This isn't a very surprising result: there's a whole body of research showing sleep deprivation reduces cognitive abilities.
So why do programmers still sleep less than they need to?
Often it's because they're working long hours, and to get time for the rest of their life they cut back on sleep.
I think caffeine and other uppers play a large role as well. I am sitting at a desk doing nothing but I need my brain to be in the state its in when I am doing harrowing physical activity.
I think this warrants a closer look. We do work in a profession that has a cognitive load that is wildly disproportionate to our physiological load. I suspect that some of us need heavy physical activity during the day in order to sleep well.
Anecdotally, when I worked construction I had zero issues going to bed at 9pm and getting to work at 7 every day. But now that I sit at a desk for 9-12 hours a day, I'm rarely able to fall asleep by midnight and getting to work reliably by 8AM is impossible. Ironically, I have no issues sleeping "early" on the weekends when I spend the days out-and-about and doing house work.
> I suspect that some of us need heavy physical activity during the day in order to sleep well.
Yes, this is absolutely the case. I do software as a dayjob, but do an hour or two of heavy physical activity every day (or more on weekends), and sleep great nearly all the time.
When I've had injuries that prevent me from my regular exercise routine, my quality of sleep takes a huge hit. To the point that last time I had a severe ankle sprain, I'd go to a gym (which I don't normally do) just to use one of those arm bike machines to tire myself out.
So why do programmers still sleep less than they need to? Often it's because they're working long hours, and to get time for the rest of their life they cut back on sleep.
If that's you—it doesn't have to be that way. You can set boundaries at work (https://codewithoutrules.com/2019/04/03/setting-boundaries-a...), you can say no to your boss (https://codewithoutrules.com/2018/08/16/how-to-say-no/)... and you'll be doing your employer a favor because your output will go up.