Survival skills
A human being can survive an average of three to five days without the intake of water. The issues presented by the need for water dictate that unnecessary water loss by perspiration be avoided in survival situations. The need for water increases with exercise.
Prahlad Jani
After fifteen days of observation during which he reportedly did not eat, drink or go to the toilet, all medical tests on Jani were reported as normal and researchers described him as being in better health than someone half his age. The doctors reported that although the amount of liquid in Jani's bladder fluctuated and that Jani appeared "able to generate urine in his bladder", he did not pass urine. Based on Jani's reported levels of leptin and ghrelin, two appetite-related hormones, DRDO researchers posited that Jani may be demonstrating an extreme form of adaptation to starvation and water restriction. DIPAS stated in 2010 that further studies were planned, including investigations into how metabolic waste material is eliminated from Jani's body, from where he gets his energy for sustenance, and how he maintains his hydration status.