One of the references in this paper focuses on single sleep deprivation events of a more extreme nature, 48 hours.

As I have experienced when regularly (but not often) working a 36-hour day, I wouldn't do it if it wasn't proven to be well within reach, but it's no breeze if you are the least bit tired and not fully prepared beforehand, especially when it comes to nutrition and not having anything toxic in your system.

This is completely different than regularly losing sleep every night in a habitual way, which could also be considered somewhat along the lines of everyday exposure to toxic materials, whether toxins enter the body intentionally or not.

Don't ask me how I know what it feels like when exposure to different milligrams of different pure industrial chemicals having known toxicity occurs in spite of state-of-the art workplace controls and PPE. I've been working these truly chemical labs all my life. Eventually I felt like I was guinea-pigging caffeine too, and it's old as the hills.

The default in many cultures is to be born into a caffeine-addicted society, steeped in excess habitual ritual in a way which encourages never-ending tradition. This is over and above the physical & emotional habit-forming nature of the drug itself.

Anyway, culture can be real strong, and I enjoyed being a caffeine addict. It actually takes quite a bit of effort if you want to completely withdraw from its pervasive and widespread exposure, whether commercial influence is involved or not. It's everywhere.

With everyday use you build up a tolerance like anything else, and in the long run it really doesn't make a difference whether you lose an hour of sleep every night or get an extra hour, you always feel the same and have the same energy so it must be working, right? Maybe that's supposed to be a red flag.

Now when you're actually a pretty good addict, you never overdo it, you're never jittery or considered extreme like a 20-cup-a-day habit which can't be that bad either when so many of them seem to do just fine.

But way below any extreme consumption, you can still end up with a fairly late-night dose which actually relaxes you and then you drop off to sleep like you habitually do. Actually without it you might be a little anxious otherwise. It's just your body calling out for what it needs to be normal, due to the current level of tolerance you have built up.

Hey wait a minute, wasn't I enjoying this to begin with for it's stimulant effect?

Too late, that effect has left the building.

This is the part that leads studies like this to less-conclusive results.

For me with nothing in the bloodstream almost ever any more (and after all the dust has settled), there's only slightly more energy than being a mainstream addict. I attribute it to the relatively small amount of toxic pressure exerted by the less-than-gram quantities of caffeine I was metabolizing. Yes, I have more energy without it in my system but it's not a miracle and I'm sure many people would not think it's worth it. It's not that toxic, believe me so many things are much worse.

But when I need to go another 12 hours, one cup of coffee will do it.

Never could be a consideration back when I had a tolerance, stronger stimulants wouldn't even help.

Real sleep is the only answer then, you just can't push to the max whenever you really want when you're already strung out.

One of the things that makes the 48-hour study more conclusive about usefulness best practices.

This was their reference 3:

http://scholar.google.com/scholar_lookup?&title=Randomized%2...