Divaswapna — daytime sleep — is one of the things classical Ayurveda is most consistently against. It is named as a cause of Kapha increase, of blocked channels, of heaviness, dullness, congestion and a specific loss of digestive strength. The texts list it alongside suppressed natural urges as a habit that quietly builds disease.
And then they make one exception, and only one: summer.
The reasoning is worth following because it shows the model working. In Grishma the nights are at their shortest and the days at their longest and hottest. The heat is dehydrating and Vata-provoking. Bodily strength is at its annual floor. Under those specific conditions the texts hold that a daytime rest replaces what the short night failed to give and offsets the Vata that the dryness is accumulating — and that the usual Kapha penalty does not apply, because Kapha is naturally pacified by the heat anyway.
Every clause in that reasoning is seasonal. Change the season and the exception evaporates. Which is why the classical position is not "naps are fine" but "a nap is medicine in Grishma and a mistake in Shishira" — a distinction that a general rule could never carry.
The practical version: a short rest in the hottest part of the afternoon, in a cool shaded room, ideally not immediately after a large meal. Not three hours. Not on the sofa in front of a screen. And when the rains arrive in a few weeks, it stops.
A useful exception to the exception: if you are strongly Kapha, or currently congested, or overweight, the texts still advise against it.