Instructor statements show that they were comfortable ignoring the initial signs and symptoms of both dehydration and heat exhaustion because they had "seen it before". Of the three slower students, one was offered water in private from the instructor's emergency reserve: "He (student) said that the instructor offered it in a way that would make him feel like he was a failure if he chose to take it saying: 'listen, if you feel like you can't make it with the group, I have emergency water'. Even though the student chose not to accept the water, he reported that just knowing it was available gave him a sense of security." The student goes on to say: "...I was not in the mood to accept the water (as thirsty as I was), after being told that the water was downhill only a couple of minutes away (primarily for machiso reasons)."
Background Medical Information
Typically heat related illnesses, and associated death, occurs on the second day of exposure especially with non-acclimatized people. As a person becomes acclimatized to a new heat challenge the "thermostat" in their brain resets and they begin to sweat at a lower core temperature and increase the amount of sweat produced. Ultimately a fully acclimatized person may require up to three times more water than when they were non-acclimatized. At the same time their cooling is becoming more efficient, they reduce their electrolyte loss via sweat and urine; electrolyte loss via urine and sweat can be 30-50 time greater in a non-acclimatized person. These initial adaptive processes are about 80% complete within 3-5 days in a healthy individual. Over the next few weeks, as the adaptive process continues, their metabolic efficiency increases and they produce less heat as a cellular by-product enabling them to now engage in activities that, due to increased internal heat production, would have lead to heat stroke while they were non-acclimatized. Also during this time, coronary stoke volume increases - the ventricles relax and stretch allowing more blood to enter - resulting in a lower pulse and less work for their heart. While acclimatized people can "survive" longer in a heat challenge than those who are non-acclimatized, acclimatization requires time and some individuals adapt faster and better than others while some never fully adapt.
Sunburn significantly increases the chance of heat related illnesses because UV radiation destroys skin cells causing inflammation. The subsequent inflammation traps fluids in the tissue spaces and causes/increases dehydration. It is not clear from the information provided in the various reports if John suffered from sunburn. If so, it would have exacerbated his dehydration and further predisposed him to heat exhaustion and stroke.
Heat stroke occurs when a person's core temperature climbs above 105º F. Brain cells die and multiple organs fail at 108º F as body proteins breakdown; death is rapid and irreversible; CPR will not help. Classic heat stroke occurs when dehydration leads to heat exhaustion, and left untreated, to heat stroke. This can, and often does, occur with lower environmental temperatures than purely exertional heat stroke. Exertional heat stroke, where the patient is reasonably hydrated but exercises heavily in a severe heat challenge, leads quickly and directly to heat stroke. If a person dies in an extreme heat challenge and is NOT severely dehydrated many coroners diagnose heat stroke as the cause of death. If dehydration and electrolyte imbalances are present the cause of death is often attributed to them rather than heat stroke. Acclimatization, body metabolism, insulation (clothing, fat, muscle), exercise, etc. play into the equation. Young, fit, healthy people can feel poorly for a long while and then "suddenly" drop.
Click here for a discussion on possible administrative errors, field errors, and solutions.
Are you an outdoor leader, staff trainer, or program administrator? If so, consider taking one of our outdoor program risk management courses.