This is an odd one and I am discussing it with the GP, however I wondered if anyone had ever experienced this sensation. On at least 4 occasions now I've woken up to my alarm clock, gone to get out of bed (I keep the alarm clock away from my bed otherwise I hit it and go back to sleep) and as I stand, my legs just give way and I end up sat on the floor. They feel a little shaky and a little numb as if they are still asleep. The sensation is that feeling you get just before you get the pins and needles, but the pins and needles never come in this instance. I have to haul myself up onto the bed or sit where I am for 5 to 10 mins until I my legs feel awake. I don't feel dizzy or faint or anything it is purely my legs can't hold my weight. The GP isn't sure what could be the cause but is investigating another issue I'm having and will come back to this one. She didn't feel that it was something that needed urgent attention and I feel the same. I've had a trawl of the internet (not always a good idea I realise) but not found anything really that could be investigated further. But on the plus side I've not found anything to raise my concern.