multiple studies have demonstrated that rcStO2 measurements are feasible in the delivery room during immediate transition and resuscitation as well as after admission to the neonatal intensive care unit. Reference ranges for different gestational ages, modes of delivery, and devices have already been published. RcStO2 reflects a mixed tissue saturation, composed of arterial (A), venous (V), and capillary signals, derived from small vessels within the measurement compartment. The A:V signal ratio fluctuates based on changes in oxygen delivery and oxygen consumption, which enables a reliable trend monitoring of the balance between these two parameters. While the increasing research evidence supports its use, the interpretation of the absolute values of and trends in rcStO2 is still challenging, which halts its routine use in the delivery room and at the bedside. To visualize the influencing factors and improve the understanding of rcStO2 values, we have created a flowchart, which focuses on the three major physiological components that affect rcStO2: oxygen content, circulation, and oxygen extraction. Each of these has its defining parameters, which are discussed in detail in each section.

Effects of the addition of high- vs. low-intensity resistance training on top of endurance training in patients with heart failure: preliminary results from a randomized clinical trial

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Hasselt University Background Adding resistance training on top of endurance training is recommended in the rehabilitation of patients with heart failure. However, it is unknown which intensity of resistance training should be preferred. Purpose To compare the effects of the addition of high- vs. low-intensity resistance training on top of endurance training in patients with heart failure. Methods Nineteen patients with heart failure were block randomized (by gender and sex) in a combined high-intensity resistance and endurance group (HIG; n=8, age=61±12y, 7 males, LVEF=38±10%) vs. combined low-intensity resistance and endurance group (LIG; n=9, age=68±21y, 8 males, LVEF=38±13%). Patients trained 3x/week for 45 sessions. The resistance exercises were volume-matched between groups and consisted of three sets of leg press, pull down and dip exercises, separated by 30s of rest, done at 55-70% 1RM in HIG vs. 35-40% 1RM in LIG. Both groups did moderate-intense endurance training on a bicycle, cross-trainer, treadmill and arm ergometer for 30 min per training. Maximal oxygen consumption was evaluated with an incremental cardiopulmonary cycling test and muscle strength by 1-RM testing, while quality of life was assessed with the Minnesota questionnaire, and walking distance by a 6-minute walking test. Mann-Whitney U test was used for analyzing differences between groups in all variables and Wilcoxon signed-rank test for evaluating pre-post difference of the entire sample. P values &amp;lt;0,05 (2-tailed) were considered statistically significant. Results Training adherence was similar in both groups (LIG vs HIG: 41±6 vs 37±9 sessions, p=0,370; Table 1). Overall, the intervention improved maximal oxygen consumption, walking capacity and muscle strength (p&amp;lt;0,05), but the between-group changes in maximal oxygen consumption (LIG vs HIG: 3±2 vs 3±4 ml/kg/min, p=0,963), quality of life (LIG vs HIG: -8±23 vs -1±5 points, p=0,931) and muscle strength (LIG vs HIG: Dip 34±34 vs 18±20kg, p=0,481; Leg press, 66±87 vs 47±53kg, p=0,486; Pull down, 9±6 vs 9±7kg, p=0,574) were similar. Conclusion Adding either high- or low-intensity resistance training on top of endurance training seems equally effective for improving aerobic capacity and walking performance in patients with heart failure. The study is ongoing.

Metabolic Effects of Sodium Fluorocitrate and Potential Treatments on Saccharomyces Cerevisiae: Changes in Oxygen Consumption

