High intensity interval exercise training in overweight young women. Continuous Exercise but Not High Intensity Interval Training Improves Fat Distribution in Overweight Adults One year of high-intensity interval training improves exercise capacity, but not left ventricular function in stable heart transplant recipients: A randomised controlled trial The effect of three different exercise training modalities on cognitive and physical function in a healthy older population High-Intensity Interval Training in Patients With Heart Failure With Reduced Ejection Fraction Fatigue Exacerbation by Interval or Continuous Exercise in Chronic Fatigue Syndrome. Acute effects of interval versus continuous endurance training on pulse wave reflection in healthy young men. High-Intensity Interval Training and Isocaloric Moderate-Intensity Continuous Training Result in Similar Improvements in Body Composition and Fitness in Obese Individuals. High-intensity interval training versus moderate-intensity steady-state training in UK cardiac rehabilitation programmes (HIIT or MISS UK): study protocol for a multicentre randomised controlled trial and economic evaluation Effects of High-Intensity Intermittent Exercise Training on Appetite Regulation. The Effects of High Intensity Interval Training vs Steady State Training on Aerobic and Anaerobic Capacity. Novel all-extremity high-intensity interval training improves aerobic fitness, cardiac function and insulin resistance in healthy older adults Usefulness of the 6-minute walk test and the 200-metre fast walk test to individualize high intensity interval and continuous exercise training in coronary artery disease patients after acute coronary syndrome: a pilot controlled clinical study High-Intensity Interval Training as an Efficacious Alternative to Moderate-Intensity Continuous Training for Adults with Prediabetes Effect of High‐Intensity Training Versus Moderate Training on Peak Oxygen Uptake and Chronotropic Response in Heart Transplant Recipients: A Randomized Crossover Trial Effects of different aerobic exercise programmes with nutritional intervention in sedentary adults with overweight/obesity and hypertension: EXERDIET-HTA study Interval versus Continuous High-Intensity Exercise in Chronic Obstructive Pulmonary Disease
AIM The purpose of this study was intended to evaluate the effects of a high intensity interval training ( HIIT ) program on the body composition , cardiac function and aerobic capacity in overweight young women . METHODS Sixty female university students ( aged 19 - 20 , BMI ≥25kg/m2 and percentage body fat ≥ 30 % ) were chosen and then r and omly assigned to each of the HIIT group , the moderate intensity continuous training ( MICT ) group and the non-training control group . The subjects in both the HIIT and MICT groups underwent exercise training five times per week for 12 weeks . In each of the training sessions , the HIIT group performed interval exercises at the individualized heart rate ( HR ) of 85 % of VO2max and separated by brief periods of low intensity activity ( HR at 50 % of VO2max ) , while the MICT group did continuous walking and /or jogging at the individualized HR of 50 % of VO2max . RESULTS Both of these exercise training programs produced significant improvements in the subjects ' body composition , left ventricular ejection fraction , heart rate at rest , maximal oxygen uptake and ventilatory threshold . However , the HIIT group achieved better results than those in the MICT group , as it was evaluated by the amount of the effect size . The control group did not achieve any change in all of the measured variables . CONCLUSION The tangible results achieved by our relatively large groups of homogeneous subjects have demonstrated that the HIIT program is an effective measure for the treatment of young women who are overweight Objective . The purpose of this study was to assess the effect of high intensity interval training ( HIIT ) versus continuous aerobic exercise training ( CONT ) or placebo ( PLA ) on body composition by r and omized controlled design . Methods . Work capacity and body composition ( dual-energy X-ray absorptiometry ) were measured before and after 12 weeks of intervention in 38 previously inactive overweight adults . Results . There was a significant group × time interaction for change in work capacity ( P < 0.001 ) , which increased significantly in CONT ( 23.8 ± 3.0 % ) and HIIT ( 22.3 ± 3.5 % ) but not PLA ( 3.1 ± 5.0 % ) . There was a near-significant main effect for percentage trunk fat , with trunk fat reducing in CONT by 3.1 ± 1.6 % and in PLA by 1.1 ± 0.4 % , but not in HIIT ( increase of 0.7 ± 1.0 % ) ( P = 0.07 ) . There was a significant reduction in and roid fat percentage in CONT ( 2.7 ± 1.3 % ) and PLA ( 1.4 ± 0.8 % ) but not HIIT ( increase of 0.8 ± 0.7 % ) ( P = 0.04 ) . Conclusion . These data suggest that HIIT may be advocated as a time-efficient strategy for eliciting comparable fitness benefits to traditional continuous exercise in inactive , overweight adults . However , in this population HIIT does not confer the same benefit to body fat levels as continuous exercise training Background Heart transplant recipients