Oxygen Uptake Levels Research Articles

Effects of preparticipating hypohydration oncardiac burden in recreational athletes.

The global temperature rise will have extensive consequences on our organ systems, but hypohydration caused by reduced water intake or increased water loss through sweating plays the most relevant role. Many studies have already demonstrated the association between hypohydration and impaired exercise performance, but data related to the cardiac burden of hypohydration are scarce. This study is a sub-investigation of our large, prospective, self-controlled trial on the effects of hypohydration on cardiopulmonary exercise capacity with previously published results. In the current sub-study, we analyzed the impact of hypohydration on cardiac burden in this cohort of fifty healthy, recreational athletes during cardiopulmonary exercise test.Therefore, each participant underwent cardiopulmonary exercise test with a standardized ramp protocol twice, once in hypohydrated state and once in euhydrated state as control, and the cardiac markers Troponin T, NT-pro-BNP and Chromogranin A were measured before and after the exercise test at each state. Mean age was 29.7 years and 34% of probands were female. Hypohydration led to a reduced body water, a significant decrease in oxygen uptake and lower levels of power output. Yet, Troponin T, NT-proBNP, Chromogranin A and lactate levels did not significantly differ between the two conditions.In this study cohort, decreased exercise capacity during hypohydration was more likely due to impaired cardiac output with diminished plasma volume rather than measurable cardiac stress from fluid deprivation. However, whether these data are generalizable to a diseased cohort is left unanswered and should be addressed in future randomized controlled trials.

Effect of high-intensity interval training and moderate-intensity continuous training on cardiovascular risk factors in adolescents: Systematic review and meta-analysis of randomized controlled trials

BackgroundIn recent years, cardiovascular diseases in adolescents have become more serious. High intensity interval training (HIIT) and moderate intensity continuous training (MICT) have been shown to improve cardiovascular diseases in adolescents. Meta-analysis was conducted to compare the effects of HIIT and MICT on cardiovascular risk factors in adolescents. MethodsRandomised controlled trials of HIIT and MICT for cardiovascular risk factors in adolescents up to January 2023 were searched using authoritative databases such as CNKI, Web of Science, PubMed, and EBSCO. Data analysis was performed using Review Manage 5.4 and Stata 14.0. ResultsA total of 12 studies involving 468 participants, mean age 15.19±4.35, were included in the study. The findings showed that compared with MICT, HIIT reduced adolescents' body weight (SMD=-0.18, 95 %CI=-0.58, 0.21) and increased maximal oxygen uptake (SMD=0.56, 95 %CI=0.20, 0.93) and high-density lipoprotein (SMD=-0.47, 95 % CI=-1.11, 0.17), and improved systolic blood pressure (SMD=-0.35, 95 %CI=-0.78, 0.09), glucose (SMD=-1.53, 95 %CI=-2.93, -0.13), and insulin (SMD=-0.66, 95 % CI=-1.73, 0.41), p<0.05. HIIT and MICT improved BMI, fat mass, diastolic blood pressure, triglycerides, total cholesterol, and LDL, with no significant difference between these training types. ConclusionHIIT was better than MICT for improving cardiovascular health in adolescents, with better effects on body weight, BMI, fat mass, systolic blood pressure, diastolic blood pressure, maximal oxygen uptake, triglyceride, total cholesterol, LDL, HDL, glucose, and insulin levels.

Cardiorespiratory Fitness in Middle-aged Men and Women through the Queens College Step Test: A Cross-sectional Study

