High Aerobic Capacity Research Articles

Aerobic capacity modulates adaptive thermogenesis: Contribution of non-resting energy expenditure

Decreases in energy stores requires negative energy balance where caloric expenditure exceeds energy intake, which can induce adaptive thermogenesis—the reduction of energy expenditure (EE) beyond that accounted for by the weight lost. Adaptive thermogenesis varies between individuals. The component of total daily EE responsible for the interindividual variation in adaptive thermogenesis was investigated in this study, using a rat model that differs in obesity propensity and physical activity. Total daily EE and physical activity were examined before and after 21 days of 50% calorie restriction in male and female rats with lean and obesity-prone phenotypes—rats selectively bred for high and low intrinsic aerobic capacity (HCR and LCR, respectively). Calorie restriction significantly decreased EE more than was predicted by loss of weight and lean mass, demonstrating adaptive thermogenesis. Within sex, HCR and LCR did not significantly differ in resting EE. However, the calorie restriction-induced suppression in non-resting EE, which includes activity EE, was significantly greater in HCR than in LCR; this phenotypic difference was significant for both male and female rats. Calorie restriction also significantly suppressed physical activity levels more in HCR than LCR. When VO2max was assessed in male rats, calorie restriction significantly decreased O2 consumption without significantly affecting running performance (running time, distance), indicating increased energy efficiency. Percent weight loss did not significantly differ between groups. Altogether, these results suggest that individual differences in calorie restriction-induced adaptive thermogenesis may be accounted for by variation in aerobic capacity. Moreover, it is likely that activity EE, not resting or basal metabolism, may explain or predict the variation in individuals’ adaptive thermogenesis.

Impact Of 6-month Exercise Training On Neurovascular Function In Persons With Spinal Cord Injury

Accumulating evidence shows an exacerbated incidence of cognitive impairment after spinal cord injury (SCI); however, the physiology that underlies this apparent post-SCI cognitive decline is unknown. PURPOSE: To investigate the impact of injury and 6-month full-body exercise training on neurovascular coupling in individuals with SCI. METHODS: In 24 participants with SCI and 16 controls, we investigated hemodynamic (heart rate, blood pressure, CO2) and middle cerebral artery blood flow velocity responses to a working memory task (neurovascular coupling) before and after training. Neurovascular coupling was compared across groups while accounting for injury parameters. Within individuals with SCI, 6-month changes in neurovascular coupling and its relation to changes in aerobic capacity were compared via linear mixed effect model. RESULTS: Reaction time tended to be higher in individuals with SCI, especially those with high-level (≥T4) injuries, possibly due to upper motor impairments. Neurovascular coupling was graded across task difficulty (p<0.01), while injury did not have a significant impact (group effect p=0.99, interaction p=0.70). Individuals with low-level injuries (<T4) had higher aerobic capacity than those with high-level injuries (p<0.01). Aerobic capacity increased significantly with training in both groups (p<0.01). While there was no overall significant improvement in neurovascular coupling with training at the group level, the degree of improvement was closely related to that in aerobic fitness in individuals with high-level (R2=0.19, p=0.03) but not low-level (R2=0.04, p=0.46) injuries, which translated to an increase in reaction time (R2=0.16, p=0.05). CONCLUSIONS: The apparent cognitive impairment after SCI is primarily due to physical deconditioning, rather than injury itself, and can be mitigated by aerobic exercise training. This has significant implications for long-term care and management for individuals with SCI. Supported by AHA Grant 15SDG2329000 (COT), Ellen R. and Melvin J. Gordon Center for the Cure and Treatment of Paralysis (COT). EDO was in part supported by the Harvard College Research Program.

Corresponding Assessment Scenarios in Laboratory and on-Court Tests: Centrality Measurements by Complex Networks Analysis in Young Basketball Players

Besides technical and tactical aspects, basketball matches involve high aerobic and anaerobic capacities, conferring the final performance of a team. Thus, the evaluation of physical and technical responses is an effective way to predict the performance of athletes. Field and laboratory tests have been used in sports. The first involving high ecological validity and low cost, and the second, greater control and accuracy but not easy application, considering the different preparation phases in a season. This study aimed, through complex networks analysis, to verify whether centrality parameters analysed from significant correlations behave similarly in distinct scenarios (laboratory and on-court), emphasizing aerobic and anaerobic physical parameters and technical performances. The results showed that, in a compelling analysis involving basketball athletes, the studied centralities (degree, betweenness, eigenvector and pagerank) revealed similar responses in both scenarios, which is widely attractive considering the greater financial economy and lower time when applying tests in the field.

