***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Most health organizations recommend a combination of aerobic training ( AT ) and resistance training ( RT ) , yet few studies have compared their acute ( within 24 h of the last exercise bout ) and sustained ( after 14 days of no exercise training ) effects alone and in combination on glucose metabolism . The present study ( Studies Targeting Risk Reduction Interventions through Defined Exercise-Aerobic Training and /or Resistance Training ) compared the effects of AT , RT , and the combination ( AT/RT ) on insulin action at both acute and sustained phases . Subjects ( N = 196 ) were 18 - 70 yr old ( mean age = 50 yr ) , overweight ( mean body mass index = 30 kg/m2 ) , sedentary with moderate dyslipidemia , and were r and omized into one of three 8-mo exercise groups : 1 ) RT : 3 days/wk , 8 exercises , 3 sets/exercise , 8 - 12 repetitions/set ; 2 ) AT : equivalent to ∼19.2 km/wk ( 12 miles/wk ) at 75 % peak O2 consumption ; 3 ) AT/RT : the combination of AT and RT . One hundred forty-four subjects completed the intervention . Eighty-eight subjects completed all pre- and postintervention testing visits . Insulin sensitivity , glucose effectiveness , and disposition index were measured via a frequently sample d intravenous glucose tolerance test with subsequent minimal model analyses . AT/RT result ed in greater improvements in insulin sensitivity , β-cell function ( disposition index ) , and glucose effectiveness than either AT or RT alone ( all P < 0.05 ) . Approximately 52 % of the improvement in insulin sensitivity by AT/RT was retained 14 days after the last exercise training bout . Neither AT or RT led to acute or chronic improvement in sensitivity index . In summary , only AT/RT ( which required twice as much time as either alone ) led to significant acute and sustained benefits in insulin BACKGROUND Weight loss , through calorie restriction or increases in energy expenditure via exercise , improves glucose tolerance and insulin action . However , exercise-induced energy expenditure may further improve glucoregulation through mechanisms independent of weight loss . OBJECTIVE The objective was to assess the hypothesis that weight loss through exercise-induced energy expenditure improves glucoregulation and circulating factors involved in insulin action to a greater extent than does similar weight loss through calorie restriction . DESIGN Sedentary men and women aged 50 - 60 y with a body mass index ( kg/m(2 ) ) of 23.5 - 29.9 were r and omly assigned to 1 of 2 weight-loss interventions [ 12 mo of exercise training ( EX group ; n = 18 ) or calorie restriction ( CR group ; n = 18 ) ] or to a healthy lifestyle ( HL ) control group ( n = 10 ) . The insulin sensitivity index and areas under the curve for glucose and insulin were assessed with an oral-glucose-tolerance test . Adiponectin and tumor necrosis factor alpha concentrations were measured in fasting serum . Fat mass was measured by dual-energy X-ray absorptiometry . RESULTS Yearlong energy deficits were not significantly different between the EX and CR groups , as evidence d by body weight and fat mass changes . The insulin sensitivity index increased and the glucose and insulin areas under the curve decreased in the EX and CR groups , remained unchanged in the HL group , and did not differ significantly between the EX and CR groups . Marginally significant increases in adiponectin and decreases in the ratio of tumor necrosis factor alpha to adiponectin occurred in the EX and CR groups but not in the HL group . CONCLUSIONS Weight loss induced by exercise training or calorie restriction improves glucose tolerance and insulin action in nonobese , healthy , middle-aged men and women . However , it does not appear that exercise training-induced  weight loss results in greater improvements than those that result from calorie restriction alone OBJECTIVE Observational studies show breaking up prolonged sitting has beneficial associations with cardiometabolic risk markers , but intervention studies are required to investigate causality . We examined the acute effects on postpr and ial glucose and insulin levels of uninterrupted sitting compared with sitting interrupted by brief bouts of