Power Nap Time - My Experiments and Conclusion
The 'Setting' : I typically take a power nap when I'm about to embark on a very important task; something that needs a lot of concentration for longer duration. For example, if I've to start a session of coding - I resort to power nap. If I've to make an important decision or work on a presentation - I take power nap before starting my work.
Experiment I: ~ 60 minutes - 90 minutes
I found out that this one is really helpful. You get a total brain-refresh and you are just as fresh as you are in the morning after a good sleep. It also induces the the 'sense of urgency' because you've already spent 60 - 90 minutes of your time without producing anything. But there's a big problem with the 60 minute nap: you can't always have enough time for it. At times, situations may need immediate attention and you can't afford to invest so much of time in the nap.
Conclusion: Ideal time for power nap if you can afford it. Go for it - you won't be disappointed!
Experiment II: ~20 minutes
I've found myself taking 20 minute naps quite often these days. I'd typically set the timer to 20 minutes and go for a quick nap. It's not that I get into deep sleep right away (working on it already) but because the time period is short; I can take it any any time of day. It does have almost the same effect as the 60 minute nap; but you might just not feel 'the same'. The biggest advantage is that you can afford to have it any time and anywhere.
Not Possible In Office - What Do I Do?
I really think that every office should allow employees to take power naps. Maybe they could design the chairs to allow for power naps. But if you can't do that - just sit upright, close your eyes and start deep breathing for 10 minutes. For the first 2-3 minutes, try to flush out all the thoughts from your head and then try to imagine nature (no people in it, please!). It's bound to have the same effect as power napping!
Happy Power Napping!