Subpopulations of regulatory T cells are associated with subclinical atherosclerotic plaques,levels of LDL,and cardiorespiratory fitness in the elderly

Background:Atherosclerosis forms the pathological basis for the development of cardiovascular disease.Since pathological processes initially develop without clinically relevant symptoms,the identification of early markers in the subclinical stage plays an important role for initiating early interventions.There is evidence that regulatory T cells(Tregs)are involved in the development of atherosclerosis.Therefore,the present study aimed to identify and investigate associations with Tregs and their subsets in a cohort of healthy elderly individuals with and without subclinical atherosclerotic plaques(SAP).In addition,various lifestyle and risk factors,such as cardiorespiratory fitness,were investigated as associated signatures.Methods:A cross-sectional study was performed in 79 participants(male:n=50;age=63.6±3.7 years;body mass index=24.9±3.1 kg/m2;mean±SD)who had no previous diagnosis of chronic disease and were not taking medication.Ultrasound of the carotids to identify SAP,cardiovascular function measurement for vascular assessment and a cardiorespiratory fitness test to determine peak oxygen uptake were performed.Additionally,tests were conducted to assess blood lipids and determine glucose levels.Immunophenotyping of Tregs and their subtypes(resting(rTregs)and effector/memory(mTregs))was performed by 8-chanel flow cytometry.Participants were categorized according to atherosclerotic plaque status.Linear and logistic regression models were used to analyze associations between parameters.Results:SAP was detected in a total of 29 participants.The participants with plaque were older(64.8±3.6 years vs.62.9±3.5 years)and had higher peripheral systolic blood pressure(133.8±14.7 mmHg vs.125.8±10.9 mmHg).The participants with SAP were characterized by a lower percentage of rTregs(28.8%±10.7%vs.34.6%±10.7%)and a higher percentage of mTregs(40.3%±14.7%vs.30.0%±11.9%).Multiple logistic regression identified age(odds ratio(OR)=1.20(95%confidence interval(95%CI):1.011.42))and mTregs(OR=1.05(95%CI:1.021.10))as independent risk factors for SAP.Stepwise linear regression could reveal an association of peak oxygen uptake(β=0.441),low-density lipoprotein(LDL)(β=0.096),and SAP(β=6.733)with mTregs and LDL(β=0.104)with rTregs.Conclusion:While at an early stage of SAP,the total proportion of Tregs gives no indication of vascular changes,this is indicated by a shift in the Treg subgroups.Factors such as serum LDL or cardiopulmonary fitness may be associated with this shift and may also be additional diagnostic indicators.This could be used to initiate lifestyle-based preventive measures at an early stage,which may have a protective effect against disease progression.

Association between cardiorespiratory fitness level and insulin resistance in adolescents with various obesity categories

BACKGROUND An association between cardiorespiratory fitness(CRF)and insulin resistance in obese adolescents,especially in those with various obesity categories,has not been systematically studied.There is a lack of knowledge about the effects of CRF on insulin resistance in severely obese adolescents,despite their continuous rise.AIM To investigate the association between CRF and insulin resistance in obese adolescents,with special emphasis on severely obese adolescents.METHODS We performed a prospective,cross-sectional study that included 200 pubertal adolescents,10 years to 18 years of age,who were referred to a tertiary care center due to obesity.According to body mass index(BMI),adolescents were classified as mildly obese(BMI 100% to 120% of the 95^(th)percentile for age and sex)or severely obese(BMI≥120% of the 95^(th)percentile for age and sex or≥35 kg/m^(2),whichever was lower).Participant body composition was assessed by bioelectrical impedance analysis.A homeostatic model assessment of insulin resistance(HOMA-IR)was calculated.Maximal oxygen uptake(VO_(2)max)was determined from submaximal treadmill exercise test.CRF was expressed as VO_(2)max scaled by total body weight(TBW)(mL/min/kg TBW)or by fat free mass(FFM)(mL/min/kg FFM),and then categorized as poor,intermediate,or good,according to VO_(2)max terciles.Data were analyzed by statistical software package SPSS(IBM SPSS Statistics for Windows,Version 24.0).P<0.05 was considered statistically significant.RESULTS A weak negative correlation between CRF and HOMA-IR was found[Spearman’s rank correlation coefficient(rs)=-0.28,P<0.01 for CRF_(TBW);(r_(s))=-0.21,P<0.01 for CRF_(FFM)].One-way analysis of variance(ANOVA)revealed a significant main effect of CRF on HOMA-IR[F(2200)=6.840,P=0.001 for CRF_(TBW);F_((2200))=3.883,P=0.022 for CRF_(FFM)].Subsequent analyses showed that obese adolescents with poor CRF had higher HOMA-IR than obese adolescents with good CRF(P=0.001 for CRF_(TBW);P=0.018 for CRF_(FFM)).Two-way ANOVA with Bonferroni correction confirmed significant effect of interaction of CRF level and obesity category on HOMA-IR[F_((2200))=3.292,P=0.039 for CRF_(TBW)].Severely obese adolescents had higher HOMA-IR than those who were mildly obese,with either good or poor CRF.However,HOMA-IR did not differ between severely obese adolescents with good and mildly obese adolescents with poor CRF.CONCLUSION CRF is an important determinant of insulin resistance in obese adolescents,regardless of obesity category.Therefore,CRF assessment should be a part of diagnostic procedure,and its improvement should be a therapeutic goal.

