The lighting  is an important part of the environment that either support or disturb patients health and recovery.

The daylight and lighting, good used, synchronise the human circadian rhythm. Here the sleep and wake rhythm are the most evident rhythm. Patients at the ICU often suffer from disturbed sleep, circadian rhythm and risk for delirium.

In an attempt to support the patient's circadian rhythm and health, a lighting intervention was set up in the patients' room. This was an automatic controlled lighting system which tried to mimic the natural day light in its position, brightness and colour of light.

Patients were asked in questionnaires and in interviews about their experiences about the lighting environment. Most of them were pleased about the lighting. It was a good uplifting light that supported their circadian rhythm.