Body state after enlightenment I've heard (not from Buddhist texts) that after enlightenment the investment in the body dwindles becomes delicate and less resistant to disease ,and that the body needs to be prepared first.So what Buddha had went through before Nirvana was important.Or what the yogis do in kryia yoga .
Examples of Ranamnakrishna and Maharishi Raman dying of cancer .
There is even claim that some might die right after nirvana.
Another claim is that there is no longer unconscious sleep,One is always awake /sleeps less .
Example of krishnamurti not sleeping well and having migraines.
If there is any such thing what do Buddhist texts say about the state of the body after nirvana ?
The Buddha lived till the age of 80, which is 45 years after his enlightenment, according to tradition.
Based on the Pali Canon, he seemed to have lived a mostly healthy life and only suffered from dysentery a short while before his death.
From the essay &quot;Footprints in the dust: Buddha’s travels in India&quot; by Ven. S. Dhammika:

In the famous Mahaparinibbana Sutta we know that he went from Rajagaha
to Kusinara via Nalanda, Patna and Vesali, a total distance of about
300 kilometres.

I think to travel 300 km on foot, he must have been quite healthy.
Similarly, his disciples like Ven. Sariputta and Ven. Moggallana were arahats and also seemed to have lived generally healthy lives.
As far as I know, enlightenment does not have a detrimental effect on the body. Of course, they are no longer attached to their bodies, so they may not lovingly take care of their body, looks and health in the same way non-enlightened folk would. They would follow the Middle Way in taking care of their health i.e. neither extreme asceticism, nor indulgence and vanity.
Ageing, disease and death affects all sentient beings, regardless of whether they are enlightened or not. All conditioned things are impermanent (sabbe sankhara anicca).