Comparison of the effects of high-intensity interval and moderate-intensity continuous training on inflammatory markers,cardiorespiratory fitness,and quality of life in breast cancer patients

Background:As the effectiveness of breast cancer treatment has improved,a growing number of long-term breast cancer survivors are seeking help for unique health problems.These patients may be at increased risk of cardiovascular disease due to the side effects of treatment.The positive impact of most types of exercise has been repeatedly reported in people with cancer,but the most effective exercise approaches for maximum beneficial adaptations remain controversial.Thus,this study aimed to compare the effects of high-intensity interval training(HIIT)and moderate-intensity continuous training(MICT) on inflammatory indices,adipokines,metabolic markers,body composition,cardiorespiratory fitness,and quality of life in breast cancer patients during adjuvant endocrine therapy.Methods:Thirty non-metastatic breast cancer patients during adjuvant endocrine therapy who had been treated with chemotherapy and/or radiotherapy were recruited from Iran and randomized to HIIT,MICT,or control groups for a supervised exercise intervention that took place 3 times a week for 12 weeks.The training intensity was determed based on the peak oxygen uptake(VO2peak),and the volume of training was matched in HIIT and MICT based on the VO2peak.Body composition,functional capacity,cardiorespiratory fitness,metabolic indices,sex hormones,adipokines,and inflammatory markers were assessed before and after the intervention.Results:The VO2peakincreased by 16.8% in the HIIT group in comparison to baseline values(mean difference=3.61 mL/kg/min).HIIT significantly improved the VO2peakcompared to control(mean difference=3.609 mL/kg/min) and MICT(mean differences=2.974 mL/kg/min)groups.Both HIIT(mean difference=9.172 mg/dL) and MICT(mean difference=7.879 mg/dL) interventions significantly increased highdensity lipoprotein cholesterol levels compared to the control group.The analysis of covariance showed that physical well-being significantly improved in MICT compared to control group(mean difference=3.268).HIIT significantly improved the social well-being compared to the control group(mean difference=4.412).Emotional well-being subscale was significantly improved in both MICT(mean difference=4.248)and HIIT(mean difference=4.412) compared to the control group.Functional well-being scores significantly increased in HIIT group compared with control group(mean difference=3.35).Significant increase were also observed in total functional assessment of cancer therapy-General scores in both HIIT(mean difference=14.204) and MICT groups(mean difference=10.036) compared with control group.The serum level of suppressor of cytokine signaling 3 increased significantly(mean difference=0.09 pg/mL) in the HIIT group compared to the baseline.There were no significant differences between groups for body weight,body mass index,fasting blood glucose,insulin resistance,sex hormone binding globulin,total cholesterol,low-density lipoprotein cholesterol,adipokines,interleukin-6,tumor necrosis factor-a,or interleukin-10.Conclusion:HIIT can be used as a safe,feasible,and time-efficient intervention to improve cardiovascular fitness in breast cancer patients.Both HIIT and MICT modalities enhance quality of life.Further large-scale studies will help determine whether these promising results translate into improved clinical and oncological outcomes.