Introduction: Increased Body Mass Index (BMI) is associated with a decreased level of maximium oxygen uptake (VO2 max), which indirectly affects Cardiorespiratory Fitness (CRF) in young adults. Therefore, it is important to assess CRF in the middleaged population, despite a high burden of cardiovascular risk factors in this age group. CRF refers to the circulatory system’s ability to supply oxygen to functioning muscles during continuous physical exercise. Maximum oxygen uptake (VO2 max) is the best measure of CRF and serves as the gold standard for quantifying an individual’s aerobic capacity. Aim: To evaluate CRF in middle-aged men and women. Materials and Methods: The present cross-sectional study conducted in the Department of Physiotheraphy, NITTE Institute of Physiotheraphy included a total of 134 subjects aged between 45 and 65 years, who were selected from Justice KS Hegde Charitable Hospital in Mangaluru, Karnataka, India. The male and female groups consisted of 67 subjects each. The study was conducted over a period of 12 months, from March 2022 to March 2023. All subjects were included based on specific inclusion criteria. VO2 max was estimated by following the Queens College Step Test (QCST) method. The Pearson's correlation coefficient was used to examine the relationship between age, height, weight, BMI, waist-to-hip ratio, heart rate, and VO2 max. A p-value &lt;0.05 was considered statistically significant. Results: The mean value of VO2 max was assessed and compared between middle-aged males (65.8±3.5 mL/kg/min) and females (46.6±1.7 mL/kg/min). It was discovered that VO2 max was significantly higher in middle-aged males than in middle-aged females (p&lt;0.001), as indicated by heart rate changes from pretest to post-test. The mean value of BMI was compared between males (24.4±3.2) kg/m2 and females (24.4±4.9) kg/m2 , and the difference was found to be statistically non significant (p-value=0.916). Similarly, the mean value of waist-to-hip ratio was compared between males (0.9±0.1) and females (0.9±0.1), and the difference was also statistically non significant (p-value=0.637). Conclusion: Middle-aged males exhibit substantially higher VO2 max compared to middle-aged females (p&lt;0.001). Consequently, middle-aged females demonstrate a considerable decrease in aerobic capacity, as indicated by VO2 max, and decreased cardiovascular fitness, which serve as predictors of cardiovascular disease risk factors.

Effect of altitude training on the aerobic capacity of athletes: A systematic review and meta-analysis

PurposeWith a growing number of athletes and coaches adopting altitude training, the importance for rationalizing and optimizing such training has been emphasized. We conducted a meta-analysis to evaluate the influence of altitude training on athletes' aerobic capacity and to explore the best altitude training method to improve this capacity. MethodsWe searched Web of Science, SpringerLink, Science Direct, EBSCO, and PubMed databases combined with manual search of the references to collect studies indexed from 1979 to September 2020 on the effect of altitude training on athletes' aerobic capacity. Data from experimental studies that reported hemoglobin levels and maximum oxygen uptake in athletes before and after altitude training, or in athletes performing altitude training in comparison with a control group were analyzed. Data of the populations, intervention, comparison, outcomes and study design were extracted. Review Manager software 5.3 was used for bias evaluation. Results17 publications were included. In our meta-analysis, altitude training led to higher maximum oxygen uptake [standardized mean difference (SMD) = 0.67, 95% confidence interval (CI) 0.35–1.00, P < 0.001] and hemoglobin level (SMD = 0.50, 95% CI 0.11–0.90, P = 0.013) than training at lower altitude. The result of sensitivity analysis showed that results of meta-analysis were relatively stable, and there was no bias or change in the result of effect size according to the bias test. The results of subgroup analysis showed that high-altitude living and low-altitude training (“Hi-Lo” regime), with a training cycle of about three weeks at an altitude around 2500 m, had better effects than other regimes on the athletes’ aerobic capacity. ConclusionsAltitude training can improve athletes’ aerobic capacity in terms of maximum oxygen uptake and hemoglobin level. Our results are limited by the number and quality of available studies. Therefore, more high-quality studies are needed to verify and extend these findings. Our study can provide scientific suggestions for the training of athletes.

Effect of Exercise Training on Some Anti-Inflammatory Adipokines, High Sensitivity C-Reactive Protein, and Clinical Outcomes in Sedentary Adults With Metabolic Syndrome.

This study aimed to investigate the effects of aerobic interval training and resistance training on anti-inflammatory adipokines, high sensitivity C-reactive protein, and clinical outcomes in sedentary men with metabolic syndrome. A total of 33 sedentary men with metabolic syndrome (age: 46.2 ± 4.6years; body mass index: 35.4 ± 1.9kg.m2) were randomly assigned to one of 3 groups: aerobic interval training (n = 12), resistance training (n = 10), or control (n = 11). Participants in the exercise groups completed a 12-week training program, 3 sessions per week, while those in the control group maintained their sedentary lifestyle. The levels of high sensitivity C-reactive protein (hs-CRP), omentin-1, adiponectin, lipid profiles, blood pressure, glucose metabolism, body composition, and peak oxygen uptake (VO2peak) were measured at baseline and after the intervention. Both aerobic interval training and resistance training significantly improved the levels of omentin-1 and adiponectin, as well as reduced inflammation, as indicated by a decrease in hs-CRP levels. Exercise training also led to significant improvements in lipid profiles, blood pressure, glucose metabolism, and body composition. Specifically, the aerobic interval training group had significantly greater increases in high-density lipoprotein cholesterol and VO2peak, as well as greater reductions in low-density lipoprotein cholesterol, triglycerides, and total cholesterol compared to the resistance training group. Exercise training, particularly aerobic interval training and resistance training, can be an effective non-pharmacological intervention for managing inflammation and improving cardiovascular health in metabolic syndrome patients.

