Anas bin Malik (may Allah be pleased with him) narrates that the companions of the Messenger of Allah (ﷺ) would wait for the ‘Isha prayer, and due to overpowering sleep, their heads would droop while sitting, but they would perform the prayer without renewing their ablution.
Hadith Referenceمسند الإمام الشافعي / كتاب الطهارة / 66
Hadith Takhrijأخرجه البخاري: الأذان، باب الإمام تعرض له حاجة بعد الإقامة: (642)، ومسلم: الحيض، باب الدليل على أن نوم الجالس لا ينقض الوضوء: (376).