***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: Background — Exercise training reduces the symptoms of chronic heart failure . Which exercise intensity yields maximal beneficial adaptations is controversial . Furthermore , the incidence of chronic heart failure increases with advanced age ; it has been reported that 88 % and 49 % of patients with a first diagnosis of chronic heart failure are > 65 and > 80 years old , respectively . Despite this , most previous studies have excluded patients with an age > 70 years . Our objective was to compare training programs with moderate versus high exercise intensity with regard to variables associated with cardiovascular function and prognosis in patients with postinfa rct ion heart failure . Methods and Results — Twenty-seven patients with stable postinfa rct ion heart failure who were undergoing optimal medical treatment , including & bgr;-blockers and angiotensin-converting enzyme inhibitors ( aged 75.5±11.1 years ; left ventricular [ LV ] ejection fraction 29 % ; & OV0312;o2peak 13 mL · kg−1 · min−1 ) were r and omized to either moderate continuous training ( 70 % of highest measured heart rate , ie , peak heart rate ) or aerobic interval training ( 95 % of peak heart rate ) 3 times per week for 12 weeks or to a control group that received st and ard advice regarding physical activity . & OV0312;o2peak increased more with aerobic interval training than moderate continuous training ( 46 % versus 14 % , P<0.001 ) and was associated with reverse LV remodeling . LV end-diastolic and end-systolic volumes declined with aerobic interval training only , by 18 % and 25 % , respectively ; LV ejection fraction increased 35 % , and pro-brain natriuretic peptide decreased 40 % . Improvement in brachial artery flow-mediated dilation ( endothelial function ) was greater with aerobic interval training , and mitochondrial function in lateral vastus muscle increased with aerobic interval training only . The MacNew global score for quality of life in cardiovascular disease increased in both exercise groups . No changes occurred in the control group . Conclusions — Exercise intensity was an important factor for reversing LV remodeling and improving aerobic capacity , endothelial function , and quality of life in patients with postinfa rct ion heart failure . These findings may have important implication s for exercise training in rehabilitation programs and future studies Abstract Hypoxia is an important modulator of endurance exercise‐induced oxidative adaptations in skeletal muscle . However , whether hypoxia affects resistance exercise‐induced muscle adaptations remains unknown . Here , we determined the effect of resistance exercise training under systemic hypoxia on muscular adaptations known to occur following both resistance and endurance exercise training , including muscle cross‐sectional area ( CSA ) , one‐repetition maximum ( 1RM ) , muscular endurance , and makers of mitochondrial biogenesis and angiogenesis , such as peroxisome proliferator‐activated receptor‐γ coactivator‐1α ( PGC‐1α ) , citrate synthase ( CS ) activity , nitric oxide synthase ( NOS ) , vascular endothelial growth factor ( VEGF ) , hypoxia‐inducible factor‐1 ( HIF‐1 ) , and capillary‐to‐fiber ratio . Sixteen healthy male subjects were r and omly assigned to either a normoxic resistance training group ( NRT , n = 7 ) or a hypoxic ( 14.4 % oxygen ) resistance training group ( HRT , n = 9 ) and performed 8 weeks of resistance training .  Blood and muscle biopsy sample s were obtained before and after training . After training muscle CSA of the femoral region , 1RM for bench‐press and leg‐press , muscular endurance , and skeletal muscle VEGF protein levels significantly increased in both groups . The increase in muscular endurance was significantly higher in the HRT  group . Plasma VEGF concentration and skeletal muscle capillary‐to‐fiber ratio were significantly higher in the HRT group than the NRT group following training . Our results suggest that , in addition to increases in muscle size and strength , HRT may also lead to increased muscular endurance and the promotion of angiogenesis in skeletal muscle We hypothesized that specific muscular transcript level adaptations participate in the improvement of endurance performances following intermittent hypoxia training  in endurance-trained subjects . Fifteen male high-level , long-distance runners integrated a modified  living low-training high program comprising