title: The Effects of Two Modes of Exercise on Aerobic Fitness and Fat Mass in an Overweight Population Both aerobic endurance and strength training programmes improve cardiovascular health in obese adults. Energy-matched moderate and high intensity exercise training improves nonalcoholic fatty liver disease risk independent of changes in body mass or abdominal adiposity - A randomized trial. Novel all-extremity high-intensity interval training improves aerobic fitness, cardiac function and insulin resistance in healthy older adults The Effect of a High-Intensity Interval Training Program on High-Density Lipoprotein Cholesterol in Young Men High-intensity aerobic interval training improves aerobic fitness and HbA1c among persons diagnosed with type 2 diabetes Validation of a new tool for the assessment of study quality and reporting in exercise training studies: TESTEX Effects of interval and continuous running on HDL-cholesterol, apoproteins A-1 and B, and LCAT. High-intensity interval and moderate-intensity continuous training elicit similar enjoyment and adherence levels in overweight and obese adults Physical Activity and Reduced Risk of Cardiovascular Events: Potential Mediating Mechanisms A comparison of the health benefits of reduced-exertion high-intensity interval training (REHIT) and moderate-intensity walking in type 2 diabetes patients. High-intensity training versus traditional exercise interventions for promoting health. Continuous Exercise but Not High Intensity Interval Training Improves Fat Distribution in Overweight Adults The Effects of High Intensity Interval Training vs Steady State Training on Aerobic and Anaerobic Capacity. Enjoyment for High-Intensity Interval Exercise Increases during the First Six Weeks of Training: Implications for Promoting Exercise Adherence in Sedentary Adults High Intensity Interval Training in a Real World Setting: A Randomized Controlled Feasibility Study in Overweight Inactive Adults, Measuring Change in Maximal Oxygen Uptake Effects of self-paced interval and continuous training on health markers in women Effects of the amount and intensity of exercise on plasma lipoproteins. Effect of diet and exercise, alone or combined, on weight and body composition in overweight-to-obese postmenopausal women. Relationship between Fat Oxidation and Lactate Threshold in Athletes and Obese Women and Men. High-intensity interval training reduces abdominal fat mass in postmenopausal women with type 2 diabetes. The nuts and bolts of PROSPERO: an international prospective register of systematic reviews Changes in cardiorespiratory fitness and coronary heart disease risk factors following 24 wk of moderate- or high-intensity exercise of equal energy cost. Sprint interval and moderate-intensity continuous training have equal benefits on aerobic capacity, insulin sensitivity, muscle capillarisation and endothelial eNOS/NAD(P)Hoxidase protein ratio in obese men. High-Intensity Intermittent Swimming Improves Cardiovascular Health Status for Women with Mild Hypertension
abstract: We examined the effects of an 8-week exercise intervention on aerobic fitness , and roid and gynoid fat mass , and blood lipids in overweight and obese participants . Twenty-four sedentary participants ( average BMI = 30 ± 2 kg/m2 ; 18 females , 6 males ) were r and omized into either interval training and diet education ( INT group ) , continuous aerobic exercise and diet education ( CON group ) , or diet education only ( DIET group ) . Duration s of exercise sessions were similar ( ∼30 minutes ) , with both exercise groups completing the same amount of work . The INT and CON groups demonstrated significant improvements over time for ( p < 0.01 and p < 0.05 , ES = 1.1 and 1.2 , respectively ) and time to exhaustion on a grade d exercise test ( p < 0.01 and ES = 0.8 for both groups ) . Further , a large effect size ( 0.7 ) was recorded for the loss in and roid fat mass over time in the INT group only Regular exercise training is recognized as a powerful tool to improve work capacity , endothelial function and the cardiovascular risk profile in obesity , but it is unknown which of high-intensity aerobic exercise , moderate-intensity aerobic exercise or strength training is the optimal mode of exercise . In the present study , a total of 40 subjects were r and omized to high-intensity interval aerobic training , continuous moderate-intensity aerobic training or maximal strength training programmes for 12 weeks , three times/week . The high-intensity group performed aerobic interval walking/running at 85 - 95 % of maximal heart rate , whereas the moderate-intensity group exercised continuously at 60 - 70 % of maximal heart rate ; protocol s were isocaloric . The strength training group performed ' high-intensity ' leg press , abdominal and back strength training .  