> Because earplugs also tune out the sounds of an alarm clock.

No criticism! I just find it funny in the context of this article. An alarm clock is the last thing one should use if natural and healthy length of sleep is a priority. I know that society creates the pressure, but just to stay in the context of the article...

Myself, I have not used an alarm clock in years and I would rather face huge pay cuts (which is exactly what is happening) or even worse rather than ever go back to forced wake-up, which I would now consider a direct violent attack on my person. Exceptions are fine, but no way I would let that be imposed on me as "normal part of life" ever again.

By the way, the brain, i.e. its zeitgebers are really good at waking you up.

I had to take a chelator (binds to heavy metals in the body and makes them excretable; details are in my recent comment history) regularly (keeping a low steady dose in blood instead of pulse-dosing). It meant waking up every 4 hours at the latest. I soon didn't need an alarm clock even for that any more! My brain would wake me up, and it would even take into account my overall health status. When according to my symptoms I had more metals circling I would wake up after maybe 1.5 or 2 hours, when I felt fine I would wake up after 3.8 hours or so, just before the scheduled 4 hour mark. I did that for years, it was completely automatic. Also, when I went off the chelator for a week I would instantly, starting that same following night, sleep through and not wake up! My brain (the zeitgebers) even took into account if I took the chelators and needed to wake up or not. Amazing thing, that brain.

After years of my not quite voluntary experiments I trust my brain a lot more when it comes to decisions such as the sleep schedule. It's far more fine-tuned and takes into account so much more, it's not a blunt regulation at all but highly sophisticated. In my experience, not just with sleep but there's more such "involuntary experiments" I got into through my heavy metal issue, the brain's regulatory circuits not connected to consciousness nevertheless actually do incorporate a lot of information most people might think are for our conscious self only, we just don't usually realize it (or trust it). My conclusion is that while the conscious part cannot (easily, directly) access information from the areas outside of consciousness, the opposite is not true and the rest of the brain uses all information. It's almost as if my brain always knows what I'm up to, spooky :-)

By the way, in my sleep experience much amplified by the health issues caused by heavy metal poisoning, the first 1-3 hours of sleep and the very last part - the one that many people are missing out on - stand out. When I was at the peak of my (mercury) problems I might be okay all day, but I would wake up between 2 and 3 am knowing with absolute certainty I had cancer, or something really bad. My conscious self knew that was nonsense, at least after a while of observing those patterns, but the feeling was there. Those first 2 or 3 hours also were the ones were my body had the most problems. Everything was fine and nice after that first part of sleep. The last part, hours 6-8 or even just 7-8, stand out because if you wake up just before that you feel fine and fresh, but if you wake up after that part you may actually feel a bit worse. However, and as I said I experienced the effects much amplified because of the specific issues I had at the time, without that last part of sleep something was missing, something.. essential. It was like - and that is not a literal description because I have no idea what my body did! - as if the body had thrown out a ton of "garbage" in that very last phase. So if you missed it you might feel better because that "garbage" wasn't in your blood, but long term it was better to not skip "garbage duty". That's only my "by feel" description!

That feeling is similar to what more people may know as what happens when yo have to sleep during the day, and instead of just superficially napping you actually fall into "real" sleep. When you wake up you may feel groggy for an hour. With my involuntarily gained experience I would now advise to go through with it, if your body does that it has a reason! I always felt worse short term but much better long term with that very last sleep phase.

I went through such phases over almost a decade of recovery, and the more I got better overall, with clinically proven (unexpected) successes, the less my body wanted any of that. I only had the desire to sleep during the day when I really needed it, it got less and less the farther I got overall. So I would not treat the body's desire to sleep at any time lightly, even during daytime. Most of your brain involved in regulating your body is not accessible to consciousness, but it has a lot more data and you should think twice if you really want to use the consciousness' ability to override some things. Instead, isn't it reasonable to hand over control to where the data is, i.e. to let such things like sleep pattern not be regulated by alarm clocks and social pressures but by your "inner self"? This reminds me, when I worked there (contractor) there was a "sleep room" in Oracle building 100 (Redwood Shores)...