Those in the study were low-income adults in Chennai, India who sleep only 5.5 hours per night on average despite spending 8 hours in bed. The key takeaway was: > increased nighttime sleep had no detectable effects on cognition, productivity, decision-making, or well-being, and led to small decreases in labor supply. I find the result surprising. When I get under 6 hours I see a clear drop off in performance.
If you consider taking 30 minutes of a 6 hour shift to nap, that means they have to be 10% more productive for the 5.5 hours after the nap. I'd suspect hawthorne here, even though it didn't show up in the night treatment group, but it would be interesting to see if this productivity increase is sustained in the long run.
>In contrast, short afternoon naps at the workplace improved an overall index of outcomes by 0.12 standard deviations, with significant increases in productivity, psychological well-being, and cognition, but a decrease in work time.
Time spent napping >> time in bed. They're sufficiently exhausted by mid-day to get higher quality rest than they would by spending the same time in bed.
If you're tired, you're better off getting up at your normal wake time, then taking a nap later.