Moderate- to high intensity aerobic and resistance exercise reduces peripheral blood regulatory cell populations in older adults with rheumatoid arthritis

ObjectiveExercise can improve immune health and is beneficial for physical function in patients with rheumatoid arthritis (RA), but the immunological mechanisms are largely unknown. We evaluated the effect of moderate- to high intensity exercise with person-centred guidance on cells of the immune system, with focus on regulatory cell populations, in older adults with RA.MethodsOlder adults (≥65 years) with RA were randomized to either 20-weeks of moderate – to high intensity aerobic and resistance exercise (n = 24) or to an active control group performing home-based exercise of light intensity (n = 25). Aerobic capacity, muscle strength, DAS28 and CRP were evaluated. Blood samples were collected at baseline and after 20 weeks. The frequency of immune cells defined as adaptive regulatory populations, CD4 + Foxp3 + CD25 + CD127- T regulatory cells (Tregs) and CD19 + CD24hiCD38hi B regulatory cells (Bregs) as well as HLA-DR−/lowCD33 + CD11b + myeloid derived suppressor cells (MDSCs), were assessed using flow cytometry.ResultsAfter 20 weeks of moderate- to high intensity exercise, aerobic capacity and muscle strength were significantly improved but there were no significant changes in Disease Activity Score 28 (DAS28) or CRP. The frequency of Tregs and Bregs decreased significantly in the intervention group, but not in the active control group. The exercise intervention had no effect on MDSCs. The reduction in regulatory T cells in the intervention group was most pronounced in the female patients.ConclusionModerate- to high intensity exercise in older adults with RA led to a decreased proportion of Tregs and Bregs, but that was not associated with increased disease activity or increased inflammation.Trial registrationImproved Ability to Cope With Everyday Life Through a Person-centered Training Program in Elderly Patients With Rheumatoid Arthritis - PEP-walk Study, NCT02397798. Registered at ClinicalTrials.gov March 19, 2015.

A study on health status and physical fitness of rural women in Dharwad Taluk

Physical Fitness is the basis for dynamic and creative intellectual activity. The intelligence and skill can only function at the peak of their capacity when the body is healthy and strong. In the present situation there is need for the women to measure and analyze their physical fitness for their own benefit and improvement of health. Hence, the study was taken with the objective to analyse the health status and physical fitness of rural women. Sixty non-pregnant, non-lactating subjects without any cardio-respiratory complaints were selected for the studies were falling within the age range of 25-45 years. Maximum percentage of the women (28.33%) belonged to low weight normal category of body mass index. The mean lean body mass of the respondents was 45.91 kg and mean per cent fat was found to be 19.35 per cent. Majority of the respondents fell in the mesomorph body type. The estimation of aerobic capacity revealed that majority of the rural women (50.00%) had high average aerobic capacity of 26 to 30 ml/kg× min. The step test ergometer exercise showed that equal percentage of the respondents (33.33%) belonged to high average and low average physical fitness level.

중년 남성의 유산소 운동능력차이가 상완-발목 맥파속도 및 신체조성에 미치는 영향

The purpose of this study is to provide basic data for preventing arteriosclerosis of men by analyzing the effects of aerobic exercise capacity on arterial pulse wave velocity and body composition. The significance probability was .574 as skeletal muscle mass of the group of high aerobic exercise capacity was 31.99±3.23 and the group of low aerobic exercise capacity was 30.71±5.37.<BR> 1. For body composition, volume of body fat and visceral fat of the group of high aerobic exercise capacity was significantly lower than the group of low aerobic exercise capacity, and total weight without fat was 3.5% and basal metabolism was higher by 2.7% but did not show a significant difference.<BR> 2. For brachial ankle pulse velocity, the right side of the group of aerobic exercise capacity was significantly lower than the group of low aerobic exercise capacity and the left side was higher by 11.1% but did not show a significant difference.<BR> According to these results, obesity due to excessive accumulation of fat increases arterial wall thickness of middle-aged men, and prevention of negative changes in arterial blood vessels of obese middle-aged men is important because it causes negative changes that reduce internal carotid artery and increases the morbidity rate of cardiac disorder and cerebrovascular diseases.

A Mediterranean Lifestyle Is Associated With Lower Hypertension Prevalence and Better Aerobic Capacity Among New England Firefighter Recruits.