A Moderate Walking Test Predicts Survival in Women With Cardiovascular Disease

Cardiovascular disease (CVD) is the principal cause of death in U.S. women. Peak oxygen uptake is strongly related to mortality and CVD. This study aimed to investigate the association between estimated peak oxygen uptake, determined using a moderate 1-km walking test, and all-cause mortality in female patients with stable CVD. Of the 482 women in our registry between 1997 and 2020, we included 430 participants in the analysis (aged 67 [34-88] years). A Cox proportional hazard model was used to determine the variables significantly associated with mortality. On the basis of the peak oxygen uptake estimated using the 1-km walking test, the sample was subdivided into tertiles, and mortality risk was calculated. The discriminatory accuracy of peak oxygen uptake in estimating survival was assessed by receiver operating characteristic curves. All results were adjusted for demographic and clinical covariates. A total of 135 deaths from any cause occurred over a median of 10.4 years (IQR=4.4-16.4), with an average annual mortality of 4.2%. Estimated peak oxygen uptake was a stronger predictor of all-cause mortality than demographic and clinical variables (c-statistic-0.767; 95% CI=0.72, 0.81; p<0.0001). The survival rate decreased from the highest tertile of fitness to the lowest. Compared with the lowest group, hazard ratios (95% CIs) for the second and third tertiles were 0.55 (0.37, 0.83) and 0.29 (0.16, 0.51), respectively (p for trend <0.0001). Higher peak oxygen uptake levels were associated with a lower risk of all-cause mortality. The indirect estimation of peak oxygen uptake using the 1-km walking test is feasible and can be applied for risk stratification among female patients undergoing secondary prevention programs.

Peak exercise oxygen uptake and changes in renal function in patients after acute myocardial infarction

BackgroundThe impact of exercise tolerance on renal function change after acute myocardial infarction (AMI) is not clear. ObjectivesThe present study aimed to elucidate the effect of peak exercise oxygen uptake (VO2) levels on longitudinal changes in renal function up to 1 year after onset of AMI. MethodsThis retrospective longitudinal study enrolled 198 AMI patients. Symptom-limited cardiopulmonary exercise testing was performed at completion of early Phase II cardiac rehabilitation, and peak VO2 levels were defined as the primary exposure factor. The estimated glomerular filtration rates (eGFRs) at baseline, 3 months, 6 months and 1 year were collected. Generalized estimating equation (GEE) models were used to test the longitudinal effect of peak VO2 levels on within-patient changes in eGFR. ResultsPatients were stratified into tertile groups (Low group, 12.3 ± 1.3 mL/kg/min; Mid group, 15.3 ± 0.7 mL/kg/min; and High group, 19.1 ± 2.3 mL/kg/min) according to peak VO2 levels. The slopes of eGFR over 1 year in the Low (p = 0.024) and Mid groups (p = 0.037) were lower compared to the High group. The Low group had a significantly higher odds ratio of experiencing rapid renal function decline than the High group (odds ratio, 2.87; p = 0.012). ConclusionsThere was a significant effect of lower peak VO2 on rapid decline in renal function after AMI. Our findings suggest that the coexistence of exercise intolerance may be a novel risk factor for rapid decline in renal function after AMI.

Perspectives on exercise intensity, volume, step characteristics and health outcomes in walking for transport.

