If you feel cold all of a sudden, there are usually several factors: First, in the early stage of viral cold, you will feel cold all over your body, and it will be accompanied by cold shivers and chills. Second, sudden chills should also be related to cold and insufficient caloric intake in the body, which can occur when the body’s nutritional status is poor and caloric intake is insufficient. Thirdly, drowning in cold water will also show clinical symptoms and performance of sudden chills. Fourthly, when exposed to cold environment for a long time without paying attention to keep warm, the above clinical symptoms and performance will also occur. Fifthly, if the central nervous system in the body is damaged due to nerve dysfunction, for example, the thermo-sensory center is damaged, a sudden chill may occur.