two weekly controlled training sessions performed at the second ventilatory threshold for 6 wk into their normal training schedule . The athletes were r and omly assigned to either a normoxic ( Nor ) ( inspired O2 fraction = 20.9 % , n = 6 ) or a hypoxic group exercising under normobaric hypoxia ( Hyp ) ( inspired O2 fraction = 14.5 % , n = 9 ) . Oxygen uptake and speed at second ventilatory threshold , maximal oxygen uptake ( VO2 max ) , and time to exhaustion ( Tlim ) at constant load at VO2 max velocity in normoxia and muscular levels of selected mRNAs in biopsies were determined before and after training . VO2 max ( + 5 % ) and Tlim ( + 35 % ) increased specifically in the Hyp group . At the molecular level , mRNA concentrations of the hypoxia-inducible factor 1alpha ( + 104 % ) , glucose transporter-4 ( + 32 % ) , phosphofructokinase ( + 32 % ) , peroxisome proliferator-activated receptor gamma coactivator 1alpha ( + 60 % ) , citrate synthase ( + 28 % ) , cytochrome oxidase 1 ( + 74 % ) and 4 ( + 36 % ) , carbonic anhydrase-3 ( + 74 % ) , and manganese superoxide dismutase ( + 44 % ) were significantly augmented in muscle after exercise training in Hyp only . Significant correlations were noted between muscular mRNA levels of monocarboxylate transporter-1 , carbonic anhydrase-3 , glucose transporter-4 , and Tlim only in the group of athletes who trained in hypoxia ( P < 0.05 ) . Accordingly , the addition of short hypoxic stress to the regular endurance training protocol induces transcriptional adaptations in skeletal muscle of athletic subjects . Expressional adaptations involving redox regulation and glucose uptake are being recognized as a potential molecular pathway , result ing in improved endurance performance in hypoxia-trained subjects Twenty healthy high-altitude natives , residents of La Paz , Bolivia ( 3,600 m ) , participated in 6 wk of endurance exercise training on bicycle ergometers , 5 times/wk , 30 min/session , as previously described in normoxia-trained sea-level natives ( H. Hoppeler , H. Howald , K. E. Conley , S. L. Lindstedt , H. Claassen , P. Vock , and E. R. Weibel . J. Appl . Physiol . 59 : 320 - 327 , 1985 ) . A first group of 10 subjects was trained in chronic hypoxia ( HT ; barometric pressure = 500 mmHg ; inspired O2 fraction = 0.209 ) ; a second group of 10 subjects was trained in acute normoxia ( NT ; barometric pressure = 500 mmHg ; inspired O2 fraction = 0.314 ) . The workloads were adjusted to approximately 70 % of peak O2 consumption ( VO2peak ) measured either in hypoxia for the HT group or in normoxia for the NT group . VO2peak determination and biopsies of the vastus lateralis muscle were taken before and after the training program . VO2peak in the HT group was increased ( 14 % ) in a way similar to that in NT sea-level natives with the same protocol . Moreover , VO2peak in the NT group was not further increased by additional O2 delivery during the training session . HT or NT induced similar increases in muscle capillary-to-fiber ratio ( 26 % ) and capillary density ( 19 % ) as well as in the volume density of total mitochondria and citrate synthase activity ( 45 % ) . It is concluded that high-altitude natives have a reduced capillarity and muscle tissue oxidative capacity ; however , their training response is similar to that of sea-level residents , independent of whether training is carried out in hypobaric hypoxia or hypobaric normoxia BACKGROUND Exercise training improves physical fitness , insulin resistance , and endothelial function in type 2 diabetes . Hypoxia may further optimize these beneficial effects . The aim of this study was to compare the effects of hypoxic versus normoxic exercise training on physical fitness , endothelial function , and insulin resistance in type 2 diabetes . METHODS Peak oxygen consumption , flow mediated dilation ( endothelial function ) , and glucose homeostasis were assessed in 19 patients ( 55±7 years ) before and after an 8-week intervention . Subjects were r and omly allocated to normoxic ( 21 % O2 , n=9 ) or hypoxic ( 16.5 % O2 , n=10 ) exercise training . Endothelium-independent dilation was examined using sublingual administration of glyceryl trinitrate , and used to calculate the ratio between endothelium-dependent and -independent dilation . RESULTS Exercise training  improved physical fitness and brachial artery ratio between endothelium-dependent and -independent dilation ( both p<0.05 ) , whilst these exercise training-induced