In search of light therapy to optimize the internal clock, performance and sleep
| PhD ceremony: | Ms M. Geerdink |
| When: | September 29, 2017 |
| Start: | 14:30 |
| Supervisors: | prof. dr. D.G.M. Beersma, prof. dr. R.A. (Roelof) Hut |
| Co-supervisor: | dr. M.C.M. (Marijke) Gordijn, PhD |
| Where: | Academy building RUG |
| Faculty: | Science and Engineering |
Light is not only crucial for vision, but also important to optimize the biological clock, sleep and well-being. Without sufficient light, the biological clock in our brain will run out of sync with daily life and as a consequence, our performance and sleep will become worse. Despite this fact, sleeping out of phase with the daily light-dark cycle, especially sleeping later, has become a common habit in our society. As a result of the discrepancy in sleep timing on workdays and free days, many people experience a so-called weekly ‘social jetlag’.
One way to adjust ourselves to earlier bedtimes, is by adjusting the biological clock to an earlier phase. Use of light and darkness at the right moment seems the key to achieve this goal. Although lighttherapy is indeed already a popular tool, it is not clear how it can be used optimally. The time to ‘see’ the light, the duration and colour are important aspects that needs optimization.
In our ‘home’-studies it became clear that ideally timed short light pulses of 30 minutes with the right color were able to shift the biological clock of late sleepers. Sleep quality and performance were kept stable, while it decreased when the wrong colour of light was used. In our ‘lab’ study it was found that more light during the working day is able to improve sleep quality the subsequent night. The most important conclusions: Extra light can improve sleep and performance, provided it is the right light at the right moment.