According to an example embodiment, a lighting controller for controlling light output from one or more luminaires provided for illuminating a space is provided. The lighting controller is arranged to control the light output in accordance with a default lighting schedule that defines respective predefined durations for a sequence of alternating working periods and breaks, where the duration defined for a break in relation to the duration defined for the immediately preceding working period of the sequence increases over time, wherein the lighting controller is arranged to change at least one characteristic of the light output of the one or more luminaires upon the default lighting schedule indicating a transition from a working period to a break and upon the default lighting schedule indicating a transition from a break to a working period.
