Taking naps boosts memory and creativity
theglobeandmail.com
theglobeandmail.com
I usually wake up alert and refreshed and try to make up for the lost time. As an aside, I once forgot to set my alarm and ended up sleeping for about 3 hours. My colleague thought I had left for the day :)
http://lifehacker.com/software/sleep/take-a-caffeine-nap-154...
Mine are a lot longer than 15 minutes, though -- usually 1.5 to 2 hours.
20 minutes is usually that period where you get max rest before entering deeper sleep. The average full sleep cycle is about 90 minutes, so at that point you're usually in light sleep mode again.
My personal experience with coffee is that it ruins my appetite and sometimes gives a caffeine hangover (though it's minor). When I take it with a nap this doesn't happen.
Also, I almost always try to take a nap with a problem or idea in my head. I usually wake up with new thoughts on it.
Also, if people usually drink their stimulant sweet, that's another confounding variable.
(I'm assuming that's what you meant.)
Which is why I said espresso shot, which you can throw in without much time for "ooh I am drinking coffee" thoughts.
Your brain, with its countless centuries of evolution, quickly catches on to these shenanigans. After a few days of caffeine use, it will adapt by growing more adenosine receptors -- either you continue plugging those, too, or you face the avalanche of adenosine when you quit: headaches and unshakable drowiness.
Anecdotally, small amounts of caffeine regularly throughout the day (e.g. thermos of green tea or caffeinated mints) seem less likely to trigger this, but I'm curious how low the threshold actually is.