Maximal oxygen uptake and endothelial function improved in all groups ; the greatest improvement was observed after high-intensity training , and an equal improvement was observed after moderate-intensity aerobic training and strength training . High-intensity aerobic training and strength training were associated with increased PGC-1alpha ( peroxisome-proliferator-activated receptor gamma co-activator 1alpha ) levels and improved Ca(2 + ) transport in the skeletal muscle , whereas only strength training improved antioxidant status . Both strength training and moderate-intensity aerobic training decreased oxidized LDL ( low-density lipoprotein ) levels . Only aerobic training decreased body weight and diastolic blood pressure . In conclusion , high-intensity aerobic interval training was better than moderate-intensity aerobic training in improving aerobic work capacity and endothelial function . An important contribution towards improved aerobic work capacity , endothelial function and cardiovascular health originates from strength training , which may serve as a substitute when whole-body aerobic exercise is contra-indicated or difficult to perform BACKGROUND AND PURPOSE Exercise training is commonly prescribed for individuals diagnosed with nonalcoholic fatty liver disease ( NAFLD ) ; however , consensus regarding the volume and intensity of exercise for optimal benefits is lacking . Thus , we determined whether high intensity interval exercise training ( HIIT ) produced greater reductions in intrahepatic lipid ( IHL ) content and NAFLD risk factors compared with energy-matched moderate intensity continuous exercise training ( MICT ) in obese adults with liver steatosis . METHODS Eighteen obese adults were r and omized to either 4weeks of HIIT ( 4min 80 % VO2peak/3min , 50 % VO2peak ) or MICT ( 55 % VO2peak , ~60min ) , matched for energy expenditure ( ~400kcal/session ) and compared to five non-exercising age-matched control subjects .  IHL was measured by 1H-MRS and frequent blood sample s were analyzed for glucose , insulin , c-peptide , and NEFA levels during a liquid meal test ( 180min ) to characterize metabolic phenotype . RESULTS Baseline body weight , visceral abdominal adiposity , and fasting insulin concentrations were greater in the MICT vs HIIT group ( P<0.05 ) , while IHL was tightly matched between MICT and HIIT subjects ( P>0.05 ) , albeit higher than control subjects ( P<0.01 ) . Visceral abdominal adiposity , body mass , liver aminotransferases ( ALT , AST ) , and hepatic apoptotic/inflammatory markers ( cytokeratin 18 and fetuin a ) were not reduced with either exercise training intervention ( P>0.05 ) . Both HIIT and MICT lowered IHL ( HIIT , -37.0±12.4 % ; MICT , -20.1±6.6 % , P<0.05 ) ; however , the reduction in IHL was not statistically different between exercise intensities ( P=0.25 ) . Furthermore , exercise training decreased postpr and ial insulin , c-peptide , and lipid peroxidation levels ( iAUC , P<0.05 ) . CONCLUSIONS Collectively , these findings indicate that energy-matched high intensity and moderate intensity exercise are effective at decreasing IHL and NAFLD risk that is not contingent upon reductions in abdominal adiposity or body mass 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 Musa , DI , Adeniran , SA , Dikko , AU , and Sayers , SP . The effect of a high-intensity interval training program on high-density lipoprotein cholesterol in young men . J Strength Cond Res 23(2 ) : 587 - 592 , 2009-This study examined the impact of an 8-week program of high-intensity interval training on high-density lipoprotein cholesterol ( HDL-C ) , total cholesterol ( TC ) , and the atherogenic index ( TC/HDL-C ) in 36 untrained men ages 21 - 36 years . Participants were r and omly assigned to an interval training group ( n = 20 ) or a control group ( n = 16 ) . Participants in the experimental group performed 3.2 km of interval running ( 1:1 work : rest ratio ) 3 times a week for 8 weeks at an intensity of 90 % of maximal heart rate ( ∼423 kcal per session ) . Results indicated significant pre- to posttraining changes in HDL-C ( 1.1 vs. 1.3 mmol·L−1 , p < 0.0001 ) and TC/HDL-C ( 3.8 vs. 3.1 , p < 0.0001 ) but no significant changes in TC ( 3.9 vs. 3.8 mmol·L−1 , p > 0.05 ) with interval training . It was concluded that an 8-week program of high-intensity interval training is effective in eliciting favorable changes in HDL-C and TC/HDL-C but not TC in young adult men with normal TC levels . Our findings support the recommendations of high-intensity interval training as an alternative mode of exercise to improve blood lipid profiles for individuals with acceptable physical fitness levels Purpose It remains to be established how high-intensity aerobic interval training ( HAIT ) affects risk factors associated with type 2 diabetes ( TD2 ) . This study investigated effects of HAIT on maximal oxygen uptake ( VO2max ) , glycated Hemoglobin type A1C ( HbA1c ) , insulin resistance ( IR ) , fat oxidation ( FatOx ) , body weight ( BW ) , percent body fat ( % BF ) , lactate threshold ( LT ) , blood pressure ( BP ) , and blood lipid profile ( BLP ) among persons with T2D . Results were compared to the effects after a moderate-intensity training ( MIT ) program . Methods Thirty-eight individuals with T2D completed 12 weeks of supervised training . HAIT consisted of 4 × 4 min of walking or running uphill at 85–95 % of maximal heart rate , and MIT consisted of continuous walking at 70–75 % of maximal heart rate . Results A 21 % increase in VO2max ( from 25.6 to 30.9 ml kg−1 min−1 , p < 0.001 ) , and a reduction in HbA1c by −0.58 % points ( from 7.78 to 7.20 % , p < 0.001 ) was found in HAIT . BW and body mass index ( BMI ) was reduced by 1.9 % ( p < 0.01 ) . There was a tendency towards an improved FatOx at 60 % VO2max ( 14 % , p = 0.065 ) . These improvements were significant different from MIT . Both HAIT and MIT  increased velocity at LT , and reduced % BF , waist circumference , hip circumference , and BP , with no significant differences between the two