changes were similar in both groups ( interaction-effects p>0.05 ) . Exercise training did not significantly change brachial artery flow-mediated dilation or glyceryl trinitrate-response , superficial femoral artery flow-mediated dilation , or glucose homeostasis , whilst hypoxia did not alter the impact of exercise training . CONCLUSION Contrary to our hypothesis , hypoxia does not potentiate the effect of exercise training  on physical fitness , vascular function , or glucose homeostasis in type 2 diabetes This study was performed to explore changes in gene expression as a consequence of exercise training at two levels of intensity under normoxic and normobaric hypoxic conditions ( corresponding to an altitude of 3,850 m ) . Four groups of human subjects trained five times a week  for a total of 6 wk on a bicycle ergometer . Muscle biopsies were taken , and performance tests were carried out before and after the training period . Similar increases in maximal O(2 ) uptake ( 8.3 - 13.1 % ) and maximal power output ( 11.4 - 20.8 % ) were found in all groups . RT-PCR revealed elevated mRNA concentrations of the alpha-subunit of hypoxia-inducible factor 1 ( HIF-1 ) after both high- ( + 82.4 % ) and low (+78.4%)-intensity training under hypoxic conditions . The mRNA of HIF-1alpha(736 ) , a splice variant of HIF-1alpha newly detected in human skeletal muscle , was shown to be changed in a similar pattern as HIF-1alpha . Increased mRNA contents of myoglobin ( + 72.2 % ) and vascular endothelial growth factor ( + 52.4 % ) were evoked only after high-intensity training in hypoxia . Augmented mRNA levels of oxidative enzymes , phosphofructokinase , and heat shock protein 70 were found after high-intensity training under both hypoxic and normoxic conditions . Our findings suggest that HIF-1 is specifically involved in the regulation of muscle adaptations after hypoxia training . Fine-tuning of the training response is recognized at the molecular level , and with less sensitivity also at the structural level , but not at global functional responses like maximal O(2 ) uptake or maximal power output Background and Objectives Increased central arterial stiffness is an emerging risk factor for cardiovascular disease . Acute aerobic exercise reduces arterial stiffness , while acute resistance exercise may increase arterial stiffness , but this is not a universal finding . We tested whether an acute resistance exercise program was associated with an increase in arterial stiffness in healthy young men . Subjects and Methods Thirteen healthy subjects were studied under parallel experimental conditions on 2 separate days . The order of experiments was r and omized between resistance exercise ( 8 resistance exercises at 60 % of 1 repeated maximal ) and sham control ( seated rest in the exercise room ) . Carotid-femoral pulse wave velocity ( PWV ) and aortic augmentation index as indices of aortic stiffness were measured using applanation tonometry . Measurements were made at baseline before treatments , 20 minutes , and 40 minutes after treatments ( resistance exercise and sham control ) . Results There was no difference in resting heart rate or in arterial stiffness between the two experimental conditions at baseline . At 20 minutes after resistance exercise , heart rate , carotid-femoral PWV and augmentation index@75(% ) were significantly increased in the resistance exercise group compared with the sham control ( p<0.05 ) . Brachial blood pressure , central blood pressure and pulse pressure were not significantly increased after resistance exercise . Conclusion An acute resistance exercise program can increase arterial stiffness in young healthy men . Further studies are needed to clarify the effects of long-term resistance training on arterial stiffness Background Intermittent normobaric hypoxia training , an alternative to altitude training for athletes , may be beneficial to treat overweight and obesity . The purpose of this study is to investigate whether normobaric hypoxia training combined with low-caloric diet has the additive effect on weight loss compared with normoxia training in obese young adults . Methods Twenty-two subjects ( age 17–2 
    Output:
    
Conclusion Based on current published studies , hypoxic ExT potentiates vascular adaptations related to skeletal muscle capillarization and dilator function .
These findings may contribute to establishing effective exercise programs design ed to enhance vascular health