Partly, this discussion has strayed into hostile territory because we all have a tendency to confuse good advice with hard scientific evidence. Good advice may not always be "good" to the extent it claims - and science can inform us about its quantitative value. For instance, chicken soup may not cure the common cold, but science does confirm that it may be useful - for a number of somewhat complex and unrelated reasons. Those who used chicken soup as the sole treatment regimen for the cold were ill-informed - but anyone who might contend that it is of no value is almost equally wrong. And here's my point - the rate of mortality and morbidity from eating chicken soup is quite low, yet its salutary effect on the sick is well-documented in experience, thus, it is recommended! To the case in point I offer the following:

In support of keeping head and neck warm -- Three medical sources after a cursory review of the hypothermia treatment literature on the Internet:

?Individuals employing heated, humidified aerosols have been impressed with their benefits, which appear greater than can be explained by the small heat exchange. Most of the heat transfer takes place in the upper airway, not in the lungs where it would warm the heart. Investigators have speculated that warming the base of the brain and the brain stem may be responsible for the salutary effects.?

?The hypothalamus, a portion of the brain stem, is the body?s main thermometer
where most of the information from the temperature receptors in the core and skin are
integrated. The hypothalamus monitors these temperatures and when they start to vary, it
signals the body to bring the temperature back by voluntary and involuntary means.?

?Airway Warming
Airway warming accelerated rewarming to a statistically significant degree, compared with passive rewarming, whether it occurred before and/or after the period of airway warming. There is a thermal countercurrent heat exchanger in the cerebrovascular bed of humans known as the rete mirabile. This heat exchanger may preferentially rewarm the brainstem.?

So, until something better comes along, I will continue to insist on head and neck coverings (along with a whole host of recommended actions in cold weather) as beneficial to the person operating in cold conditions or suffering from early signs of hypothermia.

Cheers,