Lack of Ventilatory Threshold in Patients with Chronic Obstructive Pulmonary Disease

Jun Midorikawa, Wataru Hida, Osamu Taguchi, Shinichi Okabe, Hajime Kurosawa, Akiko Mizusawa, Hiromasa Ogawa, Satoru Ebihara, Yoshihiro Kikuchi, Kunio Shirato

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

We investigated whether the ventilatory threshold (VET) could be detected in 25 patients with severe chronic obstructive pulmonary disease (COPD). Exercise on a treadmill was performed until symptom-limited maximum oxygen uptake (VO2SL) was obtained. VET was absent in 14 patients (56%, VET(-) group) and present in the others (44%, VET(+) group). Basal pulmonary functions and dyspnea index (VE, SL/MVV) were not different between the two groups. Endurance time and exercise tolerance (VO2SL/bw) were significantly less in VET(-) than in VET(+). In the former group, Pao2 and pH at maximal exercise decreased and Paco2 increased significantly, but HCO3 did not change compared with the corresponding values before exercise. In the latter group, Paco2 at maximal exercise increased significantly, and pH and HCO3 decreased significantly compared with the values before exercise, but Pao2 did not. The changes in Pao2 and Paco2 were not different between the two groups, but changes in pH and HCO3 in VET(+) were greater than those in VET(-). These results suggest that the absence of VET in some COPD patients indicates a lower exercise capacity without producing metabolic acidosis. This may be caused by rapidly developing dyspnea.

Original languageEnglish
Pages (from-to)76-80
Number of pages5
JournalRespiration
Volume64
Issue number1
DOIs
Publication statusPublished - 1997 Jan 1

Keywords

  • Anaerobic threshold
  • Difficulty in breathing
  • Exercise tolerance
  • Oxygen uptake
  • Treadmill

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine

Fingerprint

Dive into the research topics of 'Lack of Ventilatory Threshold in Patients with Chronic Obstructive Pulmonary Disease'. Together they form a unique fingerprint.

Cite this