Environmental Hazards, Hot, Cold, Altitude, and Sun

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Extreme environments

Humans have colonized most areas of the planet, including areas where the environmental conditions are extremely harsh. Native populations to these areas have developed strategies that include clothing, shelter, technology, and behavior, as well as physiologic adaptation, over generations. Short-term visitors can adjust to these austere environments provided they have the knowledge and time to acclimatize sufficiently. There has been an increase in both recreational and adventure travel to

Heat-related disorders

Humans are well adapted to hot climates but require a period of acclimatization from cold/temperate climates, especially in humid conditions. There is considerable variability of thermal tolerance between individuals, but ultimately everyone will succumb if the duration and intensity of exposure are sufficiently challenging.

Accidental Hypothermia

Hypothermia occurs when the core temperature decreases to less than 35°C and can be classified as mild (35°–32°C), moderate (32°–28°C), or severe (<28°C).15, 16 The Swiss classification should be used in the field by rescuers.17 Risk factors for hypothermia include extremes of age, homelessness, trauma, poor nutrition, exhaustion, mental illness, and alcohol and drug abuse.

Hypothermia affects almost every organ system. Cerebral metabolism increases initially but then declines by 6% for each 1°C

Summary

Humans can successfully acclimatize to and perform reasonably well in extreme environments, provided that sufficient time is given for acclimatization (where possible) and if they use appropriate behavior. This is aided by a knowledge of the problems likely to be encountered and their prevention, recognition, and treatment.

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