If you have a healthy immune system, stay active, and don't shove junk food and alcohol in your body all the time, it's easy to have high stamina and only sleep a few hours a night. Also, most guys nowadays have to help out around the house raising kids or doing chores, which takes away from doing that extra stuff. I guess it's kind of a good thing because it's not good for fathers to be at work all the time and totally neglecting the family?