Could sexual activity/intercourse cause a carotid artery dissection in your neck if youre laying on your back?

Exercise increases heart rate and blood pressure and so does sex, but this very rarely has adverse health effects. If arterial dissection (carotid, aortic, etc) already is present or if someone is predisposed (e.g. Marfan syndrome), more dissection in theory might occur from increased BP during sex (regardless of laying on back or front). Discuss with your doctor if you have concerns about it.

Assuming there has been no recent trauma to the head or neck, that you do NOT possess a connective tissue disease, or possess any genetic disorders affecting large arteries in the neck, or aorta, see no statistical reason to fear a carotid artery aneurysm. If there are underlying conditions not mentioned, or a family history of dissection, this would modify the responses.