Why do I have uncontrolled shivering, body shaking, teeth chattering even when under an electric blanket, and most often when sleeping, which has awakened me. This is absolutely not a new manifestation, but one I ve had for at least 35-40 years. My ability to consciously control/stop it meets with partial success; the more intense the shivering is, the more difficult it is to voluntarily terminate it. I am a rather healthy 85 year old male living in our home. Thank you Dickii