Examine the association between healthy Mediterranean lifestyle practices and cardiovascular disease (CVD) risk factors among New England firefighter recruits. A MEDI-Lifestyle score was used to measure adherence to a Mediterranean lifestyle (not smoking, increased physical activity, high adherence to Mediterranean diet, non-obese body mass index, decreased screen time, adequate nightly sleep, and napping) among the recruits. MEDI-Lifestyle scores were cross-sectionally analyzed with blood pressure, aerobic capacity, and other CVD risk factors. Among 92 recruits, high adherence to MEDI-Lifestyle was significantly associated with a decreased risk of prevalent hypertension (odds ratio [OR] = 0.14 [0.03-0.71]) and a greater probability of high aerobic capacity (OR = 5.80 [1.05-32.05]) as compared with low adherence in age- and sex-adjusted analyses. Increased adherence to MEDI-Lifestyle is associated with a better CVD risk profile in firefighter recruits.

Exercise intensity to maximal aerobic speed, physical activity level and heart rate variability in postmenopausal women

Physical inactivity is main cause of disease worldwide. Identify the physical exercise preference, resulting in increases adherence and future intention to perform physical activity. The preference of the intensity of exercise questionnaire (PRETIE-Q) is the main tool used to assess preference in physical exercise. Variables as age, body mass index (BMI), usual physical activity level (PAL), maximal oxygen uptake (VO2máx), can influence in PRETIE-Q answers. The purpose of this study was investigate if there is relation between preference for exercise intensity with maximal aerobic speed (MAS), PAL and heart rate variability (HRV) in postmenopausal women phase. Participated of study 30 subjects who answer PRETIE-Q together with analyses of MAS, PAL and HRV. Preference was large correlated with MAS (r = 0.63), PAL (r = 0.57) and HRVRMSSD (r = 0.52). Together, MAS (40.4%), PAL (10.7%) and HRVRMSSD (6.4%) explained 57.5% of the preference score. This results study allow to health professional, that prescribe physical exercise, understand that subjects with high aerobic capacity, cardiovagal modulation and usual PAL will have preference for high intensity exercise. In consequence, can increase the adherence to systematic practice of physical exercise. Conclude that preference of exercise intensity for women in postmenopausal phase is related with aerobic capacity, high HRV and physical activity level.

Female Rats Artificially Selected for Low and High Intrinsic Aerobic Capacity Swap Inflammatory Cascade in Resistance Arteries: Mechanisms of Cyclooxygenase‐Derived Prostanoids

Low‐capacity runner (LCR) rats and high‐capacity runner (HCR) rats are translational models of human physiology as they present a genetic predisposition towards disease and the ultra‐healthy state, respectively. Selected for their low (LCR) and high (HCR) intrinsic aerobic capacity, LCR rats display increased risk of metabolic syndrome and vascular inflammation, whereas HCR rats have decreased risk factors. Cyclooxygenase (COX) is an enzyme that plays a key role in inflammation as well as normal vascular physiology; however, it is unknown if rats with low or high intrinsic capacity present differences in the COX‐induced inflammatory cascade. As obese females display an increased risk to cardiovascular disease compared to males, female LCR rats were used as a model for metabolic syndrome. Therefore, we hypothesized that resistance arteries from female LCR rats would show increased COX activity, while arteries from female HCR rats would show decreased COX activity.Our rat model (female, 18–25 weeks old) study used LCR, HCR, and high‐response trained (HRT) rats as control (n=4/group). HRT rats have a trained aerobic capacity that is higher than LCR but lower than HCR. We quantified cardiac hypertrophy by dividing the left ventricle weight by 26.73 + tibia length (TL)3. Statistics: t‐test: p&lt;0.05: * vs control (HRT); # vs. HCR; &amp; vs. absence of indomethacin (Indo). No differences in fat pad weight between HRT and HCR were observed. However, LCR rats showed increased fat pad weight when compared to HCR [HRT: 1.05±0.2 vs. LCR: 1.57±0.2#; HCR: 0.92±0.1 (g)]. As expected, HCR presented an increased left ventricle weight, indicating physiologic hypertrophy, when compared to LCR. No differences were observed between LCR and control [HRT: 6.84±0.9 vs. LCR: 6.55±0.1#; HCR: 7.73±0.3; 26.73+TL3]. Mesenteric resistance arteries (MRA) were extracted and mounted onto a wire myograph. No significant differences were observed in the acetylcholine and phenylephrine (PE) concentration‐response curves between groups. As expected, arteries from HRT and LCR rats incubated with a nonspecific COX inhibitor [indomethacin (Indo), 10 μM] presented a significant decrease in contraction. Interestingly, indomethacin did not alter or decrease phenylephrine‐induced contraction in arteries from HCR [PE: Emax%: HRT: control 93±3 vs. Indo 3±0.6&amp;; LCR: control 62±17 vs. Indo 2±0.7&amp;; HCR: control 94±6 vs. Indo 80±9] (Fig 1). Overall, these data reveal a new, dichotomous mechanism for vascular inflammation and contractility in LCR and HCR rats. Specifically, we observed that arteries from female rats born with high aerobic capacity are unresponsive to COX inhibition during phenylephrine contraction, perhaps to maintain the high vascular flow needed for their higher exercise metabolism. This may be caused by a swap mechanism from a normal inflammatory state to a higher inflammatory‐resolution state. Our study constitutes the basis for the discovery of new therapeutic targets for vascular inflammation in people with high aerobic capacity.Support or Funding InformationThis work was supported by National Institutes of Health (NIH) (NIH: R00GM118885)Concentration‐response curves to phenylephrine, with and without indomethacin (10 uM), in mesenteric resistance arteries (MRA) from (A) HRT, (B) LCR, and (C) HCR rats. (D) The average maximum response (Emax) of MRA to phenylephrine, with and without indomethacin (10 uM). T‐test: &amp; vs. absence of Indo p&lt;0.05.Figure 1

