I'm with R41 -- 40 was the beginning of being middle-aged.. But my 50's have shown me it really is the beginning of the end. I had an sports injury @ 50 that made it difficult for me to exercise, and I put on 20 lbs. The knee surgery I had to try to correct it only left things worse.
According to the National Institute of Neurological Disorders and Stroke (NINDS), the sudden, involuntary jerking of a muscle or group of muscles while drifting off to sleep is called myoclonus. It is caused by sudden muscle contractions, also known as positive myoclonus, or muscle relaxation, which is referred to as negative myoclonus.
1 doctor weighed in: What causes headaches during sleep? 1 doctor weighed in Want a second opinion? Could be a variety of causes- grinding your teeth in your sleep, what you might have eaten or activities during the day, neck posture on your pillow/pillows, Do you get headaches any other time? If this is repetitive, see a Dr. and hopefully determine the triggers. Would you like to video or text chat with me?