groups . Correlations were found between change in VO2max and change in HbA1c when the two intervention groups were combined ( R = −0.52 , p < 0.01 ) . Conclusion HAIT is an effective exercise strategy to improve aerobic fitness and reduce risk factors associated with T2D Introduction : Several established tools are available to assess study quality and reporting of r and omized controlled trials ; however , these tools were design ed with clinical intervention trials in mind . In exercise training intervention trials some of the traditional study quality criteria , such as participant or research er blinding , are extremely difficult to implement . Methods : We developed the Tool for the assEssment of Study qualiTy and reporting in EXercise ( TESTEX ) – a study quality and reporting assessment tool , design ed specifically for use in exercise training studies . Our tool is a 15-point scale ( 5 points for study quality and 10 points for reporting ) and addresses previously unmentioned quality assessment criteria specific to exercise training studies . Results : There were no systematic differences between the summated TESTEX scores of each observer [ H(2 ) = 0.392 , P = 0.822 ] . There was a significant association between the summated TESTEX scores of the three observers , with almost perfect agreement between observers 1 and 2 [ intra-class correlation coefficient ( ICC ) = 0.93 , 95 % confidence interval ( CI ) 0.82–0.97 , P < 0.001 ] , observers 1 and 3 ( ICC = 0.96 , 95 % CI 0.89–0.98 , P < 0.001 ) and observers 2 and 3 ( ICC = 0.91 , 95 % CI 0.75–0.96 , P < 0.001 ) . Conclusions : The TESTEX scale is a new , reliable tool , specific to exercise scientists , that facilitates a comprehensive review of exercise training trials The purpose of this study was to examine the effect of interval and continuous exercise programs on plasma lipoproteins , apoproteins , and lecithin : cholesterol acyltransferase ( LCAT ) .  Thirty-six college male students ( age 18 - 25 yrs . ) were r and omly assigned to a 5 mile continuous exercise group , 4 minute interval ( 1:1 , work : rest ) , 2 minute interval ( 1:1 - 1/2 , work : rest ) , or control . Workloads were equated by kcal expenditure/workout . The training groups exercised for one hour three times a week for 11 weeks . Neither interval or continuous exercise programs significantly altered plasma total cholesterol , high density lipoprotein cholesterol ( HDL-C ) , apoprotein A-1 ( Apo A-1 ) , apoprotein B ( Apo B ) , or LCAT . Posttest maximal oxygen consumption was significantly higher than pretest for the 4 minute interval and 5 mile continuous groups . Thus continuous exercise and long interval programs result ed in gains in aerobic capacity , but none of the training programs were effective in altering the plasma lipoproteins or apoproteins investigated Abstract Background : High-intensity interval training ( HIIT ) has been shown to improve cardiometabolic health during supervised lab-based studies but adherence , enjoyment , and health benefits of HIIT performed independently are yet to be understood . We compared adherence , enjoyment , and cardiometabolic outcomes after 8 weeks of HIIT or moderate-intensity continuous training ( MICT ) , matched for energy expenditure , in overweight and obese young adults . Methods : 17 adults were r and omized to HIIT or MICT .  After completing 12 sessions of supervised training over 3 weeks , participants were asked to independently perform HIIT or MICT for 30 min , 4 times/week for 5 weeks . Cardiometabolic outcomes included cardiorespiratory fitness ( VO2 peak ) , lipids , and inflammatory markers . Exercise enjoyment was measured by the vali date d Physical Activity Enjoyment Scale . Results : Exercise adherence ( 93.4 ± 3.1 % vs. 93.1 ± 3.7 % , respectively ) and mean enjoyment across the intervention ( 100.1 ± 4.3 vs. 100.3 ± 4.4 , respectively ) were high , with no differences between HIIT and MICT ( p > .05 ) . Similarly , enjoyment levels did not change over time in either group ( p > .05 ) . After training , HIIT exhibited a greater decrease in low-density lipoprotein cholesterol than MICT ( −0.66 mmol L−1 vs. −0.03 mmol L−1 , respectively ) and a greater increase in VO2 peak than MICT ( p < .05 , + 2.6 mL kg min−1 vs. + 0.4 mL kg min−1 , respectively ) . Interleukin-6 and C-reactive protein increased in HIIT ( + 0.5 pg mL−1 and + 31.4 nmol L−1 , respectively ) and decreased in MICT ( −0.6 pg mL−1 and −6.7 nmol L−1 , respectively , p < .05 ) . Conclusions : Our novel findings suggest that HIIT is enjoyable and has high unsupervised adherence rates in overweight and obese adults . However , HIIT may be associated with an increase in inflammation with short-term exercise in this population Background — Higher levels of physical activity are associated with fewer cardiovascular disease  (  CVD ) events . Although the precise mechanisms underlying this inverse association are unclear , differences in several cardiovascular risk factors may mediate this effect . Methods and Results — In a prospect i ve study of 27 055 apparently healthy women , we measured baseline levels of hemoglobin A1c , traditional lipids ( total , low-density lipoprotein , and high-density lipoprotein cholesterol ) , novel lipids [ lipoprotein(a ) and apolipoprotein A1 and B-100 ] , creatinine , homocysteine , and inflammatory/hemostatic biomarkers  ( high-sensitivity C-reactive protein , fibrinogen , soluble