- Gold standard: this is a perfect use case for sleep tracking. "Wake me in the sooner of 1 hour or 30 minutes of sleep".
- Upper bound timing. If I can't start a nap within 15-20 minutes, it's probably one I don't need. So a timer set for 35 min would suffice to get me some reasonable duration. This fails if you might need 30+ minutes.
- Caffeine naps. Drink a cup of coffee, start your nap, you'll be up in <40 minutes as the caffeine hits. This doesn't guarantee you'll get a lengthy nap, but it helps ensure you don't wake up groggy.
- Practice. I struggle to nap currently because it's not routine, I usually can't sleep quickly unless I'm exhausted. But I spent a good 6 months getting healthy sleep amounts with a daily nap, and I was usually out within 5 minutes when it was expected.
But in any event: if the coffee has affected you, you're already too late. The idea is to sleep immediately after consuming your caffeine, then wake up as/before it starts to affect you. If caffeine makes you sleepy instead of wakeful, that's probably going to be less pleasant because you won't wake up refreshed.
Finally: I suspect the sleep is helping but feeling useless. Adenosine is one chemical that makes you feel sleepy, and levels are reduced while you sleep. But caffeine is an adenosine blocker, so it's going to stop you feeling that adenosine sleepiness without disposing of it. Good sleep while caffeinated is probably hard to get, but if you succeeded I expect you would lower adenosine levels, but not feel the difference until the caffeine wore off.
Sometimes it can take me 30 minutes just to get to a point, where I might fall asleep! And another 10 to actually fall asleep!
So are these articles actually advocating that someone like me should "nap" for a total of 70 minutes? (40 to fall asleep mid-day, 30 actually sleeping)
The most dangerous thing related to sleep hygiene is creating unpleasant associations with sleep and your bed. If you're lying in bed for long periods getting pissed off, anxious, etc... Your brain will remember these emotions next time you're trying to get some rest and they will keep you from sleeping.
It sounds like hippy shit but it's super important to think of your bed like a fluffy cloud of dreams and wonders. Don't do anything in your bed except sleep & fuck or you will start associations that won't help.
It takes practice, routine and the actual need for a nap, to fall asleep immediately, though.
Also, you can learn to fall asleep faster with practice.