Apparatus for transcutaneous electrical nerve stimulation in a user, the apparatus comprising: a housing; stimulation means for electrically stimulating at least one nerve; an electrode releasably mounted to the housing and connectable to the stimulation means for electrical stimulation of the at least one nerve; monitoring means for monitoring the user's body orientation and movement; analysis means for analyzing said orientation and movement; and control means for controlling the output of the stimulation means in response to said analysis of said orientation and movement.