Augmented Cardiac Mitochondrial Capacity in High Aerobic Capacity “Disease Resistant” Phenotype at Rest is Lost Following Ischemia Reperfusion

RationaleIschemic heart disease is a major cause of morbidity. Regular active exercise is therapeutic, but up to 70% of individual exercise capacity is due to an intrinsic genetic component. Intrinsic capacity can be studied using high (HCR) and low (LCR) aerobic running capacity rat strains. The phenotypes differ by more than 5 fold in sedentary average running distance and time. The HCR rats have been characterized as “disease resistant”, while the LCRs are characterized as “disease prone”. A consistent characteristic of the LCR is reduced metabolic capacity in several tissues, but metabolic capacity in cardiac tissue is not well studied in these phenotypes, particularly following the metabolic stress of ischemia and reperfusion.Methods32 HCR and LCR rats were obtained from the parent colony at the University of Toledo, housed under sedentary conditions, and fed normal chow. LCR and HCR animals were randomly assigned to either control (C, n = 8 each) or ischemia reperfusion (IR, n = 8 each). On each study day, one HCR/LCR pair was anesthetized and hearts were rapidly excised. In IR animals, the hearts were immediately flushed with iced hyperkalemic, hyperosmotic, cardioplegia solution, and subjected to cold global ischemic arrest (80 min). Following arrest, the hearts underwent warm reperfusion (120 min) using a Langendorff style perfusion system. Following reperfusion, the heart was weighed and the LV was isolated. A mid ventricular ring was obtained to estimate infarction size (TTC), and part of the remaining tissue (~150 mg) was transferred to homogenation buffer on ice. Isolated mitochondria (MITO) samples were prepared and used to determine respiratory capacity under different metabolic conditions (OROBOROS). MITO from control animals were obtained and prepared in similar fashion, but immediately following anesthesia and heart removal, and without IR. Citrate synthase activity was measured in each sample.ResultsIn the control rats, HCR MITO showed respiratory rates 32% higher at rest and more than 40% higher under maximally stimulated conditions, compared to LCR MITO (both p &lt; 0.05). After IR, resting MITO respiratory rates were decreased to about 10% in both strains, and the augmented capacity in HCRs was absent. Maximally stimulated rates also were decreased more than 50% from control, and were no longer different between phenotypes. Infarct size was not significantly different between HCR and LCR (49.2% ± 5.6 vs. 53.7% ± 4.9), nor was average coronary flow during reperfusion.ConclusionCardiac mitochondria from HCR were significantly higher in control conditions with each substrate tested. After IR insult, the cardiac mitochondrial respiratory rates were similar between phenotypes, as was infract size. Relatively, the loss of respiratory capacity was actually greater in HCR than LCR. Together, these data could suggest limits in the extent to which the HCR phenotype might be “protective” against acute tissue stressors. The extent to which any of these deficits could be “rescued” by an active exercise component is unknown.

