In Jainism, especially during and after performing tapasya (austerities such as fasting), the period known as parna refers to the ritual breaking of the fast. There is no universally fixed rule in Jain scriptures specifying the exact number of minutes a tapasvi (one who has done austerity) should wait before sleeping after parna. However, according to traditional Jain practice and acharya guidance:

• It is generally advised that a tapasvi should not go to sleep immediately after parna.
• Traditionally, tapasvis are encouraged to remain awake and engaged in spiritual activities such as pratikraman, swadhyaya (scriptural study), or samayik for some time after parna to maintain alertness and gratitude.
• Some Jain monks and elders suggest waiting at least 48 minutes (one muhurat) after parna before going to sleep, to aid digestion and to stay spiritually mindful.
• Ultimately, practices may vary by sect (Shwetambar, Digambar, Sthanakvasi) and individual health, but the emphasis is on mindfulness and avoiding immediate sleep post-parna.

It is always best to follow the guidance of your local Jain guru, acharya, or the tradition of your Jain community.