[Physiologic responses to walking and cycling in patients with chronic bronchial obstruction]

In patients with bronchial obstruction, desaturation is more important during walking than cycling. For other effort parameters, studies report conflicting data.

Comparing different responses (desaturation, tachycardia, tachypnea, dyspnea) to the 6 minutes walking test (WT6) and to cycling at 25 watts for 10 minutes (CT) in patients with COPD or asthma and assessing the correlation between these responses and functional parameters at rest.

15 patients with moderate to severe COPD (FEVI = 49,8 +/- 16%) and 13 patients with stable occupational asthma (FEVI = 75,5 +/- 26%) were evaluated by: resting spyrogram, the Saint George Respiratory Questionnaire, dyspnea (the MMRC scale), the Dijon activity score, WT6 and CT with monitoring of the arterial oxygen saturation and of the heart rate (PulsiQuant-ENVITEC-Wismar oxymeter) and with the assessment of effort-induced dyspnea using the modified Borg scale. During the 2 exercise tests, pulsoxymetry, thoracic movements and nasal airflow were concomitantly assessed using a portable cardio-respiratory polygraph (Stardust-Respironics).

Walking distance correlated moderately with spyrographic parameters (r = 0,54 for FEV1), strongly with the Dijon activity score (r = 0,75) and there was a strong negative correlation with the acute Borg dyspnea (r = -0,83) and with the chronic MMRC dyspnea (r = -0,71). The mean and the minimum saturations were lower for the WT6 than for the CT (p = 0,019 and p<0,01, respectively). The mean and the maximal heart rates were lower for the CT than for the WT6 (p = 0,021 andp = 0,024, respectively). The acute Borg dyspnea was higher during walking than cycling (p

Walking distance strongly correlated with the level of physical activity and inversely with effort-induced dyspnea. Walking was more stressful than cycling, from the point of view of effort-induced desaturation, dyspnea, tachycardia and tachypnea.