[ 2008-11-27 17:11 ]
Studies have found that the body’s response to cold changes significantly over a lifetime, with older people, especially men older than about 60, less able to maintain their core temperature at a given cold exposure than young people.
But a 2002 Finnish review in The International Journal of Sports Medicine also noted that older people had a reduced skin sensitivity to the cold and a reduced subjective perception of how cold it is, thereby making them slower to react to protect themselves and more vulnerable to death from hypothermia.
The skin’s protective reaction of constricting surface blood vessels is slower with age, and the cold-induced rise in metabolic rate is also weakened in older people, but the mechanism is unknown.
Cold sensitivity at any age is related to general ill health, especially an abnormally low body mass index and other factors like thyroid malfunction, so older people with these problems may feel more uncomfortable in the cold.
In mapping the temperature sensitivity of the body surface over the life span, a 1998 study reported in the journal Somatosensory & Motor Research found that the greatest age-related changes took place in the extremities, especially the feet, where sensitivity thresholds often become too large to measure.
（来源：纽约时报网站 实习生许雅宁 英语点津 Annabel 编辑）