[jeffwass]

This!

I found in university, strangely through sheer accident, (during the first two years of my PhD program in physics) that I performed best on my final exams and written qualifiers with three hours of sleep.

I would sleep 3 hours after late-night study, drink a lot of coffee, and then be able to hyper-focus like a felon on a three-hour-long exam.

[andai]

How was the recovery?

[jeffwass]

Not ideal, but in some cases manageable for several days.

Eg, I remember doing 3 qualifiers on Mon, Wed, and Fri in one week, so a small nap and then back to studying for the next one.

Not a fun week, that.