Naps: they boost alertness, but “habitual napper” might be a warning sign, not a habit to copy
As I dug into the research, it turned out that naps aren’t just good or bad for you—it depends on when and how long you take them. For example, in a 2021 meta-analysis, taking a short daytime nap had an overall modest effect on cognition, with an effect size of 0.18. That effect was stronger still for alertness specifically, with an effect size of 0.29—but only if those naps were early in the afternoon before 1 p.m., according to researchers.
Nap lengths weren’t as important, but there was some conflicting data related to the “sleep inertia” stage of wakefulness that occurs shortly after waking from a nap. One lab study showed no sign of sleep inertia within 15 minutes—even after naps lasting up to 60 minutes. Late naps, however, do tend to mess with your nighttime slumber, experts told me.
On the other end of the spectrum is the longer term impact. There’s been some research showing that habitual daytime napping (a 2024 meta-analysis of 44 studies showed higher risks for cardiovascular/metabolic disease and all cause mortality). However these are all observational, and it could well be that if you’re napping everyday then you might also have poor sleep / underlying health issues to begin with anyway.
I don’t see this as a reason not to take an occasional power nap during the afternoon – I know from experience it can help! But if you feel like you need a nap most days, it might be worth looking into why 🤔
Nap? When? 😴