Thank you so much for all your thoughtful replies. It seems this is quite common. I have to say, that what I am experiencing IS different to the 'dropping off the kerb' jolt. I've had that previously, and that's more of a one off thing before sleep. My scary thing happens sometimes 3 or 4 times a night, and is accompanied by what Helena1 described perfectly as the stomach flip/driving over a hump backed bridge thing, only it feels like it's my heart that is 'flipping'. Sadly, there is no handsome man in the vicinity of my bedroom! I'll get it checked out, though I fear some busy doctor will simply tell me about 'sleep hygiene', and suggest all the usual, warm baths, cool rooms, winding down, and milky drinks. Don't they think we are clever enough to have tried all that!