It is reported that ʿAbdullāh b. Al-ʿAmr b. Al-ʿĀṣ – Allāh be pleased with them – said:
There are three types of sleep: the incompetent’s sleep, proper sleep, and stupid sleep. As for the incompetent’s sleep, it is to sleep in the morning after sunrise (ḍuḥā time), when people are going about their needs (work), he is sleeping. As for the proper sleep, it is the midday nap (qaylūlah). And as for the stupid sleep, it is to sleep when it is time to pray.
Al-Bayhaqī, Shuʿab Al-Īmān #4409.