I think that the shivers are from being under the blankets all night and then after waking up you get the shivers because of an airy place in the blankets from when you moved around some, thus making you feel cold for a minute or two. I don't personally think it has anything to do with your circulation. I am not a doctor though. I get shivers all during the day and as far as I knowI don't have anything wrong with circulation problems.
If you had sleep apnea you would notice more symptoms than shivering. You would gasp for air in the middle of the night, have tremendous snoring (ask someone who sleeps next to you =o)..
You could try taking your temp in the morning for the next couple days. See what it shows, but again I do not think it has anything to do with your body's circulation or your body not being able to regulate it's temp.
Take care! If in doubt ask your Doctor..
I do know that body temp is low first thing in the morning. It comes up pretty quickly once you start to move around, get the metabolism revved up. When I was trying to get pregnant I had to take my temp every morning before I started moving around. Got the basal temp that way. Not sure why you get shivers. I'm with Steph on that one; I get an occasional shiver during the day or chills down my thighs. Not a health problem as far as I know.
I feel shivers in the elbows,chest and back about 3hrs after going to bed;other parts of body,esp feet become hot.
Only way to get back to sleep is a hot water bottle.
Wonder if this is due to body temp reduction,humidity from the mattress.....? Thyroid has been checked & found to be OK
Doctor says there are no answers but maybe someone has!