intracellular adhesion molecule-1 ) and used women 's self-reported physical activity , weight , height , hypertension , and diabetes . Mean follow-up was 10.9±1.6 years , and 979 incident CVD events occurred . The risk of CVD decreased linearly with higher levels of activity ( P for linear trend < 0.001 ) . Using the reference group of < 200 kcal/wk of activity yielded age- and treatment-adjusted relative risk reductions associated with 200 to 599 , 600 to 1499 , and ≥1500 kcal/wk of 27 % , 32 % , and 41 % , respectively . Differences in known risk factors explained a large proportion ( 59.0 % ) of the observed inverse association . When sets of risk factors were examined , inflammatory/hemostatic biomarkers made the largest contribution to lower risk ( 32.6 % ) , followed by blood pressure ( 27.1 % ) . Novel lipids contributed less to CVD risk reduction compared with traditional lipids ( 15.5 % and 19.1 % , respectively ) . Smaller contributions were attributed to body mass index ( 10.1 % ) and hemoglobin A1c/diabetes ( 8.9 % ) , whereas homocysteine and creatinine had negligible effects ( < 1 % ) . Conclusions — The inverse association between  physical activity  and CVD risk is mediated in substantial part by known risk factors , particularly inflammatory/hemostatic factors and blood pressure Reduced-exertion high-intensity interval training ( REHIT ) is a genuinely time-efficient intervention that can improve aerobic capacity and insulin sensitivity in sedentary individuals . The present study compared the effects of REHIT and moderate-intensity walking  on health markers in patients with type 2 diabetes ( T2D ) in a counter-balanced crossover study . Sixteen men with T2D ( mean ± SD age : 55 ± 5 years , body mass index : 30.6 ± 2.8 kg·m-2 , maximal aerobic capacity : 27 ± 4 mL·kg-1·min-1 ) completed 8 weeks of REHIT ( three 10-min low-intensity cycling sessions/week with two " all-out " 10 - 20-s sprints ) and 8 weeks of moderate-intensity walking ( five 30-min sessions/week at an intensity corresponding to 40%-55 % of heart-rate reserve ) , with a 2-month wash-out period between interventions . Before and after each intervention , participants underwent an incremental fitness test , an oral glucose tolerance test ( OGTT ) , a whole-body dual-energy X-ray absorptiometry scan , and continuous glucose monitoring . REHIT was associated with a significantly larger increase in maximal aerobic capacity compared with walking ( 7 % vs. 1 % ; time × intervention interaction effect : p < 0.05 ) . Both REHIT and walking decreased resting mean arterial pressure ( -4 % ; main effect of time : p < 0.05 ) and plasma fructosamine ( -5 % ; main effect of time : p < 0.05 ) . Neither intervention significantly improved OGTT-derived measures of insulin sensitivity , glycaemic control measured using continuous glucose monitors , blood lipid profile , or body composition . We conclude that REHIT is superior to a 5-fold larger volume of moderate-intensity walking in improving aerobic fitness , but similar to walking REHIT is not an effective intervention for improving insulin sensitivity or glycaemic control in T2D patients in the short term PURPOSE The purpose of this study was to determine the effectiveness of brief intense interval training as exercise intervention for promoting health and to evaluate potential benefits about common interventions , that is , prolonged exercise and strength training . METHODS Thirty-six untrained men were divided into groups that completed 12 wk of intense interval running ( INT ; total training time 40 min wk(-1 ) ) , prolonged running ( approximately 150 min wk(-1 ) ) , and strength training ( approximately 150 min wk(-1 ) ) or continued their habitual lifestyle without participation in physical training . RESULTS The improvement in cardiorespiratory fitness was superior in the INT ( 14 % + /- 2 % increase in V˙O2max ) compared with the other two exercise interventions ( 7 % + /- 2 % and 3 % + /- 2 % increases ) . The blood glucose concentration 2 h after oral ingestion of 75 g of glucose was lowered to a similar extent after training in the INT ( from 6.1 + /- 0.6 to 5.1 + /- 0.4 mM , P < 0.05 ) and the prolonged running group ( from 5.6 + /- 1.5 to 4.9 + /- 1.1 mM , P < 0.05 ) . In contrast , INT was less efficient than prolonged running for lowering the subjects ' resting HR , fat percentage , and reducing the ratio between total and HDL plasma cholesterol . Furthermore , total bone mass and lean body mass remained unchanged in the INT group , whereas both these parameters were increased by the strength-training intervention . CONCLUSIONS INT for 12 wk is an effective training stimulus for improvement of cardiorespiratory fitness and glucose tolerance , but in relation to the treatment of hyperlipidemia and obesity , it is less effective than prolonged training . Furthermore and in contrast to strength training , 12 wk of INT had no impact on muscle mass or indices of skeletal health 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 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 This is the first study to show that enjoyment for high-intensity interval exercise increases with chronic training . Prior acute studies typically report high-intensity interval training ( HIT ) as being more enjoyable than moderate continuous training ( MCT ) unless the high-intensity intervals are too strenuous or difficult to complete . It follows that exercise competency may be a critical factor contributing to the enjoyment of HIT , and therefore building competency through chronic training may be one way to increase its enjoyment . To test this , we r and omly assigned sedentary young adults to six weeks of HIT or MCT , and tracked changes in their enjoyment for the exercise . Enjoyment for HIT increased with training whereas enjoyment for MCT remained constant and lower . Changes in exercise enjoyment were predicted by increases in workload , suggesting that strength adaptions may be important for promoting exercise enjoyment . The results point to HIT as a promising protocol for promoting exercise enjoyment and adherence in sedentary young adults Background In research clinic setting s , overweight adults undertaking HIIT ( high intensity interval training )  improve their fitness as effectively as those undertaking conventional walking programs but can do so within a shorter time spent exercising . We undertook a r and omized controlled feasibility ( pilot ) study aim ed at extending HIIT into a real world setting by recruiting overweight/obese , inactive adults into a group based activity program , held in a community park . Methods Participants were allocated into one of three groups . The two interventions , aerobic interval training and maximal volitional interval training , were compared with an active  control group undertaking walking based exercise . Supervised group sessions ( 36 per intervention ) were held outdoors . Cardiorespiratory fitness was measured using VO2max ( maximal oxygen uptake , results expressed in ml/min/kg ) , before and after the 12 week interventions . Results On ITT ( intention to treat ) analyses , baseline ( N = 49 ) and exit ( N = 39 ) O2 was 25.3±4.5 and 25.3±3.9 , respectively . Participant allocation and baseline/exit VO2max by group was as follows : Aerobic interval training N = 16 , 24.2±4.8/25.6±4.8 ; maximal volitional interval training N = 16 , 25.0±2.8/25.2±3.4 ; walking N = 17 , 26.5±5.3/25.2±3.6 . The post intervention change in VO2max was + 1.01 in the aerobic interval training , −0.06 in the maximal volitional interval training and −1.03 in the walking subgroups . The aerobic interval training subgroup increased VO2max compared to walking ( p = 0.03 ) . The actual ( observed , rather than prescribed ) time spent exercising ( minutes per week , ITT analysis ) was 74 for aerobic interval training , 45 for maximal volitional interval training and 116 for walking ( p = 0.001 ) . On descriptive analysis , the walking subgroup had the fewest adverse events . Conclusions In contrast to earlier studies , the improvement in cardiorespiratory fitness in a cohort of overweight/obese participants  undertaking aerobic interval training in a real world setting was modest . The most likely reason for this finding relates to reduced adherence to the exercise program , when moving beyond the research clinic setting . Trial Registration ACTR.org.au Purpose To compare the effects of self-paced high-intensity interval and continuous cycle training on health markers in premenopausal women . Methods Forty-five inactive females were r and omised to a high-intensity interval training ( HIIT ; n = 15 ) , continuous training ( CT ; n = 15 ) or an inactive control ( CON ; n = 15 ) group . HIIT performed 5 × 5 min sets comprising repetitions of 30-s low- , 20-s moderate- and 10-s high-intensity cycling with 2 min rest between sets . CT completed 50 min of continuous cycling . Training was completed self-paced , 3 times weekly for 12 weeks . Results Peak oxygen uptake ( 16 ± 8 and 21 ± 12 % ) , resting heart rate ( HR ) ( −5 ± 9 and −4 ± 7 bpm ) and visual and verbal learning improved following HIIT and CT compared to CON ( P < 0.05 ) . Total body mass ( −0.7 ± 1.4 kg ) , submaximal walking HR ( −3 ± 4 bpm ) and verbal memory were enhanced following HIIT ( P < 0.05 ) , whereas mental well-being , systolic ( −5 ± 6 mmHg ) and mean arterial ( −3 ± 5 mmHg ) blood pressures were improved following CT ( P < 0.05 ) . Participants reported similar levels of enjoyment following HIIT and CT , and there were no changes in fasting serum lipids , fasting blood [ glucose ] or [ glucose ] during an oral glucose tolerance test following either HIIT or CT ( P > 0.05 ) . No outcome variable changed in the CON group ( P > 0.05 ) . Conclusions Twelve weeks of self-paced HIIT and CT were similarly effective at improving cardiorespiratory fitness , resting HR and cognitive function in inactive premenopausal women , whereas blood pressure , submaximal HR , well-being and body mass adaptations were training-type-specific . Both training methods improved established health markers , but the adaptations to HIIT were evoked for a lower time commitment BACKGROUND Increased physical activity is related to reduced risk of cardiovascular disease , possibly because it leads to improvement in the lipoprotein profile . However , the amount of exercise training required for optimal benefit is unknown . In a prospect i ve , r and omized study , we investigated the effects of the amount and intensity of exercise on lipoproteins . METHODS A total of 111 sedentary , overweight men and women with mild-to-moderate dyslipidemia were r and omly assigned to participate for six months in a control group or for approximately eight months in one of three exercise groups : high-amount-high-intensity exercise , the caloric equivalent of jogging 