have lower exercise capacity and impaired cardiac function compared with the normal population . High-intensity interval training ( HIIT ) improves exercise capacity and cardiac function in patients with heart failure and hypertension , but the effect on cardiac function in stable heart transplant recipients is not known . Thus , we investigated whether HIIT improved cardiac function and exercise capacity in stable heart transplant recipients by use of comprehensive rest- and exercise-echocardiography and cardiopulmonary exercise testing . Design and methods Fifty-two clinical ly stable heart transplant recipients were r and omised either to HIIT ( 4 × 4 minutes at 85–95 % of peak heart rate three times per week for eight weeks ) or to control . Three such eight-week periods were distributed throughout one year . Echocardiography ( rest and submaximal exercise ) and cardiopulmonary exercise testing were performed at baseline and follow-up . Results One year of HIIT  increased VO2peak from 27.7 ± 5.5 at baseline to 30.9 ± 5.0 ml/kg/min at follow-up , while the control group remained unchanged ( 28.5 ± 7.0 vs. 28.0 ± 6.7 ml/kg per min , p < 0.001 for difference between the groups ) . Systolic and diastolic left ventricular functions at rest and during exercise were generally unchanged by HIIT . Conclusions Whereas HIIT is feasible in heart transplant recipients and effectively improves exercise capacity , it does not alter cardiac systolic and diastolic function significantly . Thus , the observed augmentation in exercise capacity is best explained by extra-cardiac adaptive mechanisms Background Older adults are encouraged to participate in regular physical activity to counter the age-related declines in physical and cognitive health . Literature on the effect of different exercise training modalities ( aerobic vs resistance ) on these health-related outcomes is not only sparse , but results are inconsistent . In general , it is believed that exercise has a positive effect on executive cognitive function , possibly because of the physiological adaptations through increases in fitness . Indications are that high-intensity interval training is a potent stimulus to improve cardiovascular fitness , even in older adults ; however , its effect on cognitive function has not been studied before . Therefore , the purpose of this study was to compare the effects of resistance training , high-intensity aerobic interval training and moderate continuous aerobic training on the cognitive and physical functioning of healthy older adults . Methods Sixty-seven inactive individuals ( 55 to 75 years ) were r and omly assigned to a resistance training ( RT ) group ( n = 22 ) , high-intensity aerobic interval training ( HIIT ) group ( n = 13 ) , moderate continuous aerobic training ( MCT ) group ( n = 13 ) and a control ( CON ) group ( n = 19 ) for a period of 16 weeks . Cognitive function was assessed with a Stroop task and physical function with the Timed-Up- and -Go ( TUG ) and submaximal Bruce treadmill tests . Results No significant GROUP x TIME interaction was found for Stroop reaction time ( P > .05 ) . The HIIT group showed the greatest practical significant improvement in reaction time on the information processing task , i.e. Stroop Neutral ( ES = 1.11 ) . MCT group participants had very large practical significant improvements in reaction time on the executive cognitive tasks , i.e. Stroop Incongruent and Interference ( ES = 1.28 and 1.31 , respectively ) . The HIIT group showed the largest practically significant increase in measures of physical function , i.e. walking endurance ( ES = 0.91 ) and functional mobility ( ES = 0.36 ) . Conclusions MCT and RT proved to be superior to HIIT for the enhancement of older individuals ’ executive cognitive function ; whereas HIIT were most beneficial for improvement in information processing speed . HIIT also induced the largest gains in physical function Background : Small studies have suggested that high-intensity interval training ( HIIT ) is superior to moderate continuous training ( MCT ) in reversing cardiac remodeling and increasing aerobic capacity in patients with heart failure with reduced ejection fraction . The present multicenter trial compared 12 weeks of supervised interventions of HIIT , MCT , or a recommendation of regular exercise ( RRE ) . Methods : Two hundred sixty-one patients with left ventricular ejection fraction ⩽35 % and New York Heart Association class II to III were r and omly assigned to HIIT at 90 % to 95 % of maximal heart rate , MCT at 60 % to 70 % of maximal heart rate , or RRE . Thereafter , patients were encouraged to continue exercising on their own . Clinical assessment s were performed at baseline , after the intervention , and at follow-up after 52 weeks . Primary end point was a between-group comparison of change in left ventricular end-diastolic diameter from baseline to 12 weeks . Results : Groups did not differ in age ( median , 60 years ) , sex ( 19 % women ) , ischemic pathogenesis ( 59 % ) , or medication . Change in left ventricular end-diastolic diameter from baseline to 12 weeks was not different between HIIT and MCT ( P=0.45 ) ; left ventricular