What hikermor and teslinhiker write about hypothermia and hyperthermia ring true to me - and you don't want to leave yourself in either scenario with relatively uneducated helpers. In Boy Scouts we use the first few hikes to educate and to assess younger Scouts along the trail - often enough you find a poorly insulated Scout (usually outfitted in sub-par gear by well-meaning parents) who struggles with early hypothermia along a wet hike. Cold wet feet, soaked to the bone, usually they can keep moving and generate enough heat to fend off affects, but they don't enjoy it, or the hike - and inevitably they would break down and begin to lapse into serious trouble if left untreated. And on one hike in Eastern Washington I found myself begin to experience hyperthermia after struggling up a steep arroyo behind more fit Scouts. The best hypothermia kit and treatment is early intervention - stopping, addressing insulation, adding water and food, give the subject some rest, then move along at a slow-moderate pace, and reassess down the trail. If you don't catch it early, break out sleeping bags, shelter, and assign some tasks, such as boiling hot liquid and prepping a bit of food, while more experienced adult leaders and Scouts see to getting their friend out of wet clothes, into dry if possible, and wrapping them up, one sleeping bag inside another, burrito style. Insulation will rapidly warm their core, and the subject should begin to revive. Wrapping a hypothermic victim is easy enough to do, and can be practiced by Scouts at a Troop meeting. When they know what to do, they carry that knowledge with them forever, and can even improvise for self-treatment if out hiking alone.

Hyperthermia is another subject, but just as important. I've had my brain heat up and now look out for symptoms in others on outdoor excursions, and kids in particular aren't quite as witting as to how thin the line can be before the effects of heat exhaustion can occur.