20 mi ( 32.0 km ) per week at 65 to 80 percent of peak oxygen consumption ; low-amount-high-intensity exercise , the equivalent of jogging 12 mi ( 19.2 km ) per week at 65 to 80 percent of peak oxygen consumption ; or low-amount-moderate-intensity exercise , the equivalent of walking 12 mi per week at 40 to 55 percent of peak oxygen consumption . Subjects were encouraged to maintain their base-line body weight . The 84 subjects who complied with these guidelines served as the basis for the main analysis . Detailed lipoprotein profiling was performed by nuclear magnetic resonance spectroscopy with verification by measurement of cholesterol in lipoprotein subfractions . RESULTS There was a beneficial effect of exercise on a variety of lipid and lipoprotein variables , seen most clearly with the high amount of  high-intensity exercise .  The high amount of exercise result ed in greater improvements than did the lower amounts of exercise ( in 10 of 11 lipoprotein variables ) and was always superior to the control condition ( 11 of 11 variables ) . Both lower-amount exercise groups always had better responses than the control group ( 22 of 22 comparisons ) . CONCLUSIONS The highest amount of weekly exercise , with minimal weight change , had widespread beneficial effects on the lipoprotein profile . The improvements were related to the amount of activity and not to the intensity of exercise or improvement in fitness Lifestyle interventions for weight loss are the cornerstone of obesity therapy , yet their optimal design is debated . This is particularly true for postmenopausal women ; a population with a high prevalence of obesity yet toward whom fewer studies are targeted . We conducted a year-long , 4-arm r and omized trial among 439 overweight-to-obese postmenopausal sedentary women to determine the effects of a calorie-reduced , low-fat diet ( D ) , a moderate-intensity , facility-based aerobic exercise program ( E ) , or the combination of both interventions ( D+E ) , vs. a no-lifestyle-change control ( C ) on change in body weight and composition . The group-based dietary intervention had a weight-reduction goal of ≥10 % , and the exercise intervention consisted of a gradual escalation to 45-min aerobic exercise 5 day/week . Participants were predominantly non-Hispanic whites ( 85 % ) with a mean age of 58.0 ± 5.0 years , a mean BMI of 30.9 ± 4.0 kg/m(2 ) and an average of 47.8 ± 4.4 % body fat .  Baseline and 12-month weight and adiposity measures were obtained by staff blinded to participants ' intervention assignment . Three hundred and ninety nine women completed the trial ( 91 % retention ) . Using an intention-to-treat analysis , average weight loss at 12 months was -8.5 % for the D group ( P < 0.0001 vs. C ) , -2.4 % for the E group ( P = 0.03 vs. C ) , and -10.8 % for the D+E group ( P < 0.0001 vs. C ) , whereas the C group experienced a nonsignificant -0.8 % decrease . BMI , waist circumference , and % body fat were also similarly reduced . Among postmenopausal women , lifestyle-change involving diet , exercise , or both combined over 1 year improves body weight and adiposity , with the greatest change arising from the combined intervention The first aim of this study was to determine the exercise intensity that elicited the highest rate of fat oxidation  in sedentary , obese subjects ( OB ; n=10 men , n=10 women ) compared with endurance athletes ( AT ; n=10 men , n=10 women ) . The second aim was to investigate the relationship between VO2 at the intensity eliciting the highest rate of fat oxidation and the corresponding VO2 at the lactate threshold . Peak oxygen consumption ( VO2peak ) was determined in 20 AT and 20 OB using an incremental exercise protocol on a cycle ergometer . Based on their VO2peak values , subjects completed a protocol requiring them to exercise for 20 min at three different workloads ( 55 , 65 and 75 % VO2peak ) , r and omly assigned on two separate occasions . The oxidation rates of fat and carbohydrate were measured by indirect calorimetry . The highest rates of fat oxidation were at 75 % VO2peak ( AT ) , and at 65 % VO2peak ( OB ) . The rate of fat oxidation was significantly higher in AT ( 18.2 ± 6.1 ) compared with OB women ( 10.6 ± 4.5 kJ min(-1)·kg(-1 ) ) ( p < 0.01 ) . There was no significant difference in the rate of fat oxidation for the men ( AT 19.7 ± 8.1 vs. OB 17.6 ± 8.2 kJ min(-1)·kg(-1 ) ) . AT reached LT at a significantly ( p < 0.01 ) higher exercise intensity expressed in VO2peak than obese subjects ( AT women 76.4 ± 0.1 , men 77.3 ± 0.1 vs. OB women , 49.7 ± 0.1 , men 49.5 ± 0.1 % VO2peak ) . A significant correlation was found between VO2 at LT and VO2 ( L·min(-1 ) ) eliciting the maximal rate of fat oxidation in athletes ( women ; r = 0.67 ; p = 0.03 ; men : r = 0.75 ; p = 0.01 ) but not in the obese . In summary , we observed higher rates of fat oxidation at higher relative work rates in AT compared with OB . A significant correlation was found between LT and the exercise intensity eliciting a high rate of fat oxidation in AT ( r=0.89 ; p < 0.01 ) but not in OB . Cardiorespiratory fitness , defined as VO2peak , seems to be important in defining the relationship between a high rate of fat oxidation and LT . Key PointsWithin the tested intensities of 55 , 65 and 75 % VO2peak athletes reached higher rates of fat oxidation at higher relative work rates compared with obese subjects . We found in obese women and men