I have a ventral hernia, is it o.K to do mild set ups? I'm am a 77 year old male, I don't know how are when I got it the hernia, but it does not bother me and gives me no pain. By mild set ups I mean raising my upper body 6 to 8 inches off the floor.

The. The ventral hernia is a split in the abdominal muscles that run up the middle of your stomach. Hernias there are pretty common. They don't have to be fixed unless they are painful but they do look odd when you do a sit-up. The problem is they are certainly made worse by increasing the pressure inside the abdomen like when you do a sit up or strain down like you are passing a bowel movement. But a reasonable approach is if it doesn't hurt and it isn't getting bigger then you could probably do sit-ups. Just like all exercises, don't overdo it!
Ventral. Ventral hernias that are asymptomatic and unchanged are unaffected by sit ups or excercises as long as you do not use weights or strain excessively.