end-diastolic diameter changes compared with RRE were −2.8 mm ( −5.2 to −0.4 mm ; P=0.02 ) in HIIT and −1.2 mm ( −3.6 to 1.2 mm ; P=0.34 ) in MCT . There was also no difference between HIIT and MCT in peak oxygen uptake ( P=0.70 ) , but both were superior to RRE . However , none of these changes was maintained at follow-up after 52 weeks . Serious adverse events were not statistically different during supervised intervention or at follow-up at 52 weeks ( HIIT , 39 % ; MCT , 25 % ; RRE , 34 % ; P=0.16 ) . Training records showed that 51 % of patients exercised below prescribed target during supervised HIIT and 80 % above target in MCT . Conclusions : HIIT was not superior to MCT in changing left ventricular remodeling or aerobic capacity , and its feasibility remains unresolved in patients with heart failure . Clinical Trial Registration : URL : http://www . clinical trials.gov . Unique identifier : NCT00917046 PURPOSE The objective of this study is to determine whether the typical exacerbation of symptoms in patients with chronic fatigue syndrome ( CFS ) after a bout of exercise differs between high-intensity interval training ( HIIT ) or continuous ( CONT ) aerobic exercise of the same duration and mechanical work . METHODS Participants with specialist-diagnosed CFS performed two 20-min bouts of cycling in a r and omized crossover study . The bouts were either moderate-intensity continuous ( 70 % age-predicted HR maximum ) or high-intensity interval exercise , separated by at least 2 wk . Self-report question naires capturing fatigue , the related symptoms , and actigraphy were collected across 2 d before and 4 d after the exercise . Comparisons between exercise bouts were made using paired sample t-tests . RESULTS Fourteen moderately affected participants who were unable to work , but not bed bound , completed the study ( nine female , 32 ± 10 yr , 67 ± 11 kg ) . Mechanical work was matched successfully between the exercise bouts ( HIIT , 83,037 , vs CONT , 83,348 J , P = 0.84 ) . Mean HR ( HIIT , 76 % ± 5 % , vs CONT , 73 % ± 6 % age-predicted HR maximum , P < 0.05 ) and RPE ( 6 - 20 ) in the legs ( HIIT , 15.4 ± 1.4 , vs CONT , 13.2 ± 1.2 , P < 0.001 ) were higher for the interval compared with continuous exercise . Mean fatigue scores ( 0 - 10 ) were similar before each exercise challenge ( HIIT , 4.5 ± 1.8 , vs CONT , 4.1 ± 1.7 , P = 0.43 ) . Participants reported an increase in fatigue scores after both challenges ( mean difference : HIIT , 1.0 ± 1.3 , P < 0.01 ; CONT , 1.5 ± 0.7 , P < 0.001 ) , but these exacerbations in fatigue were not statistically or clinical ly different ( P = 0.20 ) . CONCLUSIONS High-intensity interval exercise did not exacerbate fatigue any more than continuous exercise of comparable workload . This finding supports evaluation of HIIT in grade d exercise therapy interventions for patients with CFS AIM Our aim was to investigate the acute and 24-hour ( h ) effects of high-intensity interval training ( HIIT ) and moderate continuous training ( MCT ) on arterial pulse wave reflection , an established marker of arterial stiffness and cardiovascular risk . METHODS In a r and omized cross-over design , 21 young healthy male participants performed a HIIT or a MCT on separate visits . Before and 5 ( t5 ) , 20 ( t20 ) , 35 ( t35 ) , and 50 ( t50 ) minutes after the acute exercise bouts , the crude augmentation index ( AIx ) and the AIx at a set heart rate ( AIx@75 ) were analysed by applanation tonometry . Starting 1 h post-exercise , both indices were captured over 24-h with an oscillometric monitoring device . RESULTS AIx did not change significantly after MCT but declined progressively after HIIT , reaching significantly lower values compared to MCT at t35 ( P = 0.045 ) and t50 ( P = 0.008 ) . AIx@75 increased after both acute exercise types but was higher after HIIT at t5 ( P < 0.001 ) , t20 ( P < 0.001 ) and t35 ( P = 0.009 ) compared to MCT . The 24-h follow-up revealed a significant decline in AIx@75 after HIIT ( P = 0.007 ) but not after MCT ( P = 0.813 ) . CONCLUSIONS Exercise intensity affects pulse wave reflection , with different time courses for AIx and AIx@75 post-exercise . Although initially higher after HIIT , AIx@75 declines in the 24-h recovery period indicating more favourable effects on pulse wave reflection compared to MCT . This may result in substantial positive chronic training effects on arterial stiffness in health and cardiovascular disease This study aim ed to determine the effects of 12 weeks of isocaloric programs of high-intensity intermittent training ( HIIT ) or moderate-intensity continuous training ( MICT ) or a short- duration HIIT ( 1/2HIIT ) inducing only half the energy deficit on a cycle ergometer , on body weight and composition , cardiovascular fitness , resting metabolism rate ( RMR ) , respiratory exchange ratio ( RER ) , nonexercise physical activity ( PA ) levels and fasting and postpr and ial insulin response in sedentary obese individuals . Forty-six sedentary obese individuals ( 30 women ) , with a mean BMI of 33.3 ± 2.9 kg/m2 and a mean age of 34.4 ± 8.8 years were r and omly assigned to one of the three training groups : HIIT ( n = 16 ) , MICT ( n = 14 ) or 1/2HIIT ( n = 16 ) and exercise was performed 3 times/week for 12 weeks . Overall , there was a significant reduction in body weight , waist ( p < .001 ) and hip ( p < .01 ) circumference , , trunk and leg fat mass ( FM ; p < .01 ) and an increase in trunk and leg fat free mass ( FFM ; p < .01 ) and cardiovascular fitness ( VO2max in ml/kg/min ; p < .001 ) with exercise . However , no significant differences were observed between groups . There was no significant change in RMR , RER , nonexercise PA levels , fasting insulin or insulin sensitivity with exercise or between groups . There was a tendency for a reduction in AUC insulin with exercise ( p = .069 ) , but no differences between groups . These results indicate that isocaloric training protocol s of HIIT or MICT ( or 1/2HIIT inducing only half the energy deficit ) exert similar metabolic and cardiovascular improvements in sedentary obese individuals Introduction Current international guidelines for cardiac rehabilitation ( CR ) advocate moderate-intensity exercise training ( MISS , moderate-intensity steady state ) . This recommendation pre date s significant advances in medical therapy for coronary heart disease ( CHD ) and may not be the most appropriate strategy for the ‘ modern ’ patient with CHD .  High-intensity interval training ( HIIT ) appears to be a safe and effective alternative , result ing in greater improvements in peak oxygen uptake ( VO2 peak ) . To date , HIIT trials have predominantly been proof-of-concept studies in the laboratory setting and conducted outside the UK . The purpose of this multicentre r and omised controlled trial is to compare the effects of HIIT and MISS training in patients with CHD attending UK CR programmes . Methods and analysis This pragmatic study will r and omly allocate 510 patients with CHD to 8 weeks of twice weekly HIIT or MISS training at 3 centres in the UK .  HIIT will consist of 10 high-intensity ( 85–90 % peak power output ( PPO ) ) and 10 low-intensity ( 20–25 % PPO ) intervals , each lasting 1 min . MISS training will follow usual care recommendations , adhering to currently accepted UK guidelines ( ie , > 20 min continuous exercise at 40–70 % heart rate reserve ) . Outcome measures will be assessed at baseline , 8 weeks and 12 months . The primary outcome for the trial will be change in VO2 peak as determined by maximal cardiopulmonary exercise testing . Secondary measures will assess physiological , psychosocial and economic outcomes . Ethics and dissemination The study protocol V.1.0 , date d 1 February 2016 , was approved by the NHS Health Research Authority , East Midl and s — Leicester South Research Ethics Committee ( 16/EM/0079 ) . Recruitment will start in August 2016 and will be completed in June 2018 . Results will be published in peer- review ed journals , presented at national and international scientific meetings and are expected to inform future national guidelines for exercise training in UK CR . Trial registration number NCT02784873 ; pre- results OBJECTIVE An acute bout of high-intensity intermittent exercise suppresses ad libitum energy intake at the postexercise meal . The present study examined the effects of 12 wk of high-intensity intermittent exercise training ( HIIT ) compared with moderate-intensity continuous exercise training ( MICT ) on appetite regulation . METHODS Thirty overweight inactive men ( body mass index , 27.2 ± 1.3 kg·m(-2 ) ; V˙O2peak , 35.3 ± 5.3 mL·kg(-1)·min(-1 ) were r and omized to either HIIT or MICT  ( involving 12 wk of training , three sessions per week ) or a control group ( CON ) ( n = 10 per group ) . Ad libitum energy intake from a laboratory test meal was assessed after both a low-energy ( 847 kJ ) and a high-energy preload ( 2438 kJ ) before and  after the intervention . Perceived appetite and appetite-related blood variables were also measured . RESULTS There was no significant effect of the intervention period on energy intake at the test meal after the two different preloads ( P ≥ 0.05 ) . However , the 95 % confidence interval indicated a clinical ly meaningful decrease in energy intake after the high-energy preload compared with the low-energy preload in response to HIIT ( 516 ± 395 kJ decrease ) , but not for MICT or CON , suggesting improved appetite regulation . This was not associated with alterations in the perception of appetite or the circulating concentration of a number of appetite-related peptides or metabolites , although insulin sensitivity was enhanced with HIIT only ( P = 0.003 ) . CONCLUSIONS HIIT seems to benefit appetite regulation in overweight men . The mechanisms for this remain to be eluci date UNLABELLED High intensity interval training ( HIIT ) has become an increasingly popular form of exercise due to its potentially large effects on exercise capacity and small time requirement . This study compared the effects of two HIIT protocol s vs steady-state training on aerobic and anaerobic capacity following 8-weeks of training . Fifty-five untrained college-aged subjects were r and omly assigned to three training groups ( 3x weekly ) . Steady-state ( n = 19 ) exercised ( cycle ergometer ) 20 minutes at 90 % of ventilatory threshold ( VT ) . Tabata ( n = 21 ) completed eight intervals of 20s at 170 % VO2max/10s rest . Meyer ( n = 15 ) completed 13 sets of 30s ( 20 min ) @ 100 % PVO2 max/ 60s recovery , average PO = 90 % VT . Each subject did 24 training sessions during 8 weeks . RESULTS There were significant ( p < 0.05 ) increases in VO2max ( + 19 , + 18 and + 18 % ) and PPO ( + 17 , + 24 and + 14 % ) for each training group , as well as significant increases in peak ( + 8 , + 9 and + 5 % ) & mean ( + 4 , + 7 and + 6 % ) power during Wingate testing , but no significant differences between groups . Measures of the enjoyment of the training program indicated that the Tabata protocol was significantly less enjoyable ( p < 0.05 ) than the steady state and Meyer protocol s , and that the enjoyment of all protocol s declined ( p < 0.05 ) across the duration of the study . The results suggest that although HIIT protocol s are time efficient , they are not superior to conventional exercise training in sedentary young adults . Key pointsSteady state training equivalent to HIIT in untrained studentsMild interval training presents very similar physiologic challenge compared to steady state trainingHIIT ( particularly very high intensity variants were less enjoyable than steady state or mild interval trainingEnjoyment of training decreases across the course of an 8 week experimental training program Aging is associated with decreased aerobic fitness and cardiac remodeling leading to increased risk for cardiovascular disease . High-intensity interval training ( HIIT ) on the treadmill has been reported to be more effective in ameliorating these risk factors compared with moderate-intensity continuous training ( MICT ) in patients with cardiometabolic disease . In older adults , however , weight-bearing activities are frequently limited due to musculoskeletal and balance problems . The purpose of this study was to examine the feasibility and safety of non-weight-bearing all-extremity HIIT in older adults . In addition , we tested the hypothesis that all-extremity HIIT will be more effective in improving aerobic fitness , cardiac function , and metabolic risk factors compared with all-extremity MICT .  Fifty-one healthy sedentary older adults ( age : 65±1years ) were r and omized to HIIT ( n=17 ) , MICT ( n=18 ) or non-exercise control ( CONT ; n=16 ) . HIIT ( 4 × 4min 90 % of peak heart rate ; HRpeak ) and isocaloric MICT ( 70 % of HRpeak ) were performed on a non-weight-bearing all-extremity ergometer , 4 × /week for 8weeks under supervision . All-extremity HIIT was feasible in older adults and result ed in no adverse events . Aerobic fitness ( peak oxygen consumption ; VO2peak ) and ejection fraction ( echocardiography ) improved by 11 % ( P<0.0001 ) and 4 % ( P=0.001 ) , respectively in HIIT , while no changes were observed in MICT and CONT ( P≥0.1 ) . Greater improvements in ejection fraction were associated with greater improvements in VO2peak ( r=0.57 ; P<0.0001 ) . Insulin resistance ( homeostatic model assessment ) decreased only in HIIT by 26 % ( P=0.016 ) . Diastolic function , body composition , glucose and lipids were unaffected ( P≥0.1 ) . In conclusion , all-extremity HIIT  is feasible and safe  in older  adults  . HIIT , but not MICT  , improved aerobic fitness , ejection fraction , and insulin resistance Objective : To study the effects of three individualized exercise training prescriptions using either a percentage of maximal heart rate ( HR ) , maximal 6-minute walk test ( 6MWT ) HR , or maximal 200-metre fast walk test ( 200-mFWT ) HR , on walking performance and exercise capacity in coronary artery disease ( CAD ) patients . Design : Controlled clinical study . Participants : Twenty-seven out patients enrolled in a rehabilitation programme after an acute coronary syndrome . Setting : Cardiac rehabilitation unit . Interventions : Three groups : ( A ) : moderate intensity continuous exercise ( MICE ) at 70 % of the maximal HR of the grade d maximal exercise test ( n = 10 ) ; ( B ) : MICE at the maximal 6MWT HR ( n = 8) ; ( C ) : high intensity interval training ( HIIT ) based on the 6MWT and the 200-mFWT maximal HR ( n = 9 ) . Group B and C performed walk tests every 2 weeks , to readjust training HR ( THR ) if needed . Measures : 6MWT and 200-mFWT performances , peak VO2 and peak power ( Pmax ) . Results : 6MWT and 200-mFWT performances improved significantly and similarly in all groups ( P < 0.05 ) . Peak VO2 improved significantly in all groups ( P < 0.05 ) , this improvement being higher in group C ( HIIT ) versus A ( P < 0.05 ) . Group B was closer to the recommended THR during exercise sessions compared to group A. Conclusion : This pilot study showed that using the 6MWT and 200-mFWT HR to individualize MICE or HIIT prescription is feasible in CAD patients , and could lead them closer to THR objective , to similar improvements in walking performance , and greater peak VO2 increase for HIIT . Future r and omised studies should investigate long-term effects of programmes prescribed from walk tests HR , especially for HIIT modality Aims . High-intensity interval training ( HIIT ) leads to improvements in various markers of cardiometabolic health