People who go to bed at regular hour but wake up too early for their taste, are called early morning awakening insomnia.
The theory, if I am not mistaken, is that the early morning awakening insomnia people's body temperature graph and consequently their melatoning levels graph is flat, i.e. the difference between high peaks and low peaks is too low, therefore they either don't sleep deep or don't sleep long enough or both.
In this experiment they are trying to increase the difference between high and low by applying bright light therapy in the evening, just before going to sleep. Hm...
Past studies have predicted that early morning awakening insomnia is associated with advanced or early circadian rhythms.
Because bright light stimulation in the evening can delay the phase of circadian rhythms, we tested its effects on nine (4 females, 5 males) early morning awakening insomniacs.
Their sleep was evaluated and their temperature and melatonin circadian rhythms were measured.
In the initial evaluation, the temperature rhythm phase positions of these insomniacs did appear to be earlier than normal. The subjects were then exposed to bright light stimulation (2,500 lux) from 8 pm to midnight on two consecutive evenings. Following the evening bright light treatment, temperature rhythm phase markers were delayed 2-4 hours and melatonin phase markers were delayed 1-2 hours.
Sleep onset times were not changed but the mean final wake-up time was delayed from 5 am hours to six am, resulting in a mean increase of total sleep time of one hour.
This pilot study suggests that evening bright light stimulation may be an effective nondrug treatment for early morning awakening insomnia.
I wonder if sufficient high intensity light (sunlight) and maybe some exercise could produce the same results.
Early waking insomnia people are normally older people, who probably don't spend any time moving around and outside.
I'll do some more research and let you know what I find.