light- or moderate-intensity walking . RESEARCH DESIGN AND METHODS Overweight/obese adults ( n = 19 ) , aged 45–65 years , were recruited for a r and omized three-period , three-treatment acute crossover trial : 1 ) uninterrupted sitting ; 2 ) seated with 2-min bouts of light-intensity walking every 20 min ; and 3 ) seated with 2-min bouts of moderate-intensity walking every 20 min . A st and ardized test drink was provided after an initial 2-h period of uninterrupted sitting . The positive incremental area under curves ( iAUC ) for glucose and insulin ( mean [ 95 % CI ] ) for the 5 h after the test drink ( 75 g glucose , 50 g fat ) were calculated for the respective treatments . RESULTS The glucose iAUC ( mmol/L ) ⋅ h after both activity-break conditions was reduced ( light : 5.2 [ 4.1–6.6 ] ; moderate : 4.9 [ 3.8–6.1 ] ; both P < 0.01 ) compared with uninterrupted sitting ( 6.9 [ 5.5–8.7 ] ) . Insulin iAUC ( pmol/L ) ⋅ h was also reduced with both activity-break conditions ( light : 633.6 [ 552.4–727.1 ] ; moderate : 637.6 [ 555.5–731.9 ] , P < 0.0001 ) compared with uninterrupted sitting ( 828.6 [ 722.0–950.9 ] ) . CONCLUSIONS Interrupting sitting time with short bouts of light- or moderate-intensity walking  lowers postpr and ial glucose and insulin levels  in overweight/obese adults . This may improve glucose metabolism and potentially be an important public health and clinical intervention strategy for reducing cardiovascular risk Aims /hypothesisThe aim of this study was to investigate whether small doses of intense exercise before each main meal ( ‘ exercise snacks ’ ) would result in better blood glucose control than a single bout of prolonged , continuous , moderate-intensity exercise in individuals with insulin resistance . Methods Nine individuals completed three exercise interventions in r and omised order . Measures were recorded across 3 days with exercise performed on the middle day , as either : ( 1 ) traditional continuous exercise ( CONT ) , comprising 30 min moderate-intensity ( 60 % of maximal heart rate [ HRmax ] ) incline walking before dinner ; ( 2 ) exercise snacking ( ES ) , consisting of 6 × 1 min intense ( 90 % HRmax ) incline walking intervals 30 min before each meal ; or ( 3 ) composite exercise snacking ( CES ) , encompassing 6 × 1 min intervals alternating between walking and resistance-based exercise , 30 min before meals . Meal timing and composition were controlled within participants for exercise interventions . Results ES attenuated mean 3 h postpr and ial glucose concentration following breakfast ( by 1.4 ± 1.5 mmol/l , p = 0.02 ) but not lunch ( 0.4 ± 1.0 mmol/l , p = 0.22 ) , and was more effective than CONT following dinner ( 0.7 ± 1.5 mmol/l below CONT ; p = 0.04 ) . ES also reduced 24 h mean glucose concentration by 0.7 ± 0.6 mmol/l ( p = 0.01 ) and this reduction persisted for the subsequent 24 h ( lower by 0.6 ± 0.4 mmol/l vs CONT , relative to their baselines ; p = 0.01 ) . CES was just as effective as ES ( p > 0.05 for all glycaemic variables ) at improving glycaemic control . Conclusions /interpretationDosing exercise as brief , intense ‘ exercise snacks ’ before main meals is a time-efficient and effective approach to improve glycaemic control in individuals with insulin resistance Physical activity enhances insulin action in obese/overweight individuals . However , the exercise prescription required for the optimal enhancement is not known . The purpose of this study was to test the hypothesis that exercise training consisting of vigorous-intensity activity would enhance insulin sensitivity more substantially than moderate-intensity activity . Sedentary , overweight/obese subjects ( n = 154 ) were r and omly assigned to either control or an exercise group for 6 mo : 1 ) low-volume/moderate-intensity group [ approximately 12 miles walking/wk at 40 - 55 % peak O2 consumption ( Vo2 peak ) ] , 2 ) low-volume/high-intensity group ( approximately 12 miles jogging/wk at 65 - 80 % Vo2 peak ) , and 3 ) high-volume/high-intensity group ( approximately 20 miles jogging/wk at 65 - 80 % Vo2 peak ) . Training volume ( miles/wk ) was achieved by exercising approximately 115 min/wk ( low-volume/high-intensity group ) or approximately 170 min/wk ( low-volume/moderate-intensity and high-volume/high-intensity groups ) . Insulin action was measured with an insulin sensitivity index ( SI ) from an intravenous glucose tolerance test . In the control group , there was a decrement ( P < 0.05 ) in SI . In contrast , all the exercise groups significantly ( P < 0.05 ) increased SI ; the relative increment in the low-volume/moderate-intensity and high-volume/high-intensity groups ( approximately 85 % ) were greater than in the low-volume/high-intensity group ( approximately 40 % ) . In conclusion , physical activity encompassing a wide range of intensity and volume minimizes the insulin resistance that develops with a sedentary lifestyle . However , an exercise prescription that incorporated approximately 170 min of exercise/wk improved insulin sensitivity more substantially than a program utilizing approximately 115 min of exercise/wk , regardless of exercise intensity and volume . Total exercise duration should thus be considered when design ing training programs with the intent of improving insulin action Adiponectin is an anti-inflammatory protein that reduced in obesity . Exercise training may reduce the adipose tissue ( AT ) , although it is not well known whether exercise-induced change in AT , increases the adiponectin mRNA expression and plasma concentrations or not ; therefore , the purpose of this study was to investigate the adiponectin mRNA and plasma concentrations in middle-aged men after 12 weeks high-intensity exercise training and after a week detraining .  Sixteen sedentary overweight and obese middle-aged men ( age 41.18 ± 6.1 years ; ± SD ) volunteered to participate in this study . The subjects were r and omly assigned to training group ( n = 8) or control group ( n = 8) . The training group performed endurance training 4 days a week for 12 weeks at an intensity corresponding to 75–80 % individual maximum oxygen consumption for 45 min . After 12 weeks of training , subjects underwent a week of detraining . The results showed that the BMI as well as central and peripheral AT volume were decreased in the training group compared to the control group ( P < 0.05 ) . After 12 weeks , the training group result ed in a significant increase ( P < 0.05 ) in the adiponectin gene expression in abdominal and gluteal subcutaneous AT when compared with the control group . The results showed that plasma adiponectin concentrations increased and insulin resistance decreased after training compared to the control group ( P < 0.05 ) . After a week of detraining , the variables were not changed significantly in the training group . In conclusion , high-intensity endurance training caused an increase adiponectin mRNA in obese middle-aged men Physical activity is a known modifiable lifestyle means for reducing postmenopausal breast cancer risk , but the biologic mechanisms are not well understood . Metabolic factors may be involved . In this study , we aim ed to determine the effects of exercise on insulin resistance ( IR ) indicators , IGF1 , and adipokines in postmenopausal women . The Alberta Physical Activity and Breast Cancer Prevention Trial was a two-armed r and omized controlled trial in postmenopausal , inactive , cancer-free women . A year-long aerobic exercise intervention of 225 min/week ( n=160 ) was compared with a control group asked to maintain usual activity levels ( n=160 ) . Baseline , 6- and 12-month serum levels of insulin , glucose , IGF1 , IGF-binding protein 3 ( IGFBP3 ) , adiponectin , and leptin were assayed , and after data collection , homeostasis model assessment of IR ( HOMA-IR ) scores were calculated . Intention-to-treat analyses were performed using linear mixed models . The treatment effect ratio ( TER ) of exercisers to controls was calculated . Data were available on 308 ( 96.3 % ) women at 6 months and 310 ( 96.9 % ) women at 12 months . Across the study period , statistically significant reductions in insulin ( TER=0.87 , 95 % confidence interval ( 95 % CI)=0.81–0.93 ) , HOMA-IR ( TER=0.86 , 95 % CI=0.80–0.93 
    Output:
    
Summary / conclusion The glycaemic response to accumulated exercise or single-bout exercise might not be different , however exercise intensity might influence the mechanisms generating the response .