If a person is exposed to low temperatures for a long period of time his core temperature drops. The first symptoms are shivering and mental confusion, followed by a fall in heart rate, respiratory rate, and blood pressure.
While cold can induce difficulty in speaking, lack of muscle coordination and even amnesia, the entire cellular metabolic processes can shut down if the temperature is not recovered. However, things get critical when the body temperature falls below 30 °C. That is when the skin becomes blue and puffy, muscle coordination stops, making walking almost impossible. As pulse rates come down, major organ failure and clinical death can occur.
Yes, Mr Gupta, people do die of cold.
Just for the record, hypothermia deaths are reported from Siberia too. In fact, the famous Dyatlov Pass incident, in which nine ski hikers went missing in the northern Ural mountains in 1959, has been attributed to hypothermia.
This is in response to UP principal secretary (home) A K Gupta's comment that nobody dies of cold.