Characteristics before each randomised intervention treadmill test in 17 patients with moderate to severe chronic obstructive pulmonary disease

Intervention arm
Central and peripheral endogenous endorphins (normal saline)Central endogenous endorphins only (methylnaltrexone)No endogenous endorphins (naloxone)
Subjects n171616
  % pred53.95±17.6656.16±18.0552.94±17.82
  % pred56.28±18.1656.58±16.9356.53±18.27
Mean FVC
 % pred72.95±11.7777.107±11.1773.89±11.34
Post-bronchodilator FEV1/FVC0.55±0.160.56±0.180.55±0.17

Data are presented as n or mean±sd. FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity.