What happens is the fire (agni) starts to concentrate in your middle to be able to digest the dense and heavy foods needed for your Winter coat. And so it detracts from the extremities. And if you're prana is not robust it might turn to Vata and cause the cold hands and feet such as chill blains.
Soak your feet in some good grade magnesium flakes. We see minerals as grounding (from the earth) and so calms the Vata dosha down. Increasing circulation is important for Vata but if they are exhausted then excess exercise will only make it worse as you may not be breathing right. And Prana not handled correctly causes Vata imbalances.
And like we say in Ayurveda, your skin is the largest digestive organ in the body and to get the benefits of magnesium you don't need to bother an impaired digestive system.
You will sleep better, your circulation improved and feel calmer during the day.
I sell great quality Ancient Minerals magnesium flakes in store for $20/bag.