Sodium fluoroacetate (1080) is a colorless, odorless, tasteless, water‐soluble metabolic poison. In the body, fluoroacetate is converted to fluorocitrate (FC) which blocks the citric acid cycle and drastically decreases ATP production. Symptoms of exposure include nausea, vomiting, abdominal pains, salivation, irrational fear, weakness, tachypnea, cyanosis, sweating, increased temperature, and death. Signs and symptoms of 1080 poisoning are nonspecific, further complicating the diagnosis. 1080 is tightly regulated within the United States, but it is commonly used in Australia, New Zealand, Mexico, Japan, South Korea, and Israel as a rodenticide to control invasive and predatory species. An eco‐terrorist scare in New Zealand (2015) and findings reported by the CIA (2007) have led 1080 to being identified as a potential terrorist weapon.To identify potential countermeasures against 1080 poisoning, a Saccharomyces cerevisiae (yeast) model was selected to assess the impact of FC on cellular respiration and to screen candidate therapeutics. In response to FC, yeast showed depressed mitochondrial activity as measured by oxygen consumption rate (OCR). Potential treatments, thonzonium bromide, nifuroxazide, pyrvinium pamoate, menadione, mefloquine, clemastine fumarate, bisacodyl, L‐ascorbic acid, thiethylperazine and vinpocitine, were examined in this study. All treatments are approved by the Food and Drug Administration. Toxicity of each treatment was also assessed.Assays were performed in yeast extract peptone galactose media, a metabolically restrictive media. To assess the effect of FC on OCR, cells were exposed to 50 µM, 100 µM, and 200 µM FC in liquid culture for 1, 4, or 24 hours. After incubation, mitochondrial respiration was assessed via the MitoXpress assay (Agilent), a fluorescence‐based assay that measures OCR. Once established as a viable model, yeasts were then used to screen therapeutics to improve cellular respiration. Yeast was co‐incubated with fluorocitrate (200 µM), and potential treatments at three increasing concentrations for 4 hours and the effects on mitochondrial respiration were assessed via the MitoXpress assay.Following the decreased OCR in yeast exposed to FC, 6 of the 10 treatments successfully restored the mitochondrial function of yeast as demonstrated by an increase in OCR. As a result, the compounds nifuroxazide, pyrvinium pamoate, vinpocitine, clemastine fumarate, bisacodyl, and L‐ascorbic acid are moving forward for further testing in cardiomyocytes and hepatic spheroids, with potential in vivo assessment, to characterize their effectiveness against 1080 poisoning. Future studies will continue to use yeast as a valuable screening method to identify other potential treatments for sodium fluoroacetate.

Inhibition of Forebrain Microglia Ameliorates Non‐alcoholic Fatty Liver Disease During Obesity

Non‐alcoholic fatty liver disease (NAFLD), characterized by increased hepatic triglycerides (i.e. steatosis), leads to an increased risk for type II diabetes, cardiovascular disease and obesity‐related mortality. Accumulating data points to central nervous system (CNS) alterations as a NAFLD contributor. In this context, we have recently shown that pharmacological inhibition of microglia, the resident immune cells of the brain, attenuates NAFLD during obesity. However, the brain regions involved in this microglial driven steatosis remains unknown. The forebrain subfornical organ (SFO), a circumventricular nucleus situated outside of the blood‐brain‐barrier, has recently been suggested to be critical in NAFLD. Based on this, we hypothesized that SFO microglia activation contributes to hepatic steatosis during obesity. To investigate this, we used a common murine model of diet‐induced NAFLD where male C57Bl/6J mice were fed a high fat diet (HFD, 60% kCal fat) or normal chow for 11 weeks, starting at 6 weeks of age. Immunohistochemistry for ionized calcium‐binding adapter molecule 1 (Iba1) revealed SFO microglia activation following HFD feeding (1.0±0.01 vs 1.4±0.15, relative Iba1 intensity, normal chow vs HFD, p&lt;0.05, n=7). 3‐dimensional analysis further indicated that HFD feeding was associated with a shift to an activated SFO microglia morphology, including decreased branching complexity and shorter dendrites (e.g. branch #/dendrite: 3.1±0.2 vs 2.5±0.1, normal chow vs HFD, p&lt;0.05, n=5/group, 203‐364 microglia/animal). Building upon this, we employed a chemogenetic strategy to selectively inhibit SFO microglia. HFD or normal chow male mice underwent SFO stereotaxic delivery of a designer receptors exclusively activated by designer drugs inhibitory construct targeted to microglia via the CD68 promoter (pAAV‐CD68‐hM4Gi‐mCherry). Following surgical recovery, the pharmacological ligand clozapine‐N‐oxide (CNO; 3 mg/kg i.p.) was administered once daily over 3 days to inhibit SFO microglia. Saline served as a control (n=7–11/group). Short‐term inhibition of SFO microglia did not alter body weight (43±1 vs 42±2 g, HFD saline vs CNO, p&gt;0.05) and food intake in normal chow or HFD fed mice. Similarly, indirect calorimetry evaluations revealed no change in oxygen consumption, respiratory exchange ratio, or energy expenditure in either diet group during SFO microglia inhibition (e.g. energy expenditure: 0.49±0.01 vs 0.49±0.01 kcal/hr, HFD saline vs CNO, p&gt;0.05). Regional adiposity including visceral, subcutaneous, and brown adipose mass was also not different between CNO and saline treated animals. However, histological examination (Oil Red O staining) revealed widespread hepatic lipid accumulation in HFD fed mice (0.4±0.1 vs 36.2±5.5 %stained area; normal chow saline vs HFD saline, p&lt;0.05), which was reduced by ~49% following 3‐day SFO microglia inhibition (18.4±5.4 %stained area, HFD CNO, p&lt;0.05 vs HFD saline). This decline in hepatic steatosis in response to SFO microglia inhibition was further confirmed with liver triglyceride measurements. In line with the direct association of NAFLD and type II diabetes, inhibition of SFO microglia also resulted in a reduction in fed blood glucose levels in obese mice (229±24 vs 182±9 mg/dl, HFD saline vs CNO, p=0.05). Collectively, these results indicate that SFO microglia activation is a critical contributor to hepatic steatosis during obesity.

