Anti aging guide

Hypothermia occurs and prevention



How does ANS failure cause hypothermia and How dangerous is cold weather?

Hypothermia occurs when the body temperature falls below 35 °C (95 °F). The three main causative factors are serious, illness (such as sustaining a stroke and lying on the floor all night unable to move), a cold environment, and ANS malfunction. Not all these factors need to operate and, for example, immersion in cold water after a shipwreck will induce hypothermia in previously fit young people. If we are cold, we reduce heat loss by controlling the blood vessels in the skin and reducing the blood flow through our surface layer, and we increase heat production by shivering. Both these reflex reactions are impaired if the ANS is not working properly and the core: periphery temperature gradient is lost. In people who have become hypothermic, it has also been found that there is often a failure to register minor changes in ambient temperature so that they fail to put on extra clothing, close windows, or light fires.

Hypothermia kills, and prevention is certainly better than cure. The home should be kept warm and it is unnecessary to observe the deeply entrenched British habit of opening bedroom windows at night. Half the body’s heat loss occurs through the scalp, so a woolly nightcap makes a useful and not unduly extravagant Christmas present for an aged relative. Hypothermia does represent a very fundamental failure of homeostasis, reducing us to the same level of helplessness as the cold-blooded animals. Indeed, the rigid limbs and the sluggishness of thought and movement of a hypothermic patient are reminiscent of a lizard in the cold of the morning before the sun has started to warm its tissues and activate its chemical reactions. Hypothermia does not, contrary to the popular press, invariably indicate a callous failure by society to protect its frailer members: nor does it usually involve a great deal of suffering, as victims of hypothermia seldom complain of feeling cold if conscious and never if unconscious. The main principle in the treatment is to rewarm the patient in a gradual and controlled way, but there are many complications and the mortality is high except in mild cases.

In an average (pre-global warming) winter in England and Wales there are about 40 000 deaths in excess of those to be expected during a similar period of time during other seasons, but these are mainly due to strokes and heart attacks related to changes, induced by exposure to cold, in the blood and blood pressure rather than to hypothermia. Curiously enough a similar phenomenon has been noted during heatwaves.

Posted by Carol Hudgens - April 27, 2012 at 3:00 pm