Introduction: Chronic obstructive airway disease (COPD) is common condition in old age and the perception of hypoxia is often impaired in some COPD patients. Therefor it is need to monitor oxygen saturation in older people with COPD. A finger wearable device has been developed to measure oxygen saturation and heart rate variability. The investigators therefore will perform a cross sectional study to evaluate the clinical application of this finger wearable device in the detection and management of COPD in older people.