It is vitally important to keep warm during a fast.
In my own and others experience, a faster can feel cold, especially if they are not burning any calories. The extremities are the most vulnerable in chilling......I used to wear bed socks all day!!!
Stop laughing......thank you.
The chilling can be enervating, inhibits cleansing, and uses up energy reserves at a faster rate than would otherwise be the case.
Use warmer clothing, and if necessary a hot water bottle on retiring to bed.
Even post-fast, the body is still cleansing and skin eruptions are not uncommon after the fast is broken.
But.........please.......keep WARM.