73 y o good health 4 hours exercise once per week i need 12 hours sleep since several years. if i nap 2 hours i still need 12 hours...

Be seen: I would be seen for a good medical check up and also a sleep study. There are endocrine problems that can cause a person to need a lot of sleep such as in hypothyroidism, and there are also sleep disturbances that can cause it as well such as sleep apnea. If everything checks out, you might have to force yourself to sleep kess by using a strict schedule or you might choose to just sleep on!