A monitoring device detects breathing sounds of a user via microphone 18 along with environmental data such as humidity or temperature 20, noise or ambient light 22. Patterns of sleep stages are determined from the breathing sounds, correlation to environmental data being able to help the user to adjust the environment, improving sleep quality. The device may be in the form of a lamp (2, figure 1) on a bedside table, possibly having one or more RGBW LED strips 34, blue LEDs of which may be varied independently of the others because of the link with melatonin levels. The blue light emitted may be in response to the users circadian rhythm using the determined sleep statistics. The monitor may be a smart device wirelessly communicating 16 to a mobile telephone having an app to process the method described, and e.g. a smart thermostat to control temperature settings.