Quantification of movement intensity and energy utilization, together with frequency of trips, duration, distance, step counts and cadence, is essential for interpreting the character of habitual walking for transport, and its potential support of health. The purpose of the study is to illuminate this with valid methods and novel perspectives, and to thereby provide a new basis for characterizing and interpreting walking in relation to health outcomes. Habitual middle-aged commuting pedestrians (males = 10, females = 10) were investigated in the laboratory at rest and with maximal treadmill and cycle ergometer tests. Thereafter, levels of oxygen uptake, energy expenditure, ventilation, heart rate, blood lactate, rated perceived exertion, cadence, number of steps, duration, distance, and speed were recorded during the normal walking commute of each participant in Greater Stockholm, Sweden. The number of commutes per week over the year was self-reported. Walking in the field demanded about 30% more energy per km compared to level treadmill walking. For both sexes, the walking intensity in field was about 46% of maximal oxygen uptake, and energy expenditure amounted to 0.96 kcal · kg- 1 · km- 1. The MET values (males: 6.2; females: 6.5) mirrored similar levels of walking speed (males: 5.7; females: 5.9 km · h- 1) and levels of oxygen uptake (males: 18.6; females: 19.5 mL · kg- 1 · min- 1). The average number of MET-hours per week in a typical month was 22 for males and 20 for females. This resulted in a total weekly energy expenditure of ~1,570 and 1,040 kcal for males and females, respectively. Over the year, the number of walking commutes and their accumulated distance was ~385 trips and 800 km for both sexes. Walking in naturalistic field settings demands its own studies. When males and females walk to work, their relative aerobic intensities and absolute energy demands for a given distance are similar. It is equivalent to the lower part of the moderate relative intensity domain. The combination of oxygen uptake, trip duration and frequency leads to high and sustained levels of MET-hours as well as energy expenditure per week over the year, with a clear health enhancing potential. Based on this study we recommend 6000 transport steps per day, or equivalent, during five weekdays, over the year, in order to reach optimal health gains.

Effects of L-arginine on impaired blood fluidity after high-intensity exercise: An in vitro evaluation.

Exercise-induced impairment of blood fluidity is considered to be associated with thrombosis development. However, the effects of L-arginine on blood fluidity after exercise remain unclear. We investigated the mechanisms of impaired blood fluidity after high-intensity exercise, and examined whether L-arginine improves exercise-induced blood fluidity impairment in vitro. Ten healthy male participants performed 15 minutes of ergometer exercise at 70% of their peak oxygen uptake levels. Blood samples were obtained before and after exercise. L-arginine and NG-monomethyl-L-arginine acetate (L-NMMA)-a nitric oxide (NO) synthase inhibitor-were added to the post-exercise blood samples. Using Kikuchi's microchannel method, we measured the blood passage time, percentage of obstructed microchannels, and the number of adherent white blood cells (WBCs) on the microchannel terrace. Exercise increased the hematocrit levels. The blood passage times, percentage of obstructed microchannels, and the number of adherent WBCs on the microchannel terrace increased after exercise; however, they decreased in a dose-dependent manner after the addition of L-arginine. L-NMMA inhibited the L-arginine-induced decrease in blood passage time. High-intensity exercise impairs blood fluidity by inducing hemoconcentration along with increasing platelet aggregation and WBC adhesion. The L-arginine-NO pathway improves blood fluidity impairment after high-intensity exercise in vitro.

Oxygen Uptake During Activities of Daily Life in Patients Treated With a Left Ventricular Assist Device

Oxygen consumption during activities of daily life (ADL) is not described in recipients of left ventricular assist device (LVAD). We aimed to investigate the relation between oxygen consumption during predefined ADLs and measures of functional capacity (FC) in stable-phase LVAD recipients. LVADs and controls were matched on gender, age, BMI, smoking status, and ethnicity. VO2 was measured using mobile equipment (K5, Cosmed, Rome, Italy) while putting on vest and LVAD equipment(1), folding towels(2), putting on socks and shoes(3), putting bottles in a cupboard(4), making a bed(5), walking on stairs without(6) and with extra weight(7), and sweeping the floor(8). Submaximal FC was tested by means of 6 minute walk test (6MWT) and peak oxygen uptake (pVO2) to test maximal FC. Fifteen LVAD patients and 16 controls were included; Patients were 61 ± 10years, all males with BMI 28 ± 5kg/m2 and implanted with Heartmate 3 (DT: 60%). PVO2 was 14.9 ± 2.2 ml/kg/min in patients and 39.6 ± 7.7 in controls (p < 0.001). Oxygen consumption expressed as percent of pVO2 for each task in patients vs controls was (%): ADL1: 41 ± 5 vs 21 ± 4, ADL2: 41 ± 6 vs 22 ± 5 %, ADL3: 50 ± 16 vs 24 ± 5%, ADL4: 45 ± 12 vs 22 ± 4, ADL5: 50 ± 8 vs 23 ± 4, ADL6: 66 ± 10 vs 30 ± 4, ADL7: 65 ± 10 vs 31 ± 5, ADL8: 75 ± 10 vs 39 ± 12, (p < 0.001 for all). During 6MWT LVAD patients used 96% ± 8 % of their pVO2. Recipients of durable LVADs perform daily life activities at oxygen uptake levels much closer to their peak cardiopulmonary reserve than matched healthy controls.

