I have severe Copd and noticed one foot always felt cold and numb. My doctor did a PAD test and everything was good. I’ve also have yearly ultrasound scan on all my arteries and nothing shows up. With that said, I looked for other solutions. I started using a cream with magnesium chloride in it on my feet and ankles at bedtime. I was amazed at how the cold feeling went away. Another big benefit is that I sleep much better and longer than before.