From nothing. To possible arterial blockages. Check, blood pressure, pulses, have an exam . Some other conditions, diabetes, endocrine issues can cause the feeling without any critical blockages. Severe with cold digits or limbs, to gangrene if not repaired timely. Also depends on part of body-brain stroke heart attack kidney failure.
Cool extremities . Or pain with exertion.
Bad circulation. A cold and blue extremity would be two signs of poor circulation to that extremity. Read more...