Effectiveness of high intensity interval training on cardiorespiratory fitness and endothelial function in type 2 diabetes:A systematic review

BACKGROUND Type 2 diabetes mellitus(T2DM)is a chronic metabolic syndrome characterized by insulin resistance and hyperglycemia that may lead to endothelial dysfunction,reduced functional capacity and exercise intolerance.Regular aerobic exercise has been promoted as the most beneficial non-pharmacological treatment of cardiovascular diseases.High intensity interval training(HIIT)seems to be superior than moderate-intensity continuous training(MICT)in cardiovascular diseases by improving brachial artery flow-mediated dilation(FMD)and cardiorespiratory fitness to a greater extent.However,the beneficial effects of HIIT in patients with T2DM still remain under investigation and number of studies is limited.AIM To evaluate the effectiveness of high intensity interval training on cardiorespiratory fitness and endothelial function in patients with T2DM.METHODS We performed a search on PubMed,PEDro and CINAHL databases,selecting papers published between December 2012 and December 2022 and identified published randomized controlled trials(RCTs)in the English language that included community or outpatient exercise training programs in patients with T2DM.RCTs were assessed for methodological rigor and risk of bias via the Physiotherapy Evidence Database(PEDro).The primary outcome was peak VO_(2 ) and the secondary outcome was endothelial function assessed either by FMD or other indices of microcirculation.RESULTS Twelve studies were included in our systematic review.The 12 RCTs resulted in 661 participants in total.HIIT was performed in 310 patients(46.8%),MICT to 271 and the rest 80 belonged to the control group.Peak VO_(2 ) increased in 10 out of 12 studies after HIIT.Ten studies compared HIIT with other exercise regimens(MICT or strength endurance)and 4 of them demonstrated additional beneficial effects of HIIT over MICT or other exercise regimens.Moreover,4 studies explored the effects of HIIT on endothelial function and FMD in T2DM patients.In 2 of them,HIIT further improved endothelial function compared to MICT and/or the control group while in the rest 2 studies no differences between HIIT and MICT were observed.CONCLUSION Regular aerobic exercise training has beneficial effects on cardiorespiratory fitness and endothelial function in T2DM patients.HIIT may be superior by improving these parameters to a greater extent than MICT.

Effect of Exercise-Based Cardiac Rehabilitation on Cardiorespiratory Fitness in Adults with Congenital Heart Disease

Background:The purpose of this study was to investigate whether patients with adult congenital heart disease(ACHD)benefit from exercise-based cardiac rehabilitation(CR)short-and long-term with regard to improvement of cardiorespiratory fitness.Methods:Cardiopulmonary exercise tests(CPET)completed by ACHD patients between January 2000 and October 2019 were analysed retrospectively.Linear mixed models were performed for peak oxygen consumption(VO_(2))with patients as random effect and age,sex,disease classification,preceding surgery(≤3 months)and preceding CR(≤4 weeks for short term and>4 weeks for long term)as fixed effects.Results:1056 CPETs of 311 ACHD patients with simple(7),moderate(188)or great(116)complexity heart defects were analysed.The 59 patients who completed a CR(median age 27 yrs,38%females)increased peak VO_(2)from before to after CR by a median of 2.7(IQR–0.6 to 5.5)ml/kg/min.However,in the multivariate mixed model,peak VO_(2)was non-significantly increased short-term after CR(β0.8,95%CI–0.7 to 2.4),not maintained long-term after CR(β0.0,95%CI–1.7 to 1.6)but significantly reduced after surgery(β–5.1,95%CI–7.1 to–3.1).The 20 CR patients after surgery increased their peak VO_(2)by 6.2(IQR 3.6–9.5)ml/kg/min,while the 39 CR patients without preceding surgery increased it by 0.9(IQR–1.5 to 3.1)ml/kg/min.Conclusions:The increase in peak VO_(2)with CR was mainly due to recovery from surgical intervention.The small independent benefit from CR was not maintained long-term,highlighting the potential to improve current CR concepts in ACHD populations.