but adherence to HIIT following a supervised laboratory intervention has yet to be tested . We compared self-report and objective measures of physical activity after one month of independent exercise in individuals with prediabetes who were r and omized to HIIT ( n = 15 ) or traditional moderate-intensity continuous training ( MICT , n = 17 ) . Method . After completing 10 sessions of supervised training  participants were asked to perform HIIT or MICT three times per week for four weeks . Results . Individuals in HIIT ( 89 ± 11 % ) adhered to their prescribed protocol to a greater extent than individuals in MICT ( 71 ± 31 % ) as determined by training logs completed over one-month follow-up ( P = 0.05 , Cohen 's d = 0.75 ) . Minutes spent in vigorous physical activity per week measured by accelerometer were higher in HIIT ( 24 ± 18 ) as compared to MICT ( 11 ± 10 ) at one-month follow-up ( P = 0.049 , Cohen 's d = 0.92 ) . Cardiorespiratory fitness and systolic blood pressure assessed at one-month follow-up were equally improved ( P 's < 0.05 ) . Conclusions . This study provides preliminary evidence that individuals with prediabetes can adhere to HIIT over the short-term and do so at a level that is greater than MICT In heart transplant ( HTx ) recipients , there has been reluctance to recommend high‐intensity interval training ( HIIT ) due to denervation and chronotropic impairment of the heart . We compared the effects of 12 weeks ' HIIT versus continued moderate exercise ( CON ) on exercise capacity and chronotropic response in stable HTx recipients > 12 months after transplantation in a r and omized crossover trial . The study was completed by 16 HTx recipients ( mean age 52 years , 75 % males )  . Baseline peak oxygen uptake ( VO2peak ) was 22.9 mL/kg/min . HIIT increased VO2peak by 4.9 ± 2.7 mL/min/kg ( 17 % ) and CON by 2.6 ± 2.2 mL/kg/min ( 10 % ) ( significantly higher in HIIT ; p < 0.001 ) . During HIIT , systolic blood pressure decreased significantly ( p = 0.037 ) with no significant change in CON ( p = 0.241 ; between group difference p = 0.027 ) . Peak heart rate ( HRpeak ) increased significantly by 4.3 beats per minute ( p = 0.014 ) after HIIT with no significant change in CON ( p = 0.34 ; between group difference p = 0.027 ) . Heart rate recovery ( HRrecovery ) improved in both groups with a trend toward greater improvement after HIIT . The 5‐month washout showed a significant loss of improvement . HIIT was well tolerated , had a superior effect on oxygen uptake , and led to an unexpected increase in HRpeak accompanied by a faster HRrecovery . This indicates that the benefits of HIIT are partly a result of improved chronotropic response Background Both exercise training and diet are recommended to prevent and control hypertension and overweight/obesity . Purpose The purpose of this study was to determine the effectiveness of different 16-week aerobic exercise programmes with hypocaloric diet on blood pressure , body composition , cardiorespiratory fitness and pharmacological treatment . Methods Overweight/obese , sedentary participants ( n = 175 , aged 54.0 ± 8.2 years ) with hypertension were r and omly assigned into an attention control group ( physical activity recommendations ) or one of three supervised exercise groups ( 2 days/week : high-volume with 45 minutes of moderate-intensity continuous training ( MICT ) , high-volume and high-intensity interval training ( HIIT ) , alternating high and moderate intensities , and low-volume HIIT ( 20 minutes ) ) . All variables were assessed pre- and post-intervention . All participants received the same hypocaloric diet . Results Following the intervention , there was a significant reduction in blood pressure and body mass in all groups with no between-group differences for blood pressure . However , body mass was significantly less reduced in the attention control group compared with all exercise groups ( attention control –6.6 % , high-volume MICT –8.3 % , high-volume HIIT –9.7 % , low-volume HIIT –6.9 % ) . HIIT groups had significantly higher cardiorespiratory fitness than high-volume MICT , but there were no significant between-HIIT differences ( attention control 16.4 % , high-volume MICT 23.6 % , high-volume HIIT 36.7 % , low-volume HIIT 30.5 % ) . Medication was removed in 7.6 % and reduced in 37.7 % of the participants . Conclusions The combination of hypocaloric diet with supervised aerobic exercise 2 days/week offers an optimal non-pharmacological tool in the management of blood pressure , cardiorespiratory fitness and body composition in overweight/obese and sedentary individuals with hypertension . High-volume HIIT seems to be better for reducing body mass compared with low-volume HIIT . The exercise-induced improvement in cardiorespiratory fitness is intensity dependent with low-volume HIIT as a time-efficient method in this population . Clinical Trials.gov Registration : NCT02283047 Context Exercise training improves quality of life in patients with chronic obstructive pulmonary disease , but many of these patients can not tolerate continuous exercise . The effects of intermittent exercise are not known . Contribution The authors r and omly assigned 