Lactate Production During Inspiratory Threshold Loading in COPD

Abstract

The anaerobic threshold has been used as a marker to identify optimal work load for whole body endurance training. To date there has been no convincing evidence of significant anaerobic metabolism during inspiratory muscle training in COPD. Its absence suggests (a) training loads may have been inadequate; or (b) inspiratory muscles produce insufficient lactate to be detected. We examined the relationship between inspiratory load and arterial blood lactate concentration ([La]) during progressive inspiratory threshold loading (PTL) before and after an 8 week program of high intensity inspiratory threshold training in seven COPD patients (FEV1<53% predicted). During PTL, load was increased by 10cm H2O/minute until exhaustion. [La] was measured at the end of each load via a radial arterial catheter.