Nap

[7] Napping enhances alertness in young adults and adolescents during afternoons’ performances, which affect efficiency.

[10][6] In adults, a causal association has been found between habitual daytime napping and larger brain volume.

[17] A 2016 meta-analysis showed that there may be a correlation between habitual napping for more than an hour, and having an increased risk for cardiovascular disease, diabetes, metabolic syndrome or death.

No causal relationship was established: the link may be to do with people taking a longer nap in response to the pre-existence of other risk factors.

[18] Habitual naps are also an indicator of neurological degradation such as dementia in the elderly, as reduction in brain function causes more sleepiness.

[19] For idiopathic hypersomnia, patients typically experience sleep inertia and are unrefreshed after napping.

[23] According to The Sleep Foundation, Psychology Today and Harvard Health Publishing, these are the best practices for napping:[13][24][14]