100 in patients with chronic obstructive pulmonary disease in a 3-week respiratory rehabilitation program to receive either high-intensity continuous exercise or high-intensity exercise alternating with low-intensity exercise ( interval exercise ) . After 5 weeks , the 2 groups had similar respiratory symptoms in daily activities and 6-minute walking distance , but the interval exercise group adhered better to the exercise protocol . Caution s The study focused on initiation of exercise and not on outpatient or home-based maintenance of exercise . Implication s For pulmonary rehabilitation , interval exercise is as effective as continuous high-intensity exercise and is better tolerated . The Editors Low exercise capacity is an important systemic manifestation of advanced chronic obstructive pulmonary disease ( COPD ) associated with poor health-related quality of life , exacerbations , and death ( 14 ) . Physical exercise , therefore , represents an important element of COPD management ( 5 , 6 ) . If performed under supervision during respiratory rehabilitation , exercise training improves health-related quality of life and may improve prognosis ( 79 ) . Dyspnea and leg fatigue limit the ability of patients with COPD to exercise , and patient response to exercise is highly variable ( 10 ) . It is challenging to find endurable exercise programs that are still effective . Current guidelines recommend endurance exercise at constant and high intensity ( 70 % of maximum exercise capacity ) ( 11 , 12 ) . For example , if a patient achieves 100 watts in an incremental exercise test , workload would be set at 70 watts for the entire exercise session of at least 20 minute 's duration . Strong evidence from r and omized trials shows that patients achieve clinical ly important improvements of health-related quality of life and exercise capacity with a continuous exercise protocol ( 1316 ) . However , patients with severe COPD are often unable to tolerate continuous exercise ( 17 ) , which can be frustrating for them and can limit their long-term adherence to exercise programs . Effective alternatives to continuous exercise are required to offer this important intervention to more patients with COPD . The American Thoracic Society and the European Respiratory Society state , on the basis of 2 r and omized trials ( 18 , 19 ) , that interval exercise may be an alternative . The benefits of interval exercise may be similar to those of continuous training , but this method is associated with less dyspnea ( 11 , 12 ) . Although studies indicated that interval exercise is well tolerated ( 1821 ) , evidence about its effectiveness relative to continuous exercise is inconclusive ; previous trials had method ological limitations and were small ( 22 ) . Because of perceived better tolerability of interval exercise , r and omized trials should be explicitly design ed to show that interval exercise is no less effective ( clinical noninferiority ) ( 22 ) . Thus , the aim of our trial was to assess whether interval exercise is no less effective than high-intensity continuous exercise in patients with severe COPD and whether patient tolerance of the interval exercise protocol is superior to that of continuous exercise . Methods Design Overview We conducted a r and omized , controlled noninferiority trial to compare the effects of interval exercise with those of high-intensity continuous exercise in patients with severe COPD . We previously described the detailed study protocol ( 23 ) and report this trial following the recommendations of the extended Consoli date d St and ards of Reporting Trials ( CONSORT ) statement for noninferiority and equivalence trials ( 24 ) . Setting The trial took place in a public rehabilitation clinic , Klinik Barmelweid , in Aargau , Switzerl and . The ethics committee of the Kantonsspital Aarau , Aargau , Switzerl and , approved the study protocol , and all study participants provided written informed consent . Participants We screened patients admitted to the respiratory medicine unit and included consecutive patients following inclusion criteria similar to those of previous respiratory rehabilitation trials ( 7 ) : COPD as defined by FEV1FVC ratio less than 70 % of predicted , FEV1 less than 50 % of predicted after bronchodilation corresponding to Global Initiative for Chronic Obstructive Lung Disease ( GOLD ) stage III to IV ( 5 ) , and German as first or daily language . Exclusion criteria included cardiovascular , musculoskeletal , or neurologic disorders that inhibited physical exercise or the performance of exercise tests ( 6 ) . We also excluded patients who had received a diagnosis of cancer ( excluding skin cancer ) within the past 2 years and were undergoing treatment . R and omization and Interventions A third party not involved in the execution of the trial ( DatInf GmbH , Tuebingen , Germany ) provided online central r and omization using a computerized minimization procedure , thereby ensuring concealment of r and omization ( 25 ) . Stratification variables were exercise capacity ( 6-minute walking distance < 300 or 300 meters ) , the presence of affective disorders ( Hospital Anxiety Depression Scale scores < or 8) , stability of pulmonary condition ( stable or exacerbation within the last 8 weeks ) , and the need for oxygen at rest ( Pao 2 < 55 mm Hg or 55 mm Hg ) . Patients followed an inpatient respiratory rehabilitation of approximately 3 week 's duration that included 12 to 15 exercise sessions . On weekdays , patients usually participated in 1 exercise session .  