Differential Receptor‐Mediated Inducible Gene Expression in Post Infarction Cardiac Fibroblasts is Altered by Intrinsic Exercise Phenotype

BackgroundIschemic heart disease is a major cause of morbidity. Regular active exercise is therapeutic after myocardial infarction, but up to 70% of individual exercise capacity is due to an intrinsic genetic component. Intrinsic capacity can be studied using high (HCR) and low (LCR) aerobic running capacity rat strains. The phenotypes differ by more than 5 fold in sedentary average running distance and time. The HCR rats have been characterized as “disease resistant”, while the LCRs are characterized as “disease prone”. In the heart, cardiac fibroblasts play a critical role in healing post myocardial infarction, but little is known about the effect of intrinsic aerobic capacity on the inducible, receptor‐mediated fibroblast gene expression pathways following ischemia reperfusion.MethodsOn each study day, one HCR/LCR pair (n = 8 each) was anesthetized and hearts were rapidly excised. The hearts were immediately flushed with iced hyperkalemic, hyperosmotic, cardioplegia solution, and subjected to cold global ischemic arrest (80 min). Following arrest, the hearts underwent warm reperfusion (120 min) using a Langendorff style perfusion system. Following reperfusion, the heart was weighed and the LV was isolated. A mid ventricular ring was obtained to estimate infarction size (TTC), and part of the remaining tissue (~150 mg) was transferred to homogenation buffer on ice for subsequent isolation of fibroblasts. Cardiac fibroblasts from the LV of HCRs and LCR rats were isolated, and cultured in 6 well plates. Different wells were treated with BMP7, Angiotensin or both, with or without receptor antagonists (BMP2R, noggin; AngR, Losartan). After conditioning, RNA was isolated from the cultured fibroblasts, and RT‐PCR was used to determine baseline gene expression for Collagen I and III, MMP2, TIMP1, BMPR2, ATR1, SMAD5, and Bag3 in each phenotype.ResultsOverall, Collagen I gene expression was significantly higher in LCRs more than HCRs, but the activating pathways were phenotype dependent. Treating with Ang II induced gene expression for collagen I in LCR fibroblasts but not HCR, and was completely blocked with Losartan. By Contrast, treating with BMP7 induced gene expression of collagen I in HCR fibroblasts but not LCRs, and was completely blocked by noggin. Treating the fibroblasts with a combination of receptor agonists confirmed the phenotypic selectivity of the inducible pathways. Inhibiting BMP7 using noggin brought collagen I gene expression back to the control level with no changes in LCRs.ConclusionThe Angiotensin receptor pathway is responsive only in post‐ischemic LCR cardiac fibroblasts, and the BMP receptor pathway is responsive only in post‐ischemic HCR cardiac fibroblasts. How the intrinsic aerobic phenotype governs these pathways is unknown, but could shed new light on individuals who develop post‐infraction fibrosis despite therapeutic dosing with Angiotensin pathway antagonists.

Relative Profibrotic Gene Expression in Cardiac Fibroblasts from Low Aerobic Capacity “Disease Prone” Rats Following Ischemic Reperfusion

BackgroundIschemic heart disease is a major cause of morbidity. Regular active exercise is therapeutic after myocardial infarction, but up to 70% of individual exercise capacity is due to an intrinsic genetic component. Intrinsic capacity can be studied using high (HCR) and low (LCR) aerobic running capacity rat strains. The phenotypes differ by more than 5 fold in sedentary average running distance and time. The HCR rats have been characterized as “disease resistant”, while the LCRs are characterized as “disease prone”. In the heart, cardiac fibroblasts play a critical role in healing post myocardial infarction, but little is known about the effect of intrinsic aerobic capacity on early fibroblast gene expression following ischemia reperfusion.MethodsOn each study day, one HCR/LCR pair (n = 8 each) was anesthetized and hearts were rapidly excised. The hearts were immediately flushed with iced hyperkalemic, hyperosmotic, cardioplegia solution, and subjected to cold global ischemic arrest (80 min). Following arrest, the hearts underwent warm reperfusion (120 min) using a Langendorff style perfusion system. Following reperfusion, the heart was weighed and the LV was isolated. A mid ventricular ring was obtained to estimate infarction size (TTC), and part of the remaining tissue (~150 mg) was transferred to homogenation buffer on ice for subsequent isolation of fibroblasts. Cardiac fibroblasts from the LV of HCRs and LCR rats were isolated, cultured and characterized. Immunohistochemistry verified fibroblasts/myofibroblasts markers. RNA was isolated from the cultured fibroblasts, and RT‐PCR was used to determine baseline gene expression for Collagen I and III, MMP2, TIMP1, BMPR2, ATR1, SMAD5, and Bag3 in each phenotype.ResultsImmunocytochemistry successfully confirmed the presence of both fibroblasts and myofibroblasts markers. In these post IR fibroblast/myofibroblasts, LCRs showed significantly higher gene expression (49%) in the collagen I/collagen III ratio but lower expression of extracellular matrix regulatory genes including MMP2 (20%), TIMP1 (17%), and SMAD5 (15%) compared to HCRs counterparts. BMPR2 (50%), Agtr1a (25%), also were both decreased, and the anti‐apoptotic gene, Bag3, was significantly (67%) higher in LCRs.ConclusionThese results indicate that the LCR phenotype is predisposed to expressing a more fibrotic character in fibroblasts harvested immediately following IR, and may indicate poorer long term outcome/earlier onset heart failure following acute ischemic injury to the heart. While the phenotype produced no differences in the acute injury, there may be phenotypic differences that develop later during resolution of the injury.

