You're so sleep starved you program like a turkey and have to try and do mundane, low risk things for much of the day. Simpler fixes, documentation, clean up technical debt in test cases etc etc. Limit tricky things for the morning after you've warmed up and keep that burst short. But this is of course from birth until n months.

I'm guessing the lifestyle changes are going to have an effect that is large and the effects discussed here, while they may indeed be statistically signficant (who knows?), are going to have an effect so incredibly small by comparison that they really aren't worth considering. But that's pure prejudice on my part - we'll see if there's any data capable of rejecting that hypothesis.

The changes to your sleep are huge. Now if you've had twins... Yeah.