Efficacy of timed bright light exposure and physical activity in the treatment of Delayed Sleep Phase Disorder

Delayed Sleep Phase Disorder (DSPD) is a circadian rhythm disorder
characterized by a chronically delayed sleep-wake rhythm. This results in
inabilities to fall asleep and difficulties waking-up at socially desired
times, which largely affects daily functioning of DSPD patients. Treatment of
DSPD aims to phase advance the circadian clock by application of external time
cues. Morning light is the most important signal for daily synchronisation of
the circadian clock to the environment. Light during the evening and night
disrupts the circadian clock. Apart from light, the circadian clock was found
to be directly responsive to physical exercise. However, little research has
been done on the impact of daily physical activity on circadian rhythms in
clinical practice.

The main objective is to determine whether a 5-day intervention of daily timed
physical exercise improves sleep parameters and is capable of resetting the
circadian clock in patients with DSPD. The secondary objectives are to compare
the efficacy of physical activity to that of daily light therapy and to test
whether mood and attention are affected by interventions of light exposure and
physical activity.

randomized placebo-controlled intervention study.

group 1: morning bright light therapy (30 min, 10.000 lux)
group 2: physical activity for 30 minutes (70% VO2max)
group 3: the placebo group, morning red dim light without physical activity (30
min).

Participating in this study is at low risk since the investigational treatment
does not involve any invasive procedures or medicinal products. The bright
light intensities are comparable to daylight intensities and do not contain UV
light. The level and duration of physical activity is within the range of the
Dutch recommendations for daily physical activity and will be adjusted to the
individual*s VO2 max. While there is a marked burden for participants
particularly in terms of time, participation is aimed to have clear therapeutic
benefit for the patients. The burden consists of: wearing an Actiwatch and
completing a sleep diary during 7 weeks, staying overnight in the hospital
during the 5-day intervention period, collecting hourly saliva samples on the
first and last day of the intervention period (total number of samples = 26),
wearing skin temperature sensors, filling in multiple types of questionnaires
and performing an attention task daily during the 5-day intervention period.