Running economy and its correlation to performance and fitness variables in recreationally-trained distance runners

Specific physiological attributes such as maximal oxygen consumption (VO2max) and running economy (RE) have been suggested to help predict long distance performance in endurance athletes. Despite this, investigations of RE have yielded conflicting results, particularly when comparing elite and recreational runners. The purpose of this study was to illustrate correlations between RE, expressed as submaximal oxygen consumption at a given speed, and time trial (TT) performance in addition to various fitness markers in endurance-trained individuals. Trained distance runners (n=21) performed a battery of tests over three sessions to provide measurements of RE at 2.68 m/s (RE2.68) and 4.25 m/s (RE4.25), TT performance, VO2max, velocity at ventilatory threshold (VVT), and body composition. Pearson-product moment correlations, defined as weak (r≥0.25), moderate (r≥0.45), and strong (r≥0.65), were calculated among all measures and significance was set at P&lt;0.05. The findings suggested that faster TT performance was significantly (P&lt;0.05) correlated to a higher VO2max (r=-0.86) and lower body fat percentage (BF%; r=0.78). However, TT performance displayed only a weak trend to RE4.25 (r=-0.40, P=0.07) and was not correlated to RE2.68 (r=0.15; P&gt;0.05). Additionally, better RE4.25 (i.e. decreased submaximal oxygen consumption) was associated with a lower VO2max (r=0.66, P&lt;0.05) and an increased BF% (r=-0.46, P&lt;0.05). RE2.68 revealed no significant relationships with these measures. Comparable to their elite counterparts, higher aerobic capacity is strongly linked to performance in recreational distance runners, though in this cohort RE only weakly related to performance at the faster velocity. Finally, the inverse relationship between markers of overall fitness and RE suggests that enhanced RE may be an adaptive response to a limited physiological capacity in this population.

Aerobic fitness, Mediterranean diet and cardiometabolic risk factors in adults

IntroductionUnhealthy lifestyle and inadequate diet could influence the development of future cardiometabolic disease. The main aim of this study was to determine the association between aerobic fitness and cardiometabolic risk factors in adults, whether this relation is depends of adherence to Mediterranean diet (MD). A secondary aim was to study the combined effect of aerobic capacity and adherence to MD on global cardiometabolic risk score (CMRS). MethodA total of 79 adults (38% women) enrolled between 18–40 year from Cádiz. We measured adiposity indicators, blood pressure, triglycerides, glucose and inflammatory profile (interleukin-6 and tumor necrosis factor) and was computed (CMRS). Aerobic fitness was measured by maximal oxygen comsuption through an incremental stress test by cycleergometer. The MD patterns was measured using the questionnaire of adherence to MD. The association between aerobic fitness and cardiometabolic risk factors was examined using a lineal regression and it was adjusted for different confounders. CMRS on the lifestyle was analyzed using the ANOVA test, with statistical significance level of p<0.05 in Bonferroni. ResultsLinear regression showed inverse association between aerobic fitness and cardiometabolic risk factors (all p≤0.05) in the model without adjustment. Blood pressure and triglycerides lost the association after adjust model for sex, age, and adherence to MD. Participants with high aerobic fitness and high adherence to MD show a lowest CMRS (−1.083±2.325 vs. 2.802±1.759). ConclusionsAerobic fitness was inversely associated with fatness risk factors, that relationship is independent to adherence to MD. A high adherence to MD could modulate blood pressure. A combination of high aerobic capacity and high adherence to MD could reduce the adverse consecuence of a low adherencie to MD.

Aerobic capacity is associated with disease activity and cardiovascular risk factors in early rheumatoid arthritis.

