***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: AIMS Patients with chronic heart failure ( CHF ) exhibit detrimental changes in skeletal muscle that contribute to their impaired physical performance . This study investigates the possibility of counteracting these changes by chronic low-frequency electrical stimulation ( CLFS ) of left and right thigh muscles . METHODS AND RESULTS ( mean+/-SD ) 32 CHF patients ( 53+/-10 years ) with an LVEF of 22+/-5 % , NYHA II-IV , undergoing optimized drug therapy , were r and omized in a CLFS group ( CLFSG ) or a control group ( controls ) . The groups differed in terms of the intensity of stimulation , which elicited strong muscle contractions only in the CLFSG , whereas the controls received current input up to the sensory threshold without muscle contractions . Functional capacity was assessed by peak VO(2 ) , work capacity , and a 6-min-walk ( 6-MW ) . Muscle biopsies were analyzed for myosin heavy chain ( MHC ) isoforms , citrate synthase ( CS ) and glyceraldehydephosphate dehydrogenase ( GAPDH ) activities . Peak VO(2)(mlmin(-1)kg -1 ) increased from 9.6+/-3.5 to 11.6+/-2.8 ( P<0.001 ) in the CLFSG , and decreased from 10.6+/-2.8 to 9.4+/-3.2 ( P<0.05 ) in the controls . The increase in the CLFSG was paralleled by increases in maximal workload ( P<0.05 ) and oxygen uptake at the anaerobic threshold ( P<0.01 ) . The corresponding values of the controls were unchanged , as also the 6-MW values , the MHC isoform distribution , and both CS and GAPDH activities . In the CLFSG , the 6-MW values increased ( P<0.001 ) , CS activity was elevated ( P<0.05 ) , GAPDH activity decreased ( P<0.01 ) , and the MHC isoforms were shifted in the slow direction with increases in MHCI at the expense of MHCIId/x ( P<0.01 ) . CONCLUSIONS Our results suggest that CLFS is a suitable treatment to counteract detrimental changes in skeletal muscle and to increase exercise capacity in patients with severe CHF OBJECTIVE Inflammation has been found to play a role in the etiology of cardiovascular disease as well as provoke endothelial dysfunction . Inflammatory cytokines associated with endothelial function are interleukin-6 ( IL-6 ) and tumor necrosis factor-alpha ( TNF-alpha ) . IL-6 is exercise intensity dependent and has been shown to inhibit TNF-alpha expression directly . The aim of this study was to investigate the interaction of IL-6 and TNF-alpha on endothelial function in response to acute exercise in overweight men exhibiting different physical activity profiles . METHODS AND PROCEDURES Using a r and omized mixed factorial design , 16 overweight men ( 8 active , maximal exercise capacity ( VO(2)peak ) = 34.2 + /- 1.7 , BMI = 27.4 + /- 0.7 and 8 inactive , VO(2)peak = 30.9 + /- 1.2 , BMI = 29.3 + /- 1.0 ) performed three different intensity acute exercise treatments .  Brachial artery flow-mediated dilation ( FMD ) and subsequent blood sample s were taken pre-exercise and 1 h following the cessation of exercise . RESULTS Independent of exercise intensity , the active group displayed a 24 % increase ( P = 0.034 ) in FMD following acute exercise compared to a 32 % decrease ( P = 0.010 ) in the inactive group . Elevated ( P < 0.001 ) concentrations of IL-6 following moderate ( 50 % VO(2 ) ) and high ( 75 % VO(2 ) ) intensity acute exercise were observed in both groups ; however , concentrations of TNF-alpha were unchanged in response to acute exercise ( P = 0.584 ) . DISCUSSION The FMD response to acute exercise is enhanced in active men who are overweight , whereas inactive men who are overweight exhibit an attenuated response . The interaction of IL-6 and TNF-alpha did not provide insight into the physiological mechanisms associated with the disparity of FMD observed between groups 
    Output:
    
In addition to the patients with comorbidities , it is unlikely that AMI patients suffering from cardiac instability , who are obliged to have bed rest , will perform conventional exercise training .
Nevertheless , even low-intensity resistance muscle training could be a burden for patients with cardiovascular instability .
Functional electrical stimulation or neuromuscular electrical stimulation ( NMES ) of muscles is expected to be an alternative mode of rehabilitation for AMI patients who are intolerant to conventional exercise training .
A meta- analysis of r and omized , controlled trials in CHF patients comparing NMES with conventional exercise training showed that conventional cycle training produced superior improvements in exercise capacity to that of NMES .
Also , compared with NMES therapy , conventional exercise training is more simple and practical in that no special apparatus is needed .
Therefore , the introduction of NMES is expected to raise the implementation rate of CR in patients who are intolerant of exercise training .