Cold sensitivity or cold intolerance is unusual discomfort felt by some people when in a cool environment.
There is much variation in the sensitivity to cold experienced by different people, with some putting on many layers of clothing while others in the same environment feel comfortable in one layer.
Cold sensitivity may be a symptom of hypothyroidism, anemia, fibromyalgia or vasoconstriction (according to article Sauna). There may also be differences in people in the expression of uncoupling proteins, thus affecting their amount of thermogenesis. Mental activity may also play a factor in perceived temperature.