Article

This study investigated whether different breathing conditions during exercise
testing will influence measures of exercise capacity commonly used for training
prescription in chronic obstructive pulmonary disease. Twenty-seven patients with
chronic obstructive pulmonary disease (forced expiratory volume in 1 sec = 45.6
[9.4]%) performed three maximal exercise tests within 8 days, but at least 48 hrs
apart. Subjects were thereby breathing either room air through a tightly fitting
face mask like during any cardiopulmonary exercise test (MASK), room air without
mask (No-MASK), or 10 l/min of oxygen via nasal cannula (No-MASK + O2). Cycling
protocols were identical for all tests (start = 20 watts, increment = 10 males/5
females watts/min). Maximal work rate (90.4 [33.8], 100.3 [34.8], 107.4 [35.9]
watts, P < 0.001) and blood lactate at exhaustion (4.3 [1.5], 5.2 [1.6], 5.0
[1.4] mmol/l, P < 0.001) were lowest for MASK when compared with No-MASK and
No-MASK + O2, respectively, whereas maximal heart rate did not differ
significantly. Submaximal exertion (Borg rating of perceived exertion = 12-14)
was perceived at lower intensity (P = 0.008), but higher heart rate (P = 0.005)
when MASK was compared with No-MASK and No-MASK + O2. Different breathing
conditions during exercise testing resulted in an 18.8% difference in maximal
work rate, likely causing underdosing or overdosing of exercise in chronic
obstructive pulmonary disease. Face masks reduced whereas supplemental oxygen
increased patients' exercise capacity. For accurate prescription of exercise in
chronic obstructive pulmonary disease, breathing conditions during testing should
closely match training conditions.

Langue : ANGLAIS