Is there an association between total physical activity level and VO2max among fitness club members? A cross-sectional study

BackgroundSince cardiorespiratory fitness is an important predictor for all-cause mortality, it is of interest to know if meeting the physical activity (PA) recommendations is associated with higher levels of maximal oxygen uptake (VO2max). We aimed to investigate the association between total PA level given as counts per minute (cpm) and minutes in moderate-to-vigorous PA (MVPA), and VO2max in new fitness club members.MethodsA total of 62 men and 63 women (≥ 18 years), defined as healthy (no disease considered to hinder PA) participated in this study. VO2max (mL kg−1 min−1) was measured with a cardiopulmonary exercise (modified Balke protocol), and total PA level was measured with ActiGraph GT1M for seven consecutive days. All participants accumulating ≥ 10 h of activity recordings ≥ 4 days were included in the data analysis. To examine associations between PA level and VO2max, a Pearson correlation and a multiple linear regression analysis adjusted for covariates were used.ResultsVO2max (mL kg−1 min−1) was 40.5 ± 7.2 in men and 35.1 ± 6.0 in women. Total PA level (cpm) and MVPA (min) were 352.4 ± 123.4 and 260.0 ± 132.6 in men and 361.4 ± 103.8 and 273.2 ± 137.0 in women. Total PA level (men: r = 0.346, p < 0.01, women: r = 0.267 p < 0.01) and MVPA (men: r = 0.359, p = < 0.01, women: r = 0.236, p = 0.03) was associated with VO2max. When adjusting for age and body fat percentage, total PA level and MVPA were no longer associated with VO2max (men: p = 0.11 and p = 0.79, women: p = 0.40 and p = 0.61). In men, age (β = − 0.469 p < 0.01) and body fat percentage (β = − 0.483, p < 0.01) were the strongest predictor for VO2max. For women, body fat percentage was the strongest predictor for VO2max (β = − 0.483, p < 0.01).ConclusionsTotal PA level and MVPA were associated with VO2max, but the association was low and diminished when adjusted for age and body fat percentage. Body fat percentage (men and women) and age (men) were more strongly associated with VO2max than total PA level and MVPA.

Feature Extraction and Small-Sample Learning of Dexmedetomidine for Neurosurgery on Postoperative Agitation in Patients with Craniocerebral Injury.

Objective. To observe the controlled effect of dexmedetomidine for neurosurgery and the effect on postoperative cognitive function. The main task of this paper is to use data from a small sample. The proposed feature extraction algorithm based on the bilinear convolutional neurological network (BCNN) is based on a small sample of data. BCNN involves the simultaneous extraction of highly discriminative cross-sectional features from the input image using two parallel subnetworks. By optimizing the algorithm to minimize losses, the two subnetworks can be supervised by each other, improving the performance of the network and obtaining accurate recognition results without spending a lot of time adjusting parameters. The mean arterial pressure (MAP) and heart rate (HR) levels of cerebral oxygen metabolism were compared between the two groups before (T0), after (T1), immediately after (T2), and after intubation (T3). In the observation group, MAP and HR values at T3, arterial-internal jugular vein bulb oxygen difference [D(a - jv)O 2] at T1, T2, and T3, cerebral oxygen uptake (CEO2) levels, and postawakening agitation scores were lower than those of the control group during the same period (P < 0.05).

Changes in Hippocampus and Amygdala Volume with Hypoxic Stress Related to Cardiorespiratory Fitness under a High-Altitude Environment.