Twelve physical therapists worked with an approximately equal number of patients from both treatment groups . Apart from exercise , the rehabilitation program was identical for both groups and included breathing therapy , relaxation therapy , guided walking tours , and patient education ( 23 ) . At discharge , physiotherapists prescribed home-based exercise for each patient . Patients with cycle ergometers at home were instructed to exercise for at least 20 minutes per day . If no cycle ergometers were available , daily walking , swimming , or stair climbing was prescribed . High-Intensity Continuous Exercise Patients r and omly assigned to this intervention exercised on electromagnetically braked cycle ergometers ( Ergometrics 900S , Ergoline , Bitz , Germany ) with a target workload of 70 % or more of maximum exercise capacity ( Figure 1 ) . This exercise protocol has been used in earlier respiratory rehabilitation trials ( 7 ) . To determine maximum exercise capacity , patients pedaled unloaded for 3 minutes at 20 watts to warm up . Then , we used increments of 7.5 watts per minute until patients had to stop because of symptoms or cardiovascular stopping criteria . In each exercise session , patients completed a warm-up period of 2 minutes at 20 % of maximum exercise capacity , high-intensity exercise for 20 minutes , and a run-out phase of 2 minutes ( gradual decrease from 70 % to 0 % ) . If patients could not sustain the workload because of perceived dyspnea ( modified Borg [ 26 ] ratings > 5 on a scale from 0 to 10 ) or because heart rate exceeded safety limits , physical therapists let patients rest for 1 minute before continuing in the assigned phase . If patients had to rest more than twice per session , physical therapists lowered the workload by steps of 10 % of baseline maximum exercise capacity for the following exercise sessions . If workload was too low ( modified Borg ratings < 3 or patients or physical therapists considered the workload to be too low ) , physical therapists increased the workload by steps of 10 % of baseline maximum exercise capacity . Figure 1 . Exercise protocol s. Interval Exercise The target workload for this group was 50 % ( high-intensity intervals ) and 10 % ( low-intensity intervals ) of short-term maximum exercise capacity as determined by a steep ramp test ( 27 , 28 ) . The steep ramp test is an incremental cycle ergometer test in which patients pedal cycle ergometers unloaded for 2 minutes and then at increments of 25 watts every 10 seconds until they can not maintain a pedaling frequency above 50 pedals per minute or their heart rate exceeds the limit set by the normal incremental exercise test . We used the steep ramp test because workload for interval exercise can be underestimated if it is based on normal incremental exercise tests ( 28 ) . Fifty percent of short-term maximum exercise capacity corresponds , on average , to 90 % to 100 % of normal maximum exercise capacity ( 27 ) . We chose a workrecovery ratio of 1:2 that prevents high lactate accumulation and is well tolerated by patients ( 28 ) . In each session , patients had a warm-up period of 2 minutes at 10 % of the short-term maximum exercise capacity and then exercised for 20 minutes alternating between high-intensity intervals for 20 seconds and low-intensity intervals for 40 seconds ( Figure 1 ) . Patients also had a slowdown period of 2 minutes before completing the training session . We adjusted the exercise load for each patient individually if workload was too high or too low as described earlier ; physiotherapists lowered or increased the workload by steps of 10 % of short-term maximum exercise capacity , but the length of intervals remained constant ( 23 ) . Outcomes and Measurements Our primary outcome for effectiveness was the difference from baseline in Chronic Respiratory Question naire ( CRQ ) scores 5 weeks after r and omization as measured by the self-administered German- language version ( 29 , 30 ) with st and ardized dyspnea questions ( 31 ) . The CRQ is a widely used instrument in respiratory rehabilitation and measures dyspnea , fatigue , emotional functioning , and ability to cope with COPD ( 7 , 32 ) . Domain and total ( average of domains ) scores are presented on a Likert-type scale from 1 ( most severe impairment ) to 7 ( no impairment ) . We selected assessment at 5 weeks after r and omization as the primary outcome
The effects of HIIT appear to be comparable to those of continuous exercise in relation to functional and cardiovascular responses .
OBJECTIVE To evaluate the effects of high-intensity interval training ( HIIT ) , in comparison with those of continuous exercise , on functional capacity and cardiovascular variables in patients with COPD , through a systematic review and meta- analysis of r and omized controlled trials .