Answer. There are many forums that are impossible or impossible for a normal person to do, are done by special types of means that can go to extremes to do some of these types of meditation There is Inside icy lake meditation. Sadhus for years, in cold years. The other is among the dead.  The sadhu meditates until he dies. This is also called final meditation. In the third high-altitude meditation, the sages meditate on a high altitude place like a cold icy mountain till the end of their life.