Effects of a school-based karate intervention on academic achievement,psychosocial functioning,and physical fitness:A multi-country cluster randomized controlled trial

Purpose:To examine the effects of a school-based karate intervention on academic achievement,psychosocial functioning,and physical fitness in children aged 7-8 years.Methods:Twenty schools in 5 different European countries(2 second-grade classrooms per school)participated in a cluster randomized controlled trial(Sport at School trial).Participants were assigned to either a control group,which continued with their habitual physical education lessons,or to an intervention group,which replaced these lessons with a 1-year karate intervention(Karate Mind and Movement program).A total of 721 children(344 girls and 377 boys,7.4±0.5 years old,mean±SD)completed the study,of which 333 and 388 were assigned to the control group and intervention group,respectively.Outcomes included academic performance(average grade),psychosocial functioning(Strengths and Difficulties Questionnaire for parents),and different markers of physical fitness(cardiorespiratory fitness,balance,and flexibility).Results:The intervention provided small but significant benefits compared to the control group for academic achievement(d=0.16;p=0.003),conduct problems(d=-0.28;p=0.003),cardiorespiratory fitness(d=0.36;p<0.001),and balance(d=0.24;p=0.015).There was a trend towards significant benefits for flexibility(d=0.24;p=0.056).No significant benefits were observed for other variables,including psychosocial difficulties,emotional symptoms,hyperactivity/inattention,peer problems,or prosocial behaviour(all p>0.05).Conclusion:A 1-year school-based karate intervention was effective in improving academic achievement,conduct problems,and physical fitness in primary school children.The results support the inclusion of karate during physical education lessons.

Is BMI Associated with Cardiorespiratory Fitness?A Cross-Sectional Analysis Among 8470 Apparently Healthy Subjects Aged 18-94 Years from the Low-Lands Fitness Registry

Objective The purpose of the present study was to investigate the association between cardiorespiratory fitness(CRF)measured as peak oxygen uptake(VO_(2peak),expressed in mL/min)and body mass index(BMI)in a large cohort of apparently healthy subjects.Methods BMI and VO_(2peak)were measured in a cross-sectional study of 8470 apparently healthy adults.VO_(2peak)(mL/min)was determined by an incremental cycle ergometer test to exhaustion.Linear regression analyses were performed to identify predictors of CRF.Results There was no difference in CRF between adults with a normal weight(BMI between 18.5-24.9 kg/m^(2))and those who were overweight(BMI 25.0-29.9 kg/m^(2)).Subjects who were underweight(BMI<18.5 kg/m^(2))as well as females who were obese(BMI≥30.0 kg/m^(2))showed a reduced CRF compared to the normal and overweight groups.Age,height,and gender were significant predictors of CRF(R^(2)=0.467,P<0.0001);BMI did not add significantly to this relationship.Conclusion Our findings indicate that BMI was not associated with CRF in addition to age,height,and gender.In subjects with a BMI<18.5 kg/m^(2),CRF was lower compared to subjects with a BMI between 18.5 and 29.9 kg/m^(2).In obese subjects,CRF was only lower in females compared to females with a BMI between 18.5 and 29.9 kg/m^(2).Correcting CRF for BMI may be beneficial for subjects with a low BMI,and females with a BMI≥30.0 kg/m^(2).The outcome of this study might help to improve the interpretation of exercise testing results in individuals with a low or high BMI.

Fatigability during volitional walking in incomplete spinal cord injury: cardiorespiratory and motor performance considerations

Fatigability describes the decline in force production（i.e., performance fatigability） and/or changes in sensations regulating performance（i.e., perceived fatigability） during whole-body activity and poses a major challenge to those living with spinal cord injuries（SCI）. After SCI, the inability to overcome disruptions to metabolic homeostasis due to cardiorespiratory limitations and physical deconditioning may contribute to increased fatigability severity. The increased susceptibility to fatigability may have implications for motor control strategies and motor learning. Locomotor training approaches designed to reduce fatigability and enhance aerobic capacity in combination with motor learning may be advantageous for promoting functional recovery after SCI. Future research is required to advance the understanding of the relationship between fatigability, cardiorespiratory function and motor performance following SCI.

