Color Vision in the Mountains.

This Lessons from History article uses science, aviation, medicine, and mountaineering sources to describe some of the effects of hypoxia, illumination, and other environmental conditions on the eye, the central nervous system, and light and color perception. The historical perspective is augmented by an analysis of an informal observation of the altered perception of red color on a deck of playing cards while climbing Mera Peak in the Himalaya. The appearance of a grayer red color on the cards was initially attributed to the effects of hypoxia alone. Instead, analysis of cards in combination with the low incidence of protan color vision defects at altitude indicated that glare and contrast effects in the extremely bright lighting environment combined with hypoxia likely caused the perception of a grayer red. The incident provides an educational opportunity for review, analysis, and commentary about some of the complex elements that impact color vision.

The Wind-Chill Index.

This Lessons from History article about the wind-chill index (WCI) explores the historical polar and meteorologic literature relevant to the topic and presents unpublished work from 1939. Geographer Paul Siple (1908-1968) was a 6-time Antarctic explorer and scientist who invented and named the WCI in his doctoral dissertation at Clark University. Siple and Charles Passel (1915-2002) performed studies in Antarctica in 1940 that led to publication in 1945. This paper is often credited as the beginning of the WCI. Through years of critiques and revisions by others, these efforts evolved into the wind-chill equivalent temperatures (WCTs) used today. This essay explores the history, the science, and the overlooked originality, simplicity, and details of Siple's unpublished work. The remarkable similarity of the original chart to a current chart is shown by adapting and overlaying the 1939 WCI onto a current WCT chart with its times-to-frostbite data. The writings of Siple, Passel, and others provide an evocative supporting narrative to illustrate some of the problems of living in cold environmental conditions.

The Death Zone: Lessons from History.

This Lessons from History article about the naming of the extreme altitude "Death Zone" explores the historical mountaineering and medical literature relevant to the topic. Swiss alpinist and radiologist Edouard Wyss-Dunant (1897-1983) authored several reports and books about expeditions to arctic regions, deserts, and the Himalaya. Encouraged by the success of a Swiss expedition to the Garhwal Himalaya in 1947, Wyss-Dunant joined his fellow climbers from Geneva on a 1949 expedition to several peaks in the Kanchenjunga region. Wyss-Dunant was then invited to lead the spring 1952 Swiss Everest expedition. Despite this being the first Swiss attempt on Everest and on an untried route, Raymond Lambert and Tenzing Norgay nearly summitted Everest from the Nepal side. Wyss-Dunant earned mountaineering immortality by coining the phrase the Death Zone during the expedition's foray into the upper regions of Everest. Wyss-Dunant went on to become a president of the Swiss Alpine Club and the International Climbing and Mountaineering Federation. His writings and that of others provide an evocative supporting narrative to illustrate some of the problems of living (or dying) at extreme altitude.

High Altitude Deterioration: A Historical Essay.

This wilderness essay about high altitude deterioration will explore the historical mountaineering and medical literature with a limited discussion of physiology. The writings of mountaineers and physician-mountaineers provide an evocative supporting narrative to illustrate one of the problems of living at altitude.

Dull Brains and Frozen Feet: A Historical Essay on Cold.

This essay will review historical and medical aspects of cold exposure, hypothermia, and frostbite during the Napoleonic era. The 19th century writings of Dominique Jean Larrey, Pierre Jean Moricheau-Beaupré, and others are used to provide an evocative supporting narrative to illustrate some of the cold illnesses, physiology, and theory of both an earlier era and the present time. Medical care for over a century followed the how but not the why of treating frostbite and hypothermia slowly with snow or cold water rather than heat. There were 2 main reasons: First was a practical attempt to limit gangrene. Less known, and long forgotten, is a major rationale based on the erroneous theory of heat called "the caloric." Because of these 2 reasons, the slow method of "cold warming" remained standard medical practice well into the 20th century. Although these recommendations are now known to be flawed, some of the reasons behind them will be discussed, along with early but correct observations on afterdrop and circumrescue collapse. There is a long backstory of treatment from 1812 to the present.

Dull Brains, Mountaineers, and Mosso: Hypoxic Words from on High.

Dull and hypoxic brains have been a frequent subject in the medical and mountaineering literature. Deterioration of cognitive and other neurological function occurs at high altitude, with or without high altitude cerebral edema. This historical essay explores a 2014 first-ever English translation of cerebral blood flow studies by nineteenth century physiologist Angelo Mosso. Some of the medical history and physiology of brain function is discussed, but much of the style focuses on quotations from the writings of mountaineers and mountaineering physicians to provide color commentary about dull brains at high altitude.

Dilated hearts at high altitude: words from on high.

From the time of the turn of the twentieth century, dilated hearts and presumed cardiac fatigue in expeditionary climbers and scientists have been the subject of much commentary in the medical and mountaineering literature. Although largely attributed by most, but not all, to left heart strain, the description of dilated hearts in these accounts is clearly that of right heart dilation as a consequence of high and sustained hypoxic pulmonary vasoconstriction with hypertensive remodeling. This essay will feature quotations from the writings of high altitude pioneers about dilated, strained, or enlarged hearts. It will give some brief physiology of the right side of the heart as background, but will focus on the words of mountaineers and mountaineering physicians as color commentary.

Extreme altitude: words from on high.

Medical science has its own objective language for describing the effects of high altitude. Mountaineers' words and metaphors tell the story with subjectivity and feeling. This essay will include only limited physiology about lowlanders and high altitude. Instead, the focus will be literary, using the quotations of 20th-century mountaineers and mountaineer physicians to provide color commentary about the hardship. These are Words From on High.