Changes in Oxygen Consumption and Metabolomic Profiles in the Kidney of Sprague‐Dawley Rat fed a High‐Salt Diet

The metabolism of oxygen and substrates in the kidney under normal conditions and in salt‐sensitive hypertension is still not well understood. A novel method was developed to collect renal arteriovenous blood and urine from conscious freely moving rats, while measuring renal blood flow (RBF) and blood pressure (BP). As such, global renal O2 consumption and metabolic profiles can be studied in response to various stimuli such as changes in salt diet. We report here changes observed in male Sprague‐Dawley rats (SD; 10 wk age) before and after 21 days switching from a 0.4% NaCl (LS) diet to a 4.0% NaCl diet (HS). Rats were surgically instrumented with a renal ultrasonic artery flow probe (Transonic), a femoral arterial catheter, and a renal venous catheter and placed in a movement response caging system. After 7 days recovery, control levels of RBF and BP (24 hr/day) were obtained, and arterial and renal venous blood were sampled. Rats were then switched to the HS diet and blood sampled at days 7, 14 and 21 while RBF and BP were recorded continuously throughout the study. Blood O2 content was measured by radiometer immediately after blood collection and plasma samples frozen for global metabolomic analysis by the Jackson laboratory. The metabolomic analysis (Thermo Q‐Exactive Orbitrap coupled to a Vanquich UPLC system) was performed in 4 modes (C18 positive, C18 negative, HILIC positive and HILIC negative). Average 24 hr mean arterial pressure (MAP) of the SD rats increased slightly over the 21 days of the HS diet from 111 ± 2 to 119 ± 5 mmHg (p&lt;0.05; n=7). Average 24 hr RBF rose from 9.2 ± 0.6 to 11.7 + 0.6 ml/min (p&lt;0.05). O2 consumption increased significantly from 0.17 ± 0.03 to 0.26 ± 0.03 ml/min (p&lt;0.05) as did O2 extraction which increased from 10.8 ± 1.1 % to 15.0 ± 1.2 % by Day 21 of HS diet. Of a total 1205 named metabolites detected, we present here those that differed between arterial and renal venous blood by more than 2‐fold and significantly (p&lt;0.05; Benjamini‐Hochberg corrected). At the time of this report, in rats fed the LS diet, 33 compounds were found more abundant in arterial blood than in venous blood. 10 compounds were found more abundant in venous blood. The HS diet increased the arterial / venous ratio of some compounds progressively throughout the 21 days while others decreased. No evidence of anaerobic respiration was obtained with lactate, pyruvate, glutamate and TCA cycle related metabolites remaining unchanged throughout the study. Interestingly, some gut microbiome generated compounds were found to differentially altered by the HS diet. Despite no changes in arterial concentrations, a progressive reduction was observed in Triethylamine in the renal venous blood at each time point, while a progressive elevation was observed in Hexanoic acid. Venous levels of Cis‐4‐Decenedioic acid and Succinylacetone, known to be altered in some metabolic diseases were significantly increased by the HS diet. Urine measurements and cortical and outer medullary tissue measurements are currently under way which together with the RBF will enable calculation of metabolic fluxes of these various metabolites. We conclude that a high‐salt diet increases oxygen consumption and alters the metabolomic profiles of the kidney.

