For "people" in general that seems correct in aggregate. For older people we have: http://en.wikipedia.org/wiki/Thirst#Elderly http://en.wikipedia.org/wiki/Th

For "people" in general that seems correct in aggregate. For older people we have: http://en.wikipedia.org/wiki/Thirst#Elderly http://en.wikipedia.org/wiki/Thirst#Elderly You pretty much have to tell old people to drink, after they're too old to know they need to drink. Its also "semi well known" that cold weather tends to mask thirst symptoms, and the resulting dehydration doesn't help much WRT hypothermia prevention, so this claim is, again, not people in general, but the subset of people in an environment colder than they're used to.