the intensity of the highest rate of fat oxidation at 65 % VO2peak . Between the lactate threshold and the intensity eliciting a high rate of fat oxidation a significant correlation was found in athletes but not in obese subjects AIM This study compared the effect of high-intensity interval training ( HIIT ) and moderate-intensity continuous training ( MICT ) for 16 weeks on whole-body and abdominal fat mass ( FM ) in postmenopausal women with type 2 diabetes ( T2D ) . METHODS Seventeen women ( 69±1 years ; BMI : 31±1kg.m-2 ) were r and omly assigned to either a HIIT [ 60 × (8s at 77 - 85 % HRmax , 12s of active recovery ) ] or MICT ( 40min at 55 - 60 % of their individual HRR ) cycling program for 16 weeks , 2 days/week . Dual-energy X-ray absorptiometry was used to measure whole-body and regional FM content , including abdominal adiposity and visceral adipose tissue . Plasma cholesterol , HDL , LDL , triglycerides , glucose and HbA1c levels were measured . Levels of nutritional intake and physical activity were evaluated by 7-day self-reports . RESULTS Dietary energy ( caloric ) intake , physical activity level and total body mass did not vary in either group from the beginning to the end of the training intervention . Overall , total FM decreased and total fat-free mass significantly increased over time ( by around 2 - 3 % ) . Total FM reduction at the end of the intervention was not significantly different between groups . However , significant loss of total abdominal ( -8.3±2.2 % ) and visceral ( -24.2±7.7 % ) FM was observed only with HIIT . Time effects were noted for HbA1c and total cholesterol/HDL ratio . CONCLUSION With no concomitant caloric restriction , an HIIT program in postmenopausal women with T2D ( twice a week for 16 weeks ) appeared to be more effective for reducing central obesity than MICT , and could be proposed as an alternative exercise training program for this population Background Following publication of the PRISMA statement , the UK Centre for Review s and Dissemination ( CRD ) at the University of York in Engl and began to develop an international prospect i ve register of systematic review s with health-related outcomes . The objectives were to reduce unplanned duplication of review s and provide transparency in the review process , with the aim of minimizing reporting bias . Methods An international advisory group was formed and a consultation undertaken to establish the key items necessary for inclusion in the register and to gather views on various aspects of functionality . This article describes the development of the register , now called PROSPERO , and the process of registration . Results PROSPERO offers free registration and free public access to a unique prospect i ve register of systematic review s across all areas of health from all around the world . The dedicated web-based interface is electronically search able and available to all prospect i ve registrants . At the moment , inclusion in PROSPERO is restricted to systematic review s of the effects of interventions and strategies to prevent , diagnose , treat , and monitor health conditions , for which there is a health-related outcome .Ideally , registration should take place before the research ers have started formal screening against inclusion criteria but review s are eligible as long as they have not progressed beyond the point of completing data extraction .The required data set captures the key attributes of review design as well as the administrative details necessary for registration .Su bmi tted registration forms are checked against the scope for inclusion in PROSPERO and for clarity of content before being made publicly available on the register , rejected , or returned to the applicant for clarification . The public records include an audit trail of major changes to planned methods , details of when the review has been completed , and links to result ing publications when provided by the authors . Conclusions There has been international support and an enthusiastic response to the principle of prospect i ve registration of protocol s for systematic review s and to the development of PROSPERO .In October 2011 , PROSPERO contained 200 records of systematic review s being undertaken in 26 countries around the world on a diverse range of interventions This study was design ed to investigate the effect of exercise intensity on cardiorespiratory fitness and coronary heart disease risk factors . Maximum oxygen consumption ( Vo(2 max ) ) , lipid , lipoprotein , and fibrinogen concentrations were measured in 64 previously sedentary men before r and om allocation to a nonexercise control group , a moderate-intensity exercise group ( three 400-kcal sessions per week at 60 % of Vo(2 max ) ) , or a high-intensity exercise group ( three 400-kcal sessions per week at 80 % of Vo(2 max ) ) . Subjects were instructed to maintain their normal dietary habits , and training heart rates were represcribed after monthly fitness tests . Forty-two men finished the study . After 24 wk , Vo(2 max ) increased by 0.38 + /- 0.14 l/min in the moderate-intensity group and by 0.55 + /- 0.27 l/min in the high-intensity group . Repeated- measures analysis of variance identified a significant interaction between monthly Vo(2 max ) score and exercise group ( F = 3.37 , P < 0.05 ) , indicating that Vo(2 max ) responded differently to moderate- and high-intensity exercise . Trend analysis showed that