The morphology of the hippocampus and amygdala can be significantly affected by a long-term hypoxia-induced inflammatory response. Cardiorespiratory fitness (CRF) has a significant effect on the neuroplasticity of the hippocampus and amygdala by countering inflammation. However, the role of CRF is still largely unclear at high altitudes. Here, we investigated brain limbic volumes in participants who had experienced long-term hypoxia exposure in Tibet (3680 m), utilizing high-resolution structural images to allow the segmentation of the hippocampus and amygdala into their constituent substructures. We recruited a total of 48 participants (48 males; aged = 20.92 ± 1.03 years) to undergo a structural 3T MRI, and the levels of maximal oxygen uptake (VO2max) were measured using a cardiorespiratory function test. Inflammatory biomarkers were also collected. The participants were divided into two groups according to the levels of median VO2max, and the analysis showed that the morphological indexes of subfields of the hippocampus and amygdala of the lower CRF group were decreased when compared with the higher CRF group. Furthermore, the multiple linear regression analysis showed that there was a higher association with inflammatory factors in the lower CRF group than that in the higher CRF group. This study suggested a significant association of CRF with hippocampus and amygdala volume, which may be related to hypoxic stress in high-altitude environments. A better CRF reduced physiological stress and a decrease in the inflammatory response was observed, which may be related to the increased oxygen transport capacity of the body.

TOXICITY OF OIL EFFLUENT ON OXYGEN UPTAKE, FILTRATION RATE AND GLYCOGEN IN Lamellidens marginalis (BIVALVIA: UNIONIDAE) UNDER LABORATORY CONDITION

Lamellidens marginalis, a freshwater bivalve, was experimentally exposed to 1/4th and 1/10th sublethal concentrations of oil effluent to examine the filtration rate, oxygen uptake, and glycogen level of foot, gill, and digestive gland tissues for healthy assessment for reuse in oil effluent intoxicated aquatic environments. The treated group's oxygen uptake was higher than the control group's by (10.43±3.476 ml oxygen/hr) in 1/4th and (11.37±3.790 ml oxygen/hr) in 1/10th exposures, which peaked at 48 hours and then declined. The concentrations of oil effluent exposure gradually increased and peaked at (205± 68.344 ml oxygen/hr) 72 hours in 1/4th and (172± 57.346 ml oxygen/hr) 42 hours in 1/10th concentrations, followed by a moderate decline trend.When compared to the control of all hours, oil effluent uptake peaked at 84 hours in 1/4th foot tissues (512±170.675 µg g-1);1/10th foot tissues (498±166.014µg g-1); 1/4th gill tissues (516±172.013 µg g-1); 1/10th gill tissues (464±154.69µg g-1) and 1/4th digestive gland tissues (540±180.012 µg g-1); 1/10th digestive gland tissues (522±174.03 µg g-1) of freshwater mussel.Mean glycogen concentrations ranged from 1.934 mg to 3.262 mg/g wet tissue in 1/4th and 2.318 mg to 3.286 mg/g wet tissue in 1/10th of sublethal exposures in foot tissues; 1.705 mg to 3.579 mg/g wet tissue in 1/4th and 2.324 mg to 3.074 mg/g wet tissue in 1/10th of exposures in gill tissues ;1.852 mg to 3.314 mg/g wet tissue in 1/4th and 1.989 mg to 3.364 mg/g wet tissues in 1/10th of exposures in digestive gland tissues. Our study concluded that the freshwater bivalve, L.marginalis can be used as biomarkers for animal health assessment and provide a new opportunity for researching the energetic reserves and health status of freshwater mussels.

Aerobic Fitness Is Associated with Cerebral μ-Opioid Receptor Activation in Healthy Humans.

Central μ-opioid receptors (MORs) modulate affective responses to physical exercise. Individuals with higher aerobic fitness report greater exercise-induced mood improvements than those with lower fitness, but the link between cardiorespiratory fitness and the MOR system remains unresolved. Here we tested whether maximal oxygen uptake (V̇O2peak) and physical activity level are associated with cerebral MOR availability and whether these phenotypes predict endogenous opioid release after a session of exercise. We studied 64 healthy lean men who performed a maximal incremental cycling test for V̇O2peak determination, completed a questionnaire assessing moderate-to-vigorous physical activity (MVPA; in minutes per week), and underwent positron emission tomography with [11C]carfentanil, a specific radioligand for MOR. A subset of 24 subjects underwent additional positron emission tomography scan also after a 1-h session of moderate-intensity exercise and 12 of them also after a bout of high-intensity interval training. Higher self-reported MVPA level predicted greater opioid release after high-intensity interval training, and both V̇O2peak and MVPA level were associated with a larger decrease in cerebral MOR binding after aerobic exercise in the ventral striatum, orbitofrontal cortex, and insula. That is, more trained individuals showed greater opioid release acutely after exercise in brain regions especially relevant for reward and cognitive processing. Fitness was not associated with MOR availability. We conclude that regular exercise training and higher aerobic fitness may induce neuroadaptation within the MOR system, which might contribute to improved emotional and behavioral responses associated with long-term exercise.