Effect of high-intensity interval training in adolescents with asthma:The eXercise for Asthma with Commando Joe’s^(■)(X4ACJ)trial

Background:Higher levels of cardiorespiratory fitness are associated with reduced asthma severity and increased quality of life in those with asthma.Therefore,the purpose of this study was to evaluate the effectiveness of a 6-month high-intensity interval training(HIIT)intervention in adolescents with and without asthma.Methods:A total of 616 adolescents(334 boys;13.0±1.1 years,1.57±0.10 m,52.6±12.9 kg,mean±SD),including 155 with asthma(78 boys),were recruited as part of a randomized controlled trial from 5 schools(4 control and 1 intervention).The 221 intervention participants(116 boys;47 asthma)completed 6 months of school-based HIIT(30 min,3 times per week,10-30 s bouts at>90%age-predicted maximum heart rate with equal rest).At baseline,mid-intervention,post-intervention,and 3-month follow-up,measurements for 20-m shuttle run,body mass index(BMI),lung function,Pediatric Quality of Life Inventory,Paediatric Asthma Quality of Life Questionnaire,and Asthma Control Questionnaire were collected.Additionally,69 adolescents(39 boys(of the 36 with asthma there were 21 boys))also completed an incremental ramp test.For analysis,each group’s data(intervention and control)were divided into those with and without asthma.Results:Participants with asthma did not differ from their peers in any parameter of aerobic fitness,at any time-point,but were characterized by a greater BMI.The intervention elicited a significant improvement in maximal aerobic fitness but no change in sub-maximal parameters of aerobic fitness,lung function,or quality of life irrespective of asthma status.Those in the intervention group maintained their BMI,whereas BMI significantly increased in the control group throughout the 6-month period.Conclusion:HIIT represents an effective tool for improving aerobic fitness and maintaining BMI in adolescents,irrespective of asthma status.HIIT was well-tolerated by those with asthma,who evidenced a similar aerobic fitness to their healthy peers and responded equally well to a HIIT program.

Risk of bias and reporting practices in studies comparing VO2max responses to sprint interval vs.continuous training:A systematic review and meta-analysis

Background:It remains unclear whether studies comparing _(max)imal oxygen uptake(VO_(2max))response to sprint interval training(SIT)vs.moderate-intensity continuous training(MICT)are associated with a high risk of bias and poor reporting quality.The purpose of this study was to evaluate the risk of bias and quality of reporting in studies comparing changes in VO_(2max) between SIT and MICT.Methods:We conducted a comprehensive literature search of 4 major databases:AMED,CINAHL,EMBASE,and MEDLINE.Studies were excluded if participants were not healthy adult humans or if training protocols were unsupervised,lasted less than 2 weeks,or utilized mixed exercise modalities.We used the Cochrane Collaboration tool and the CONSORT checklist for non-pharmacological trials to evaluate the risk of bias and reporting quality,respectively.Results:Twenty-eight studies with 30 comparisons(3 studies included 2 SIT groups)were included in our meta-analysis(n=360 SIT participants:body mass index(BMI)=25.9±3.7 kg/m^(2),baseline VO_(2max)=37.9±8.0 mL/kg/min;n=359 MICT participants:BMI=25.5±3.8 kg/m^(2),baseline VO_(2max)=38.3±8.0 mL/kg/min;all mean±SD).All studies had an unclear risk of bias and poor reporting quality.Conclusion:Although we observed a lack of superiority between SIT and MICT for improving VO_(2max)(weighted Hedge’s g=0.004,95%con-fidence interval(95%CI):-0.08 to 0.07),the overall unclear risk of bias calls the validity of this conclusion into question.Future studies using robust study designs are needed to interrogate the possibility that SIT and MICT result in similar changes in VO_(2max).

The effects of low-volume combined training on health-related physical fitness outcomes in active young adults: A controlled clinical trial

The effects of combined training(CT)on improving general health are well known,however,few studies have investigated the effects of low-volume CT.So,the aim of this study is to investigate the effects of 6 weeks of lowvolume CT on body composition,handgrip strength(HGS),cardiorespiratory fitness(CRF)and affective response(AR)to exercise.Eighteen healthy,active young adult man(meanSD,[20.061.66]years;[22.232.76]kg/m2)performed either a low-volume CT(EG,n?9),or maintained a normal life(CG,n?9).The CT was composed of three resistance exercises followed by a high intensity-interval training(HIIT)on cycle ergometer performed twice a week.The measures of the body composition,HGS,maximal oxygen consumption(V_O2max)and AR to exercise were taken at baseline and after training for analysis.Furthermore,an ANOVA test of repeated measures and t-test paired samples were used with a p0.05.The results showed that EG improved HGS(pre:[45.6711.84]kg vs.post:[52.4411.90]kg,p<0.01)and V_O2max(pre:[41.365.16]ml⋅kg-1⋅min-1 vs.post:[44.075.98]ml⋅kg-1⋅min-1,p<0.01).Although,for all measures the body composition had not significant differences between weeks(p>0.05),nevertheless the feeling scale was positive in all weeks and without significant differences between them(p>0.05).Lastly,for active young adults,the low-volume CT improved HGS,CRF and had a positive outcome in AR,with less volume and time spent than traditional exercise recommendations.