ObjectivesThe aim of this study was to investigate aerobic capacity and its associations with disease activity and risk factors for cardiovascular disease (CVD) in early rheumatoid arthritis (RA).MethodsThis cross‐sectional study included 67 patients with early RA. Aerobic capacity was estimated with the Åstrand submaximal test adjusted according to the Nord‐Tröndelag Health Study formula. The following were also assessed: subclinical atherosclerosis by carotid intima‐media thickness and pulse wave analysis; body composition by dual X‐ray absorptiometry; estimated CVD mortality risk by the Systematic Coronary Risk Evaluation; disease activity by the Disease Activity Score 28, C‐reactive protein and erythrocyte sedimentation rate; blood lipids by total cholesterol, low‐density lipoproteins, high‐density lipoproteins, and triglycerides; and functional ability by the Stanford health assessment questionnaire. Univariate and multiple linear regression analyses were performed to explore the associations between variables.ResultsThe mean (SD) aerobic capacity was 31.6 (8.7) ml O2 −1 kg min−1. Disease activity and risk factors for CVD were more favourable for patients with aerobic capacity above the median value. Aerobic capacity was associated with ESR and several CVD risk factors, independent of age and sex. In a multiple regression model that was adjusted for age and sex, aerobic capacity was significantly associated with per cent body fat (β = −0.502, 95% CI [−0.671, −0.333]) and triglycerides (β = −2.365, 95% CI [−4.252, −0.479]).ConclusionsDisease activity and risk factors for CVD were in favour for patients with a higher aerobic capacity. Aerobic capacity was associated with disease activity and several risk factors for CVD, independent of age and sex. In RA, these findings may provide insights into the benefits of using aerobic capacity as a marker to prevent CVD.

Interspecific differences and ecological correlations of energy metabolism traits in freshwater fishes

Abstract Metabolic energy fuels all biological processes, and thus, energy metabolism is vitally important for organisms. It has been suggested that interspecific variation in physiological functions is associated with the energetic metabolism of organisms, which varies considerably due to selection, adaptation and evolution. Thus, the present study aimed to clarify the relationship between the interspecific diversification of maintenance energy expenditure and two forms of anaerobic capacity (in terms of exercise and hypoxia tolerance) in freshwater fishes. Moreover, in the context of environmental adaptation, we hypothesized that selection for increased locomotor performance in species with a fast‐flow lifestyle favours a high aerobic and anaerobic capacity and, consequently, a high maintenance metabolism, whereas selection for strong hypoxia tolerance in species with a slow‐flow lifestyle favours a reduced maintenance metabolism and a reduced aerobic capacity. We examined these topics among 30 species of freshwater fish with different lifestyles based on the flow regimes of their habitats (fast, intermediate and slow flow). The resting metabolic rate of each species was measured, and then, the fish were subjected to two treatments: (a) exercise to exhaustion, after which we measured the maximum metabolic rate, excess post‐exercise oxygen consumption and metabolic recovery rate; and (b) hypoxia to the point of loss of equilibrium (LOE), after which we measured the metabolic response to recovery from hypoxia, including the peak metabolic rate (PMRh) and the excess post‐hypoxia oxygen consumption (EPOCh). We found that the resting metabolic rate was positively correlated with both the aerobic and anaerobic capacity of the fishes and that species from fast‐flow habitats have higher aerobic and anaerobic capacity with concomitantly increased resting metabolism. However, neither EPOCh nor LOE was correlated with resting metabolic rate. In summary, we suggest that selection for increased aerobic and anaerobic capacity to facilitate the demands of exercise has occurred in fast‐flow species, that selection for hypoxia tolerance may have favoured a reduction in this capacity in intermediate and slow‐flow species, and that specialized adaptations (such as flexibility in gill morphology and altered metabolic pathways) play important roles in hypoxia tolerance in some species. A free Plain Language Summary can be found within the Supporting Information of this article.

Rats genetically selected for low and high aerobic capacity exhibit altered soleus muscle myofilament functions.

Aerobic exercise capacity is critical to bodily health. As a model to investigate the mechanisms that determine health and disease, we employed low (LCR) and high (HCR) capacity running rat models selectively bred to concentrate the genes responsible for divergent aerobic running capacity. To investigate the skeletal muscle contribution to this innate difference in running capacity we employed an approach combining examination of the myofilament protein composition and contractile properties of the fast fiber extensor digitorum longus (EDL) and slow fiber soleus (SOL) muscles from LCR and HCR rats. Intact muscle force experiments demonstrate that SOL, but not EDL, muscles from LCR rats exhibit a three times greater decrease in fatigued force. To investigate the mechanism of this increased fatigability in the LCR SOL muscle, we determined the myofilament protein composition and functional properties. Force-Ca2+ measurements demonstrate decreased Ca2+ sensitivity of single skinned SOL muscle fibers from LCR compared with that of HCR rats. Segregating SOL fibers into fast and slow types demonstrates that the decreased Ca2+ sensitivity in LCR SOL results from a specific decrease in slow-type SOL fiber Ca2+ sensitivity such that it was similar to that of fast-type fibers. These results identify that the altered myofilament contractile properties of LCR SOL slow-type fibers result in a fast muscle type Ca2+ sensitivity and the LCR muscle phenotype. Overall our findings demonstrate alterations of the myofilament proteins could contribute to fatigability of the SOL muscle and the decreased innate aerobic running performance of LCR compared with HCR rats.

