This morning, I woke up terrified: a weight was pinning down my chest. I was sleeping on my back with my hands across my chest. Prior to that I was having a dream that was neither frightening or unpleasant. I was fully awake and able to think rationally. I tried to call my husband beside me, but couldn't open my mouth. I also couldn't move, but didn't feel there was anything wrong with my body it felt more like a large cat was sitting on my chest. The experience felt like it lasted for a few minutes. Is there any medical explanation for this?

Dr Fred Kavalier answers your health question:

Your question is a beautiful description of sleep paralysis, an uncommon but well-recognised condition. Some people feel the "paralysis" when falling asleep, others when waking up. The feeling that something is sitting on your chest is one of the recognised symptoms. Sleep paralysis is neither serious nor dangerous, but it can be frightening. Occasionally it is linked to narcolepsy, which causes sudden sleepiness during the day. Sleep paralysis is caused by a disturbance of REM (rapid eye movement) sleep. No one knows the cause, but fortunately it doesn't usually happen very often. There are descriptions of the condition on the net, and a self-help website,, set up by a fellow-sufferer.

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