Believe it or not even in a FULL body harness you can hang for about 15 minutes before your internal organs start to break down. This is due to the inability to get blood flow to your extremities. Most commonly your legs. And soon after the 15 minute mark your bodys interal organs will begin to break down. You dont have long to hang before things can become very serious after that 15 minute mark. Always bring a knife so you can cut yourself loose and land on your feet.