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.
Jerks or âsleep startsâ while falling asleep is a normal occurrence in healthy persons and does not cause difficulties. However, widespread myoclonus includes persistent, shock-like contractions in a muscle group. In some cases, it starts in a particular area of the body and spreads to muscles in other regions. Severe cases cause distortion in movement and significantly limit a personâs ability to eat, talk or walk, says the NINDS. These types of myoclonus indicate an underlying disorder in the nerves or brain.