The effect of copper and cadmium on oxygen consumption of the juvenile common carp, Cyprinus carpio (L.)

This study was carried out on juvenile Cyprinus carpio (L.) to investigate the effects of sub-lethal concentrations of copper and cadmium (0.1, 0.25, 0.4 ppm) on the survival rate, oxygen consumption and histopathological changes in the gills of exposed fish. The results showed a decrease in survival rate with increasing concentration of each metal. Copper has the most toxic effect compared with cadmium, the survival rate has decreased from 50% to 10% for copper and from 70% to 20% for cadmium with increasing concentration for 15 days. The half lethal time (LT50) was (14 and &gt;15) days for copper and cadmium, respectively. Oxygen consumption rate decreased with increasing concentration and there was a negative correlation between oxygen consumption and metal concentration. The exposure to each metal caused histopathological changes in the gill and resulted in separation of epithelial secondary gill lamellae, hyperplasia, fusion of secondary lamellae and necrosis.

Effects of different brisk walking intensities on adherence and cardiorespiratory endurance of cardiac rehabilitation among patients with CHD after PCI: protocol for a randomised controlled trial

IntroductionCardiac rehabilitation (CR) is a critical treatment for patients with coronary heart disease after percutaneous coronary intervention. Unfortunately, participation and adherence of CR are unexpectedly poor. This study aims to...

엘리트 태권도 선수의 경기 중 심박수, 혈중 젖산, 혈압, 심근산소소비량의 변화

In this study, by observing the changes in heart rate, blood lactate, blood pressure, and myocardial oxygen consumption during the entire competition, male and female Taekwondo elite athletes performed 3 rounds of 3 minutes for men and 3 times for 2 minutes for women, respectively, the exact exercise intensity of Taekwondo was evaluated. The purpose is to provide basic data for understanding and to present the theoretical basis for planning scientific training. The subjects of this study consisted of 16 university players, 8 male and 8 female. Heart rate, blood pressure, and blood lactate were measured, and myocardial oxygen consumption was calculated from the measured systolic blood pressure and heart rate. Measurement time is at rest, end of round 1, rest 1(1 min), end of round 2, rest 2 (1 min), end of round 3, rest 3 (1 min), recovery period (3 min) after game 8 times classified as.<BR>As a result of this 1. There was no significant difference between the sexes in the change of heart rate in the Taekwondo competition, and there was a significant difference between the 1st/2nd and 1st/3rd rounds during the R competition, which corresponds to 90-95% of the maximum heart rate. 2. There was no significant difference between the sexes in the change of blood lactate, and there was a significant difference at the end of each rotation, which corresponds to an approximately 3-fold increase at the end of the 3rd rotation compared to the rest. 3. As for the change in blood pressure, there was no significant difference in systolic blood pressure between the sexes, and there was a significant difference in diastolic blood pressure. Male athletes were higher than female athletes by time. 4. The change in myocardial oxygen consumption showed a significant difference between the sexes, and it was found to be about 2-3 times higher than at rest.

Effect of γ-oryzanol on oxygen consumption and fatty acids changes of canola oil

γ-oryzanol has been well studied for its hypolipidemic, antidiabetic, antiallergic, and anti-inflammatory abilities. However, its ability against lipid oxidation has not been thoroughly explored. The present study examined the effects of γ-oryzanol against canola oil oxidation under Chinese cooking temperatures compared with that of butylated hydroxytoluene (BHT). Changes of oxygen consumption and fatty acids of canola oil with addition of 2–8 mg/g γ-oryzanol were conducted under 60, 90, 120, and 180 °C, respectively. Results showed although γ-oryzanol was not as effective as BHT against lipid oxidation of heated canola oil, it showed an inhibitory effect on the headspace oxygen consumption dose-dependently. Besides, γ-oryzanol significantly prevented the decrease of total polyunsaturated fatty acids in canola oil heated at 60–120 °C, while such effect was not observed in canola oil heated at 180 °C. β-sitosteryl ferulate, one of the major components constituting γ-oryzanol, degraded faster than cycloartenyl ferulate, 24-methylene cycloartanyl ferulate, and campesteryl ferulate at all treatment conditions. In conclusion, γ-oryzanol might have a potential application against lipid oxidation in foods as a functional antioxidant.

