Advantages of endurance treadmill walking compared with cycling to assess bronchodilator therapy.
BACKGROUND
Walking is a familiar daily activity that is generally limited by breathlessness, whereas cycling is an uncommon physical effort typically limited by leg discomfort. The hypothesis was that patients with COPD would exhibit greater improvements in exercise endurance and relief of breathlessness with bronchodilator therapy during treadmill walking compared with cycling.


METHODS
In this randomized, 2 x 2, double-blind, placebo-controlled, crossover trial, 20 patients with COPD (age, 64 +/- 7 years; FEV(1), 56 +/- 14% predicted) performed constant-load endurance exercise on the treadmill and cycle ergometer at 85% of capacity after inhaling normal saline (NS) or arformoterol (ARF) (15 microg).


RESULTS
Increases in endurance times and consistency of responses were greater with treadmill walking (Delta: 157 +/- 286 s; P = .024; 80% improved) than with cycle exercise (Delta: 110 +/- 219 s; P = .038; 65% improved) with ARF compared with NS. However, these changes were not significantly different. The slope of breathlessness-time (mean Delta = -29%; P = .007) and the magnitude of oxygen desaturation were significantly lower with ARF compared with NS during treadmill, but not cycle, exercise. Inspiratory capacity values were similar between modes of exercise when comparing the same study medication.


CONCLUSIONS
Improved endurance times support both constant-load treadmill and cycle exercise to assess the efficacy of bronchodilator therapy in patients with COPD. Unique differences in physiologic and perceptual responses with bronchodilation demonstrate advantages of treadmill walking as an exercise stimulus.


BACKGROUND
clinicaltrials.gov; Identifier: NCT00754546.
Zhang
Xiaolei
X
Pulmonary and Critical Care Medicine, Dartmouth-Hitchcock Medical Center, 1 Medical Center Dr, Lebanon, NH 03756-0001, USA.
Waterman
Laurie A
LA
Ward
Joseph
J
Baird
John C
JC
Mahler
Donald A
DA
D000704:Analysis of Variance; D001642:Bicycling / Q000502:physiology*; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004417:Dyspnea / Q000188:drug therapy* / Q000503:physiopathology*; D004983:Ethanolamines / Q000627:therapeutic use*; D005080:Exercise Test; D005260:Female; D000068759:Formoterol Fumarate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance / Q000187:drug effects* / Q000502:physiology*; D010919:Placebos; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy* / Q000503:physiopathology*; D012129:Respiratory Function Tests; D013147:Spirometry; D016896:Treatment Outcome; D016138:Walking / Q000502:physiology*
D001993:Bronchodilator Agents; D004983:Ethanolamines; D010919:Placebos; D000068759:Formoterol Fumarate