I Have Difficulty Sleeping At Night Because Of The Sudden

I have difficulty sleeping at night because of the sudden onset of cold feet which awakens me. Often there is a palpable wave do coldness that sweeps over rhe lower part of my leg from just above the ankle to the rest of my foot. I have been solving the problem by getting out of bed and walking around the house for 15-20 minutes. The seems to alleviate the coldness. This will happen 3 or 4 times a night. I seldom have the "coldness sensation" during the day