Functional improvement following direct interventional leaflet repair of severe tricuspid regurgitation.

AimsSeveral new percutaneous tricuspid repair systems have recently been introduced as new treatment options for severe tricuspid regurgitation (TR). Clinical improvement following percutaneous tricuspid valve leaflet repair has been demonstrated by recent studies. A possible impact on exercise capacity has not yet been reported.Methods and resultsEleven patients with at least severe TR and successful tricuspid leaflet repair using the PASCAL Ace implant at our cardiology department were included in this analysis. All patients suffered from symptomatic right‐sided heart failure with compromised exercise capacity. Cardiopulmonary exercise testing (CPET), clinical, laboratory, and echocardiographic parameters were assessed at baseline and 3 months follow‐up. The primary endpoint was the change in maximal oxygen consumption [VO2 max (mL/(min*kg))] at 3 months follow‐up. Secondary endpoints included improvement in TR, cardiac biomarkers, and other clinical outcomes. TR severity at 3 months follow‐up post‐PASCAL Ace implantation was significantly lower than at baseline (P = 0.004). Cardiac biomarkers including high‐sensitivity troponin T and N‐terminal pro‐brain natriuretic peptide as well as right ventricular diameter improved slightly without reaching statistical significance (P = 0.89, P = 0.32, and P = 0.06, respectively). PASCAL Ace implantation resulted in a significant improvement in cardiopulmonary exercise capacity at 3 months follow‐up compared with baseline. Mean VO2 max improved from 9.5 ± 2.8 to 11.4 ± 3.4 mL/(min*kg) (P = 0.006), VO2 max per cent predicted from 42 ± 12% to 50 ± 15% (P = 0.004), peak oxygen uptake from 703 ± 175 to 826 ± 198 mL/min (P = 0.004), and O2 pulse per cent predicted from 67 ± 21% to 81 ± 25% (P = 0.011). Other CPET‐related outcomes did not show any significant change over time.ConclusionsIn this single‐centre retrospective analysis, direct tricuspid valve leaflet repair using the transcatheter PASCAL Ace implant system was associated with a reduced TR severity and improved cardiopulmonary exercise capacity.

The Effect of a Single Dose of Thiamine on Oxygen Consumption in Patients Requiring Mechanical Ventilation for Acute Illness: A Phase II, Randomized, Double-Blind, Placebo-Controlled Trial.

IMPORTANCE:Lower oxygen consumption is associated with worse survival in septic shock and in other forms of critical illness. No treatment that increases oxygen extraction, a key determinant of oxygen consumption, has been found. Thiamine is required for aerobic metabolism, and deficiency is common in the critically ill.OBJECTIVES:We evaluated the effect of thiamine on oxygen consumption in patients requiring mechanical ventilation for an acute illness.DESIGN:Phase II, randomized, double-blind, and placebo-controlled trial.SETTING AND PARTICIPANTS:ICUs in a tertiary care hospital in the United States. Patients admitted to the ICU and requiring mechanical ventilation were screened for enrollment.INTERVENTIONS:After enrollment, baseline measurement of oxygen consumption and baseline laboratories including lactate, central venous oxygen saturation, and pyruvate dehydrogenase, a single dose of 200 mg IV thiamine or placebo was administered. Oxygen consumption was then monitored for 6 additional hours and repeat laboratories were drawn at the end of the protocol.MAIN OUTCOMES AND MEASURES:The primary outcome was the change in oxygen consumption. Analysis was done using linear regression with a first-order autoregressive variance-covariance structure to account for repeated measures within subjects. Secondary outcomes included change in lactate, central venous oxygen saturation, and pyruvate dehydrogenase quantity and activity.RESULTS:Sixty-seven patients were enrolled. After excluding 11 patients due to inadequate quantity or quality of oxygen consumption data, 56 patients were included. There was no difference in change in oxygen consumption in the 6 hours after study drug. Results for secondary outcomes were similarly negative. In the prespecified subgroup of 18 thiamine deficient patients, there was a difference in the two oxygen consumption curves (p = 0.006), although no difference in median oxygen consumption or area under the curve.CONCLUSIONS AND RELEVANCE:A single dose of IV thiamine did not alter oxygen consumption in patients requiring mechanical ventilation for acute illness.