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 .
Skeletal muscle adaptations to interval training in patients with advanced COPD.
STUDY OBJECTIVES To investigate the response to interval exercise ( IE ) training by looking at changes in morphologic and biochemical characteristics of the vastus lateralis muscle , and to compare these changes to those incurred after constant-load exercise ( CLE ) training . DESIGN R and omized , controlled , parallel , two-group study ( IE vs CLE training ) . SETTING Multidisciplinary , outpatient , hospital-based , pulmonary rehabilitation program . PATIENTS Nineteen patients with stable advanced COPD ( mean + /- SEM FEV1 , 40 + /- 4 % predicted ) . INTERVENTIONS Patients ( n = 10 ) assigned to IE training exercised at a mean intensity of 124 + /- 15 % of baseline peak exercise capacity ( peak work rate [ Wpeak ] ) with 30-s work periods interspersed with 30-s rest periods for 45 min/d . Patients ( n = 9 ) allocated to CLE training exercised at a mean intensity of 75 + /- 5 % Wpeak for 30 min/d . Patients exercised 3 d/wk for 10 weeks . MEASUREMENTS AND RESULTS Needle biopsies of the right vastus lateralis muscle were performed before and after rehabilitation . After IE training , the cross-sectional areas of type I and IIa fibers were significantly increased ( type I before , 3,972 + /- 455 microm2 ; after , 4,934 + /- 467 microm2 [ p = 0.004 ] ; type IIa before , 3,695 + /- 372 microm2 ; after , 4,486 + /- 346 microm2 [ p = 0.008 ] ) , whereas the capillary-to-fiber ratio was significantly enlarged ( from 1.13 + /- 0.08 to 1.24 + /- 0.07 [ p = 0.013 ] ) . Citrate synthase activity increased ( from 14.3 + /- 1.4 to 20.5 + /- 4.2 micromol/min/g ) , albeit not significantly ( p = 0.097 ) . There was also a significant improvement in Wpeak ( by 19 + /- 5 % ; p = 0.04 ) and in lactate threshold ( by 17 + /- 5 % ; p = 0.02 ) . The magnitude of changes in all the above variables was not significantly different compared to that incurred after CLE training . During training sessions , however , ratings of dyspnea and leg discomfort , expressed as fraction of values achieved at baseline Wpeak , were significantly lower ( p < 0.05 ) for IE training ( 73 + /- 9 % and 60 + /- 8 % , respectively ) compared to CLE training ( 83 + /- 10 % and 87 + /- 13 % , respectively ) . CONCLUSIONS High-intensity IE training is equally effective to moderately intense CLE training in inducing peripheral muscle adaptations ; however , IE is associated with fewer training symptoms
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 .