I have no such experience, but I can think of why the limb movements happen. It is, to me, an indication of restlessness and underlying anxiety that keeps you from entering successive stages of sleep. IOW, you are stressed and your system is 'aroused' sufficiently, even while attempting to sleep, that your unconscious mind is just hanging onto sleep with its bared teeth. Also, if your heart is stressed with low blood supply, it feels different in some people and that can be a signal to your sympathetic nervous system to keep you alert, anxious, aroused, wanting to enter into full-blown fight-or-flight response...including strange dreams and thrashing limbs.
That is to say that your body is doing precisely what it thinks it needs to do to save you, even while you're in bed and asleep. Meaning 'perfectly natural and understandable'.