Energetic constraints on mammalian home‐range size

Abstract The metabolic theory of ecology predicts that rates of metabolic processes play a central role in constraining important fitness traits such as home‐range size. Locomotory behaviours are physiologically expensive, yet the relative importance of the animal's energetics in determining their home ranges is unknown. It is tested here whether maintenance costs (BMR; basal metabolic rate), energetic capacity (VO2max; maximum metabolic rate) or available energy above self‐maintenance (aerobic scope) are related to the size of mammalian home ranges using phylogenetic comparative methods. The first quantitative support for the hypothesis that home‐range size is limited by metabolic rates, accounting for variation in body mass, is presented. In particular, the negative effect of BMR, along with the positive effect of VO2max, on home‐range size revealed that aerobic scope plays a prominent role in constraining home ranges. These findings suggest optimization of energy allocation where past selection promoted an increase in mobility at the lowest possible body maintenance costs. High aerobic capacity is needed to operate large home ranges. However, in habitats of limited productivity, the associated increase in self‐maintenance constrains energy allocation to locomotory behaviours, reinforcing the importance of metabolic processes in ecology. A free Plain Language Summary can be found within the Supporting Information of this article.

Association of EGLN1 gene with high aerobic capacity of Peruvian Quechua at high altitude

Highland native Andeans have resided at altitude for millennia. They display high aerobic capacity (VO2max) at altitude, which may be a reflection of genetic adaptation to hypoxia. Previous genomewide (GW) scans for natural selection have nominated Egl-9 homolog 1 gene (EGLN1) as a candidate gene. The encoded protein, EGLN1/PHD2, is an O2 sensor that controls levels of the Hypoxia Inducible Factor-α (HIF-α), which regulates the cellular response to hypoxia. From GW association and analysis of covariance performed on a total sample of 429 Peruvian Quechua and 94 US lowland referents, we identified 5 EGLN1 SNPs associated with higher VO2max (L⋅min-1 and mL⋅min-1⋅kg-1) in hypoxia (rs1769793, rs2064766, rs2437150, rs2491403, rs479200). For 4 of these SNPs, Quechua had the highest frequency of the advantageous (high VO2max) allele compared with 25 diverse lowland comparison populations from the 1000 Genomes Project. Genotype effects were substantial, with high versus low VO2max genotype categories differing by ∼11% (e.g., for rs1769793 SNP genotype TT = 34.2 mL⋅min-1⋅kg-1 vs. CC = 30.5 mL⋅min-1⋅kg-1). To guard against spurious association, we controlled for population stratification. Findings were replicated for EGLN1 SNP rs1769793 in an independent Andean sample collected in 2002. These findings contextualize previous reports of natural selection at EGLN1 in Andeans, and support the hypothesis that natural selection has increased the frequency of an EGLN1 causal variant that enhances O2 delivery or use during exercise at altitude in Peruvian Quechua.

Transcriptome analysis reveals a high aerobic capacity in the whale brain

The brain of diving mammals is repeatedly exposed to low oxygen conditions (hypoxia) that would have caused severe damage to most terrestrial mammals. Some whales may dive for >2 h with their brain remaining active. Many of the physiological adaptations of whales to diving have been investigated, but little is known about the molecular mechanisms that enable their brain to survive sometimes prolonged periods of hypoxia. Here, we have used an RNA-Seq approach to compare the mRNA levels in the brains of whales with those of cattle, which serves as a terrestrial relative. We sequenced the transcriptomes of the brains from cattle (Bos taurus), killer whale (Orcinus orca), and long-finned pilot whale (Globicephala melas). Further, the brain transcriptomes of cattle, minke whale (Balaenoptera acutorostrata) and bowhead whale (Balaena mysticetus), which were available in the databases, were included. We found a high expression of genes related to oxidative phosphorylation and the respiratory electron chain in the whale brains. In the visual cortex of whales, transcripts related to the detoxification of reactive oxygen species were more highly expressed than in the visual cortex of cattle. These findings indicate a high oxidative capacity in the whale brain that might help to maintain aerobic metabolism in periods of reduced oxygen availability during dives.