But it may be that the most important aspect of sleep hygiene has to do with light I'm not convinced.
The most important thing for sleep is your eating habits - if you want to wake up early eat very early dinners. If you want to wake up at 8 am, your last meal of the day should be at 6 pm (14 hours before that).
This works so well, that it overrides the effects of alcohol and caffeine and often even how tired you are. Even if you usually stay up until 3 am you'll get very sleepy at midnight and you'll wake up at 8. If fact even if you are prevented from sleeping until 3, you'll still wake up at 8 after just 5 hours of sleep. Have a full breakfast to avoid sleeping during the day - the next day you'll probably get sleepy at midnight again, even if you have dinner a bit later than 6.
Why does this work? Your 'food clock' will override all the other timers that govern your sleep habits. I cannot find the sources for this, but there are pretty good biological reasons this works. I know that I have used this rule many times for my benefit when working shift work or travelling or even getting back in rhythm after a vacation.
Apparently you can use a similar trick to overcome jetlag by fasting. One of those articles might have more information about the 'food clock' overriding other timers.
Though personally, I find the biggest difference in being able to sleep comes from avoiding screens and reading a book (or eink) instead.
Would it be safe to assume that reading from a Kindle Paperwhite with the backlight on is closer to being a screen than a book? I read mine very regularly at night and wonder if it's more effective to keep a lamp on and read with the backlight off (as opposed to reading in the dark with the backlight on and heavily dimmed).
I'm honestly not sure -and I'm still using an original nook, so don't even have first hand anecdotal evidence.
I believe the issue is the frequency of light -computer screens tend to be on the bluer/whiter end of the spectrum -in fact if you look at apps like f-lux they try and help by changing your screen to be much more red; I'd also say that a monitor/tv is putting out substantially more light than your kindle. I'm also now wondering about the difference between looking directly at a lightsource (or reading from a backlit source) compared to indirect lighting; but once again I have neither the knowledge or references.
edit: (as I can't edit my original comment) I've just realised that I never mentioned suffering with extreme acid reflux so being hungry/empty stomach isn't really an option for me -and certainly stops me sleeping, which might well have a bearing on my anecdotal observations in the OP.
The question is about falling asleep, rather than waking up early right? Waking up early is simply a question of alarms/light/whatever.
Eating early will have no measurable impact on the ability to "wind down" and sleep as far as I can see, nor does that link seem to support it?
I can pretty much always sleep (I'm lucky) and I go to bed late (I'm dumb and play too much dota) - so I struggle with the waking up thing. This is despite not really eating in the evenings. Anecdotally I'm just saying I don't think there's one most important thing - just a set of factors and decisions which have an impact.
If the 'food clock' exists, there is a good chance that it works by inhibiting the circadian alertness signal, thus making the body feel more sleepy on net, until the alertness level rises again naturally.
It is an interesting question (so I up-voted it), but they are not conflicting since it doesn't happen at the some.
I don't think it is really food deprivation - any healthy human being should be able to go 16 hours between meals once in a while (assuming regular meals most of the time). When you wake up you do wake up hungry, but you don't feel impaired yet.
Food deprivation may start after that - so you might get lethargic and sleepy because of it.
It seems more like "Having food in you keeps you awake" - so a big breakfast will keep you running until the afternoon, and an early dinner will mean the tanks less full when you want to sleep.
I believe that the large meal effect has an impact on how easy it is to wake up, but little effect on how hard it is to fall asleep, at least for me.
Or it could just be that everybody's different.
It's a very common pattern in rural areas to have a quick nap after large meals. It's mostly done because exercise on a full stomach is a bad idea, but it's also done because the heavy meal makes it easier to fall asleep. We're all familiar with the "thanksgiving turkey effect", which has very little to do with tryptophan and lots to do with the large meal.
Personally, I can fall asleep quickly if these conditions are met:
- no caffeine within the last 8-12 hours.
- one hour since last significant blue screen exposure
- my mind is calm
- I'm not over-tired
Large meals do not appear to have any impact on me.
The last two may be the same effect; I find it difficult to calm myself when I'm overtired.
Eating a full breakfast in order to avoid sleeping during the day might be an excellent advice to those that got a healthy digestion, healthy sugar levels and in general are a person in good health.
Having 5 meals per day, eating at 6 means for me falling asleep at 9, because at 10 I get hungry again and due to that hunger going to sleep afterwards becomes a nightmare. It's hard for me to imagine getting myself to fall asleep at 3 am in this condition!
I long to be able to turn in at 10 pm, but our household has for many years tended toward late dinner times (8:30 or 9 pm). But once it is daylight, I wake up. On weekends I might be able to manage an extra hour or two of interrupted sleep.
The most important thing for sleep is your eating habits - if you want to wake up early eat very early dinners. If you want to wake up at 8 am, your last meal of the day should be at 6 pm (14 hours before that).
This works so well, that it overrides the effects of alcohol and caffeine and often even how tired you are. Even if you usually stay up until 3 am you'll get very sleepy at midnight and you'll wake up at 8. If fact even if you are prevented from sleeping until 3, you'll still wake up at 8 after just 5 hours of sleep. Have a full breakfast to avoid sleeping during the day - the next day you'll probably get sleepy at midnight again, even if you have dinner a bit later than 6.
Why does this work? Your 'food clock' will override all the other timers that govern your sleep habits. I cannot find the sources for this, but there are pretty good biological reasons this works. I know that I have used this rule many times for my benefit when working shift work or travelling or even getting back in rhythm after a vacation.
Edit: http://news.bbc.co.uk/2/hi/health/7414437.stm - I've added this report from the BBC as a source. I've used 14 hours instead of 16 but I find it works about the same for me.