total cholesterol , low-density lipoprotein cholesterol , non-high-density lipoprotein cholesterol , and fibrinogen concentrations changed favorably across control , moderate-intensity , and high-intensity groups . However , significant changes in total cholesterol ( -0.55 + /- 0.81 mmol/l ) , low-density lipoprotein cholesterol ( -0.52 + /- 0.80 mmol/l ) , and non-high-density lipoprotein cholesterol ( -0.54 + /- 0.86 mmol/l ) were only observed in the high-intensity group ( all P < 0.05 vs. controls ) . These data suggest that high-intensity training is more effective in improving cardiorespiratory fitness than moderate-intensity training of equal energy cost . These data also suggest that changes in coronary heart disease risk factors are influenced by exercise intensity KEY POINTS Skeletal muscle capillary density and vasoreactivity are reduced in obesity , due to reduced nitric oxide bioavailability . Sprint interval training ( SIT ) has been proposed as a time efficient alternative to moderate-intensity continuous training ( MICT ) , but its effect on the skeletal muscle microvasculature has not been studied in obese individuals . We observed that SIT and MICT led to equal increases in capillarisation and endothelial eNOS content , while reducing endothelial NOX2 content in microvessels of young obese men . We conclude that SIT is equally effective at improving skeletal muscle capillarisation and endothelial enzyme balance , while being a time efficient alternative to traditional MICT . ABSTRACT Sprint interval training ( SIT ) has been proposed as a time efficient alternative to moderate-intensity continuous training ( MICT ) , leading to similar improvements in skeletal muscle capillary density and microvascular function in young healthy humans . In this study we made the first comparisons of the muscle microvascular response to SIT and MICT in an obese population . Sixteen young obese men ( age 25 ± 1 years , BMI 34.8 ± 0.9 kg m(-2 ) ) were r and omly assigned to 4 weeks of MICT ( 40 - 60 min cycling at ∼65 % V̇O2 peak , 5 times per week ) or constant load SIT ( 4 - 7 constant workload intervals of 200 % Wmax 3 times per week ) . Muscle biopsies were taken before and after training from the m. vastus lateralis to measure muscle microvascular endothelial eNOS content , eNOS serine(1177 ) phosphorylation , NOX2 content and capillarisation using quantitative immunofluorescence microscopy . Maximal aerobic capacity ( V̇O2 peak ) , whole body insulin sensitivity and arterial stiffness were also assessed . SIT and MICT  increased skeletal muscle microvascular eNOS content and eNOS ser(1177 ) phosphorylation in terminal arterioles and capillaries ( P < 0.05 ) , but the latter effect was eliminated when normalised to eNOS content ( P = 0.217 ) . SIT and MICT also reduced microvascular endothelial NOX2 content ( P < 0.05 ) and both increased capillary density and capillary-fibre perimeter exchange index ( P < 0.05 ) . In parallel , SIT and MICT increased V̇O2 peak ( P < 0.05 ) and whole body insulin sensitivity ( P < 0.05 ) , and reduced central artery stiffness ( P < 0.05 ) . As no significant differences were observed between SIT and MICT it is concluded that SIT is a time efficient alternative to MICT to improve aerobic capacity , insulin sensitivity and muscle capillarisation and endothelial eNOS/NAD(P)Hoxidase protein ratio in young obese men To test the hypothesis that high-intensity swim training improves cardiovascular health status in sedentary premenopausal women with mild hypertension , sixty-two women were r and omized into high-intensity ( n = 21 ; HIT ) , moderate-intensity ( n = 21 ; MOD ) , and control groups ( n = 20 ; CON ) . HIT performed 6 - 10 × 30 s all-out swimming interspersed by 2 min recovery and MOD swam continuously for 1 h at moderate intensity for a 15-week period completing in total 44 ± 1 and 43 ± 1 sessions , respectively . In CON , all measured variables were similar before and after the intervention period . Systolic BP decreased ( P < 0.05 ) by 6 ± 1 and 4 ± 1 mmHg in HIT and MOD ; respectively . Resting heart rate declined ( P < 0.05 ) by 5 ± 1 bpm both in HIT and MOD , fat mass decreased ( P < 0.05 ) by 1.1 ± 0.2 and 2.2 ± 0.3 kg , respectively , while the blood lipid profile was unaltered . In HIT and MOD , performance improved ( P < 0.05 ) for a maximal 10 min swim ( 13 ± 3 % and 22 ± 3 % ) , interval swimming ( 23 ± 3 % and 8 ± 3 % ) , and Yo-Yo IE1 running performance ( 58 ± 5 % and 45 ± 4 % ) . In conclusion , high-intensity intermittent swimming is an effective training strategy to improve cardiovascular health and physical performance in sedentary women with mild hypertension . Adaptations are similar with high- and moderate-intensity training , despite markedly less total time spent and distance covered in the high-intensity group
target: Conclusion Neither HIIT nor MICT is superior for altering TC , TRG , or LDL-C , or TC-HDL-C ratio .
  To raise HDL-C , HIIT may result in a larger effect size compared with MICT .
background: Objective To compare the effects of moderate intensity continuous training ( MICT ) and high intensity interval training ( HIIT ) on  adult lipid profiles ;  to identify training or participant characteristics that may determine exercise-induced change in total cholesterol ( TC ) , triglycerides ( TRG ) , high-density lipoprotein cholesterol ( HDL-C ) and low-density lipoprotein cholesterol ( LDL-C ) .