Cardiac Autonomic Control in Relation to Other Prognostic Markers in Idiopathic Dilated Cardiomyopathy

Objectives: We set out to study cardiac autonomic tone in patients with idiopathic dilated cardio-myopathy (IDC), and whether it correlates with other established markers of disease progression and patient ultimate outcome. Design: Fifty-one IDC patients in sinus rhythm underwent extensive non-invasive and invasive evaluation during a three-day hospitalization period. The control group consisted of thirty-eight apparently healthy subjects who underwent 24-hour ambulatory ECG recording. Results: Heart rate variability (HRV) and heart rate turbulence (HRT) correlated with many previously established prognostic markers of IDC and congestive heart failure, especially measures of cardiorespiratory performance capacity and circulating neurohumoral factors (p < 0.05 for all). Furthermore, attenuated HRV correlated with worse prognosis during a median follow-up of 6.8 years (range 5.1 - 8.1). Additionally, 24-hour time domain, low and high frequency components of frequency domain and non-linear HRV, excluding scaling exponents (α), were lower in IDC patients as compared with controls (p < 0.05 for all);however, HRT was not significantly different. Conclusions: The magnitude of impairment in cardiac autonomic control correlates well with other prognostic markers of IDC, and is associated with unfavorable outcome.

Development,validation,and transportability of several machine-learned,non-exercise-based VO_(2max)prediction models for older adults

Background:There exist few maximal oxygen uptake(VO_(2max))non-exercise-based prediction equations,fewer using machine learning(ML),and none specifically for older adults.Since direct measurement of VO_(2max)is infeasible in large epidemiologic cohort studies,we sought to develop,validate,compare,and assess the transportability of several ML VO_(2max)prediction algorithms.Methods:The Baltimore Longitudinal Study of Aging(BLSA)participants with valid VO2_(max)tests were included(n=1080).Least absolute shrinkage and selection operator,linear-and tree-boosted extreme gradient boosting,random forest,and support vector machine(SVM)algorithms were trained to predict VO_(2max)values.We developed these algorithms for:(a)the overall BLSA,(b)by sex,(c)using all BLSA variables,and(d)variables common in aging cohorts.Finally,we quantified the associations between measured and predicted VO_(2max)and mortality.Results:The age was 69.0±10.4 years(mean±SD)and the measured VO_(2max)was 21.6±5.9 mL/kg/min.Least absolute shrinkage and selection operator,linear-and tree-boosted extreme gradient boosting,random forest,and support vector machine yielded root mean squared errors of 3.4 mL/kg/min,3.6 mL/kg/min,3.4 mL/kg/min,3.6 mL/kg/min,and 3.5 mL/kg/min,respectively.Incremental quartiles of measured VO_(2max)showed an inverse gradient in mortality risk.Predicted VO_(2max)variables yielded similar effect estimates but were not robust to adjustment.Conclusion:Measured VO_(2max)is a strong predictor of mortality.Using ML can improve the accuracy of prediction as compared to simpler approaches but estimates of association with mortality remain sensitive to adjustment.Future studies should seek to reproduce these results so that VO_(2max),an important vital sign,can be more broadly studied as a modifiable target for promoting functional resiliency and healthy aging.

Association between baseline levels of muscular strength and risk of stroke in later life:The Cooper Center Longitudinal Study

