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.

Effects of exercise training on diastolic and systolic dysfunction in patients with chronic heart failure

BACKGROUND Chronic heart failure(CHF)is a complex syndrome characterized by a progressive reduction of the left ventricular(LV)contractility,low exercise tolerance,and increased mortality and morbidity.Diastolic dysfunction(DD)of the LV,is a keystone in the pathophysiology of CHF and plays a major role in the progression of most cardiac diseases.Also,it is well estimated that exercise training induces several beneficial effects on patients with CHF.AIM To evaluate the impact of a cardiac rehabilitation program on the DD and LV ejection fraction(EF)in patients with CHF.METHODS Thirty-two stable patients with CHF(age:56±10 years,EF:32%±8%,88%men)participated in an exercise rehabilitation program.They were randomly assigned to aerobic exercise(AER)or combined aerobic and strength training(COM),based on age and peak oxygen uptake,as stratified randomization criteria.Before and after the program,they underwent a symptom-limited maximal cardiopulmonary exercise testing(CPET)and serial echocardiography evaluation to evaluate peak oxygen uptake(VO2peak),peak workload(Wpeak),DD grade,right ventricular systolic pressure(RVSP),and EF.RESULTS The whole cohort improved VO2peak,and Wpeak,as well as DD grade(P<0.05).Overall,9 patients(28.1%)improved DD grade,while 23(71.9%)remained at the same DD grade;this was a significant difference,considering DD grade at baseline(P<0.05).In addition,the whole cohort improved RVSP and EF(P<0.05).Not any between-group differences were observed in the variables assessed(P>0.05).CONCLUSION Exercise rehabilitation improves indices of diastolic and systolic dysfunction.Exercise protocol was not observed to affect outcomes.These results need to be further investigated in larger samples.