title: Dyspnea ratings for prescription of cross-modal exercise in patients with COPD.
abstract: OBJECTIVE
  To investigate the ability of patients with COPD to reproduce an exercise intensity accurately on the treadmill using dyspnea ratings obtained during incremental exercise on the cycle ergometer (cross-modal exercise prescription).
  
  
  METHODS
  Five visits over an 8-week period.
  
  
  METHODS
  Thirteen symptomatic patients with stable COPD. Age was 67+/-6 years (mean+/-SD). FEV1 was 1.15+/-0.22 L (45+/-7% predicted).
  
  
  METHODS
  At each visit, patients performed spirometry and exercise. Visit 1 was a practice incremental exercise test on the cycle ergometer. At visit 2 (1 week later), patients estimated the intensity of dyspnea using the 0 to 10 category-ratio scale during an incremental exercise test on the cycle ergometer (cycle estimation trial). Visit 3, 5 weeks later, was a practice session on the treadmill. At visit 4, 1 week later, patients were instructed to produce specific intensities of dyspnea (ie, dyspnea targets) at 50% and at anaerobic threshold (AT) or 80% of peak oxygen consumption (VO2) as calculated from results at visit 2 (treadmill production trial). Visit 5, 1 week later, was the treadmill estimation trial.
  
  
  RESULTS
  Lung function was stable at all visits. Dyspnea ratings were 1.9+/-0.9 at 50% of VO2 and 5.6+/-1.5 at AT/80% of peak VO2 (17.5+/-3.3 mL/kg/min). The VO2 at the treadmill production trial (761+/-185 mL/min) was significantly higher than at the cycle estimation trial (612+/-159 mL/min) at the low dyspnea target (p < 0.0002; upward bias, 26+/-16%). In contrast, there was no significant difference in VO2 values (929+/-176 mL/min vs 948+/-259 mL/min) at the high dyspnea target (p > 0.5; 0+/-11% bias).
  
  
  CONCLUSIONS
  Patients with COPD can use dyspnea ratings from an incremental cycle ergometry test to regulate exercise on the treadmill without systematic bias at an intensity of 80% of peak VO2, but exceed the desired VO2 when using the dyspnea rating at an intensity of 50% of peak VO2.
authors.affiliation: Section of Pulmonary and Critical Care Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756-0001, USA.
authors.forename: M B
authors.initials: MB
authors.lastname: Horowitz
authors.forename: D A
authors.initials: DA
authors.lastname: Mahler
mesh_terms: D000368:Aged; D001945:Breathing Exercises; D004417:Dyspnea / Q000175:diagnosis / Q000503:physiopathology*; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000503:physiopathology* / Q000628:therapy; D008297:Male; D010045:Outpatients; D011237:Predictive Value of Tests; D055656:Prescriptions; D012044:Regression Analysis; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D013147:Spirometry