The study lasts for 19 months and contains 7 visits. After the screening visit at the Centre for Chronobiology, Basel, Switzerland, participants are assigned to either the intervention or the control group which is followed by a 7-day baseline week at home and a co-design meeting to provide instructions to the intervention and the control group. At the occasion of 4 visits (spread over 12 months) at the participants' homes, different measurements will be performed such as saliva collection, questionnaires, cognitive performance tests, light and rest-activity measures. A follow-up visit 6 months after completion of the last data collection will provide qualitative feedback by the participants.
The main objective of the study is to improve subjective sleep quality using a multimodal intervention with an intervention and a control group. The multimodal intervention aims to improve circadian Zeitgeber strength. This will be achieved by optimizing daily light exposure, sleep, physical activity, and mealtimes.