leg numbness after sleep

My 50-year-old son Who has been diagnosed with sleep apnea and sleeps with a CPAP
wakes up every night after two or three hours of sleep with numbness in the legs
the numbness wakes him up
this has been going on for about 5 yrs
any insight will be greatly appreciated

One thing to look into is paresthesia - https://en.wikipedia.org/wiki/Paresthesia and https://www.mayoclinic.org/search/searc ... aresthesia

You don't mention pain, so I am assuming his leg is not cramping.

After five years he should see a Doc.

If he hasn't died or lost the leg in five years, I see no reason to see a doctor.

He should see a neurologist trained in back problems.

Julie wrote:He should see a neurologist trained in back problems.

I guess he could have something pressing on a nerve only when he lies down.

I would be very surprised if it is a direct result of PAP therapy. Could it be that he doesn't move in his sleep for the first few hours (it would be unusual) for some reason? Crappy mattress, etc)

My experience involved pain rather than numbness, so it may not help, but I mention it just in case. After I began using CPAP I started waking up in the morning with frequent pain a leg, usually at the hip. It could be intense but always faded quickly after I started moving. In the end, I decided that it was probably due to extended pressure concentrated at one point because I was no longer waking up and moving nearly so much during the night. My problem went away when I got rid of my old innerspring mattress and got a memory foam mattress. The Tempur-Pedic used to be a costly luxury item, but there are now much cheaper mattresses on the same principle, with layers of different densities and types of foam. Many of them, like the Casper and the Leesa, are sold over the internet with a long trial period and unconditional right to return the item during that time. Mattresses are subjective, of course, but that completely resolved my problem with pressure points. It is probably relevant that could charitably be described, like Cartman, as big boned.

It could very well be a back issue, a herniated disc or something else where the nerves in the back--probably lower part--are getting pinched in certain positions. I've had something similar happen in the past, but not to the degree you mention and only to one leg. I also get it in one of my arms at times. Mine have been diagnosed as related to a lumbar disc herniation and multiple issues in my neck.