The root of the matter: nitrate-rich beetroot juice reduces skeletal muscle O2 uptake during exercise.

The root of the matter: nitrate-rich beetroot juice reduces skeletal muscle O2 uptake during exercise.

Abstract 10496: Cardiac Function in Postmenopausal Women Are Unaltered by Two Decades of Different Physical Activity Levels

Rationale: In women, the risk of coronary heart disease increases significantly after the onsetof menopause. Exercise and active lifestyle have known benefits such as a significantly reducedrisk of heart failure. To date, most of the knowledge on physical activity induced changes incardiac function in older individuals are based on males and with a sparsity of data from healthypostmenopausal women with differing physical activity and fitness. Aim: The aim was to determine the impact of more than twenty years of differing physicalactivity levels and maximal oxygen consumption on cardiac morphology and function inpostmenopausal women. Method: The study design was cross-sectional with age-matched non-smoking, non-medicatedhealthy women divided in to three groups based on their self-reported physical activity levelwith regard to intensity and volume over the past two decades. Forty-one women was included(age of 61 ± 1 years; 11 ± 2 postmenopausal years; body mass index 23 ± 3 kg • m 2 ) and dividedinto groups based on activity level categorized as sedentary (SED; ≤1 h exercise weekly; n=14);Moderate (MOD; ≥2 ≤6h low/moderate intensity exercise weekly; n=12) and high (HIGH; &lt;4h of moderate/high intensity exercise weekly; n=15). Cardiac function and dimensions wereassessed with transthoracic echocardiography and maximal pulmonary oxygen uptake wasdetermined by graded bike ergometer exercise to exhaustion. Results: The three groups displayed significantly different levels of maximum oxygen uptake(24.9 ± 5.8; 30.5 ± 5.8; 38.4 ± 4.4 ml/kg, for SED, MOD and HIGH respectively) (p &lt; 0.01).No differences were observed in resting left ventricular (LV) morphology (LVmass, LVmassindex) systolic function (EF%, GLS and mitral valve S′), diastolic function (E/A ratio, IVRT)or right ventricular function (TAPSE and tricuspid annular velocity S’) between the threegroups. Conclusions: These data show that the level of lifelong physical activity and correspondingdifferences in maximal oxygen consumption, may have less impact on left ventricularmorphology and systolic/diastolic function in healthy postmenopausal women than previouslyexpected.

Smartphone-Assisted High-Intensity Interval Training in Inflammatory Rheumatic Disease Patients: Randomized Controlled Trial.

BackgroundPatients with inflammatory rheumatic diseases (IRDs) experience disease-related barriers to physical training. Compared with the general population, IRD patients are reported to have reduced maximal oxygen uptake (VO2max) and physical activity levels. Supervised high-intensity interval training (HIIT) is documented to counteract the reduced VO2max and poor cardiovascular health associated with IRDs. However, supervised HIIT is resource demanding.ObjectiveThis study sought to investigate if self-administered 4×4-min HIIT guided by a smartphone app (Myworkout GO) could yield similar HIIT-induced effects as standard 4×4-min HIIT performed under the guidance and supervision of health care professionals. The effects studied were on VO2max and health-related quality of life (HRQoL).MethodsForty patients (33 female patients, mean age 48 years, SD 12 years; 7 male patients, mean age 52 years, SD 11 years) diagnosed with rheumatoid arthritis, spondyloarthritis, or systemic lupus erythematosus were randomized to a supervised group (SG) or an app group (AG). Both groups were instructed to perform 4×4-min intervals with a rate of perceived exertion of 16 to 17, corresponding to 85% to 95% of the maximal heart rate, twice a week for 10 weeks. Treadmill VO2max and HRQoL measured using RAND-36 were assessed before and after the exercise period.ResultsVO2max increased (P<.001) in both groups after 10 weeks of HIIT, with improvements of 3.6 (SD 1.3) mL/kg/min in the SG and 3.7 (SD 1.5) mL/kg/min in the AG. This was accompanied by increases in oxygen pulse in both groups (P<.001), with no between-group differences apparent for either measure. Improvements in the HRQoL dimensions of bodily pain, vitality, and social functioning were observed for both groups (P<.001 to P=.04). Again, no between-group differences were detected.ConclusionsHigh-intensity 4×4-min interval training increased VO2max and HRQoL, contributing to patients’ reduced cardiovascular disease risk, improved health and performance, and enhanced quality of life. Similar improvements were observed following HIIT when IRD patients were guided using perceived exertion by health care professionals or the training was self-administered and guided by the app Myworkout GO. Utilization of the app may help reduce the cost of HIIT as a treatment strategy in this patient population.Trial RegistrationClinicalTrials.gov NCT04649528; https://clinicaltrials.gov/ct2/show/NCT04649528