Background:Muscular strength is an important component of physical fitness.We evaluated the relationship between baseline muscular strength and risk of stroke among adults who were aged≥65 years during follow-up.Methods:We included 7627 healthy adults(mean age=43.9 years,86.0%male)underwent a baseline physical examination between 1980 and 1989.Muscular strength was determined by 1-repetition maximum measures for bench press and leg press and categorized into age-and sex-specific tertiles for each measure.Cardiorespiratory fitness(CRF)was assessed via a maximal treadmill exercise test.Those enrolled in fee-for-service Medicare from 1999 to 2019 were included in the analyses.Associations between baseline strength and stroke outcomes were estimated using a modified Cox proportional hazards model.In a secondary analysis,we examined stroke risk by categories of CRF where Quintile 1=low,Quintiles 2-3=moderate,and Quintiles 4-5=high CRF based on age and sex.Results:After 70,072 person-years of Medicare follow-up,there were 1211 earliest indications of incident stroke.In multivariable analyses,the hazard ratio(95%confidence interval(95%CI))for stroke across bench press categories were 1.0(referent),0.96(0.83-1.11),and 0.89(0.77-1.04),respectively(p trend=0.14).The trend across categories of leg press was also non-significant(p trend=0.79).Adjusted hazard ratio(95%CI)for stroke across ordered CRF categories were 1.0(referent),0.90(0.71-1.13),and 0.72(0.57-0.92)(p trend<0.01).Conclusion:While meeting public health guidelines for muscular strengthening activities is likely to improve muscular strength as well as many health outcomes in older adults,performing such activities may not be helpful in preventing stroke.Conversely,meeting guidelines for aerobic activity is likely to improve CRF and lower stroke risk.

Habitual sedentary time and stationary time are inversely related to aerobic fitness

A one metabolic-equivalent-of-task increase in peak aerobic fitness(peak MET)is associated with a clinically relevant improvement in survival risk and all-cause mortality.The co-dependent impact of free-living physical behaviours on aerobic fitness are poorly understood.The purpose of this study was to investigate the impact of theoretically re-allocating time spent in physical behaviours on aerobic fitness.We hypothesized that substituting sedentary time with any physical activity(at any intensity)would be associated with a predicted improvement in aerobic fitness.Peak volume rate of oxygen uptake(VO_(2)peak)was assessed via indirect calorimetry during a progressive,maximal cycle ergometer protocol in 103 adults(52 females;[38±21]years;[25.0±3.8]kg/m^(2);VO_(2)peak:[35.4±11.5]ml⋅kg^(-1)⋅min^(-1)).Habitual sedentary time,standing time,light-(LPA),moderate-(MPA),and vigorous-physical activity(VPA)were assessed 24-h/day via thigh-worn inclinometry for up to one week(average:[6.3±0.9]days).Isotemporal substitution modelling examined the impact of replacing one physical behaviour with another.Sedentary time(β=0.8,95%CI:[-1.3,-0.2])and standing time(β=0.9,95%CI:[-1.6,-0.2])were negatively associated with VO_(2)peak,whereas VPA was positively associated with relative VO_(2)peak(β=9.2,95%CI:[0.9,17.6]).Substituting 30-min/day of VPA with any other behaviour was associated with a 2.4–3.4 higher peak MET.Higher standing time was associated with a lower aerobic fitness.As little as 10-min/day of VPA predicted a clinically relevant 0.8–1.1 peak MET increase.Theoretically,replacing any time with relatively small amounts of VPA is associated with improvements in aerobic fitness.

Effect of exercise on inhibitory control is dose-dependent for adolescents

Adolescence is an important stage for brain maturation.To investigate the effect of different exercise doses on inhibitory control in adolescents aged 12 to 14-year old,an after-school exercise program was offered 5 days per week for 12 weeks during a school semester.Thirsty-four adolescents(17 boys)from the first six classes were randomly divided into low-dose exercise group(LE group,one 30-min aerobic exercise bout per day,n=16)and high-dose exercise group(HE group,two 30-min aerobic exercise bouts per day,n=18),while 23 adolescents(10 boys)in the control group(CON,zero 30-min exercise bout,n=23)were from the last two classes.All the participants in different classes received the same physical education with the same contents,duration,and intensity at class.All the participants completed flanker tests and cardiorespiratory tests before and after exercise intervention.The HE group showed more significant improvements on inhibitory control and VO_(2peak)than CON(p<0.05).Changes in physical activity(PA)were significantly correlated with changes in interference scores(Spearman rho=-0.30,p<0.05),VO_(2peak)(Spearman rho=0.31,p<0.05),and BF percentage(Spearman rho=-0.32,p<0.05).This study demonstrated that effect of exercise on inhibitory control in adolescents is dose-dependent,which highlights the need to focus on the exercise dose in daily life for improving cognition among adolescents.