Not eating for 12-16 hours can help people quickly reset their sleep-wake cycle, according to a study from the Harvard Medical School.
http://www.wisebread.com/how-to-naturally-reset-your-sleep-cycle-overnight
Humans average about four or five complete sleep cycles each night, each one lasting about 90 minutes. Dogs, on the other hand, may go through as many as 20 or more complete cycles, each one lasting just 15 minutes or so. Wakefulness between cycles is common in both species.
http://www.doggies.com/articles/243-canine-sleep-cycles.html
Interesting article on how to reset your body clock by tuning in to your food clock. Fasting for 12-16 hours could be a bit tedious on a long haul flight. But i guess if it works, it could be worthwhile giving it a go.
http://www.wisebread.com/how-to-naturally-reset-your-sleep-cycle-overnight
Though rat sleep hours vary, a typical rat sleeps for 20 hours out of 24 (in captivity). A dog sleeps 12-14 hours per day; a lion 13-20 hours; a chimpmunk 15; an elephant 3; a deer also 3. As you can see, interspecies sleep pattern comparisons make little sense.
http://www.wisebread.com/how-to-naturally-reset-your-sleep-cycle-overnight
The first REM sleep period usually occurs about 70 to 90 minutes after we fall asleep. A complete sleep cycle takes 90 to 110 minutes on average. The first sleep cycles each night contain relatively short REM periods and long periods of deep sleep.
https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Understanding-Sleep
Understand characteristics of the normal sleep cycle, including sleep stages, and changes with aging. 2. For sleep disorders, categorize as hypersomnia, insomnia, parasomnia; for each disorder describe major clinical. and physiological characteristics, and mechanisms if known. NORMAL SLEEP PATTERNS.
http://learn.chm.msu.edu/NeuroEd/neurobiology_disease/content/otheresources/sleepdisorders.pdf
When to take: Depending on the severity of the sleep problem, take time-released melatonin 1 to 3 hours prior to the time you usually fall asleep. Since time release melatonin only lasts for 3 – 4 hours, any need to shift sleep schedules more than 3 hours may require taking another pill in 3 or 4 hours. Cautions: Melatonin should not be taken if eyes are exposed to bright sunlight, and melatonin should be avoided if operating any vehicle.
http://www.talkaboutsleep.com/how-to-use-melatonin-correctly/
Puppies and senior dogs tend to sleep more than dogs in the prime of their lives. And dogs who are very active, such as those who herd sheep, will sleep less than a sedentary pet. Most dogs sleep somewhere between 12 and 18 hours each day. If they're bored, they may sleep longer simply to escape the tedium.
http://www.doggies.com/articles/243-canine-sleep-cycles.html
Healthy Aging. There are five phases of sleep: stages 1, 2, 3, 4 and REM (rapid eye movement). Usually when you are sleeping, you begin at stage 1 and go through each stage until reaching REM sleep, and then you begin the cycle again. Each complete sleep cycle takes from 90 to 110 minutes. Your brain acts differently in each stage of sleep.
https://www.verywell.com/the-stages-of-sleep-2224272
Mistake #6: The dosage amount isn’t important. The problem with melatonin is that it was discovered long before scientists really understood what it does and how much you need. For example, in the late 80’s and early 90’s, we thought melatonin was a sleep hormone.
http://www.talkaboutsleep.com/how-to-use-melatonin-correctly/
how long does it take to normalize sleep cycle
It takes 12 to 16 hours to normalize sleep cycle.