Prolonged Sojourn at Very High Altitude Decreases Sea-Level Anaerobic Performance, Anaerobic Threshold, and Fat Mass.

Background: The influence of high altitude on an organism’s physiology depends on the length and the level of hypoxic exposure it experiences. This study aimed to determine the effect of a prolonged sojourn at very high altitudes (above 3,500m) on subsequent sea-level physical performance, body weight, body composition, and hematological parameters.Materials and Methods: Ten alpinists, nine males and one female, with a mean age of 27±4years, participated in the study. All had been on mountaineering expeditions to 7,000m peaks, where they spent 30±1days above 3,500m with their average sojourn at 4,900±60m. Their aerobic and anaerobic performance, body weight, body composition, and hematological parameters were examined at an altitude of 100m within 7days before the expeditions and 7days after they descended below 3,500m.Results: We found a significant (p<0.01) decrease in maximal anaerobic power (MAPWAnT) from 9.9±1.3 to 9.2±1.3W·kg−1, total anaerobic work from 248.1±23.8 to 228.1±20.1J·kg−1, anaerobic threshold from 39.3±8.0 to 27.8±5.6 mlO2·kg−1·min−1, body fat mass from 14.0±3.1 to 11.5±3.3%, and a significant increase (p<0.05) in maximal tidal volume from 3.2 [3.0–3.2] to 3.5 [3.3–3.9] L after their sojourn at very high attitude. We found no significant changes in maximal aerobic power, maximal oxygen uptake, body weight, fat-free mass, total body water, hemoglobin, and hematocrit.Conclusion: A month-long exposure to very high altitude led to impaired sea-level anaerobic performance and anaerobic threshold, increased maximal tidal volume, and depleted body fat mass, but had no effect on maximal aerobic power, maximal oxygen uptake, or hemoglobin and hematocrit levels.

Randomized controlled trial of moderate cardiovascular exercise for patients with drug-resistant epilepsy

ObjectiveThe primary research question of this study was whether a moderate cardiovascular exercise program can reduce seizure frequency in patients with focal drug-resistant epilepsy (DRE). The hypothesis is that cardiovascular fitness will reduce seizure frequency in persons with epilepsy (PWE). MethodsTwenty-eight patients were randomized into two groups; exercise or relaxation. The exercise group were given an ergometric bicycle sent to their home to be used for 150 min/week, 30 min/day for 5 days a week for the study period of 6 months. Participants in the relaxation group were given audio muscular relaxation exercises to be performed for 20 min at least five times per week for the study period of 6 months. Seizure counts and exercise/relaxation sessions were registered daily in a written diary. Both groups received monthly motivational telephone calls.Seizures, anxiety, and depression symptom ratings (Hospital Anxiety and Depression Scale (HADS)), health status ratings (RAND-36), aerobic capacity (estimated VO2max), self-efficacy for exercise (SEE), level of physical activity, and adverse events were measured at the baseline and after the 6 months of intervention. CONSORT guidelines were followed. ResultsTwenty-two patients completed the intervention. There were no significant changes in seizure frequency in either of the groups. Six months of moderate exercise did increase the level of physical activity and maximal oxygen uptake. SignificanceModerate exercise did not affect seizure frequency in this study. The patients in the exercise group did increase their estimated VO2max, which is an important indicator for health, without deterioration of seizure frequency. This was accomplished with only minimal support from a physiotherapist every month. To exercise at home at a moderate intensity level with regular support may therefore be an option for patients with epilepsy. The patients in the exercise group increased their level of physical activity significantly, which indicates that they were compliant to the treatment.