1.
The practical aspects of insulin at high altitude.
Richards, P, Hillebrandt, D
High altitude medicine & biology. 2013;(3):197-204
Abstract
With the increasing prevalence of diabetes and current social philosophy of enablement, many more diabetics are travelling to high altitude where the rate of AMS in Type 1 diabetic mountaineers is no different than nondiabetics. Numerous effects of exercise, both degree and duration, dietary change, illness, stress, mountain sickness, counter-regulatory hormones, and altitude increased sympathetic output, and catecholamines have led to conflicting accounts of insulin requirement increasing or decreasing at altitude. Overall, it would appear that the effects of diet and exercise outweigh those of altitude. Good control requires continual insulin dose adjustment with frequent feedback from blood sugar testing, but glucometers can over- or under-read at altitude. Additionally, heat or cold exposure can degrade insulin efficacy; strategies for storing insulin are described.
2.
Acute mountain sickness prophylaxis: a high-altitude perspective.
DeLellis, SM, Anderson, SE, Lynch, JH, Kratz, K
Current sports medicine reports. 2013;(2):110-4
Abstract
Acute mountain sickness (AMS) is the most common form of altitude illness affecting athletes and adventurists who work or play at elevations greater than 10,000 ft above mean sea level. Considerable research has been conducted to mitigate risk for those who work or play in environmental extremes. This article describes the experiences of a group of U.S. Army Special Operations soldiers who tested recommended doses of acetazolamide prophylaxis for AMS during six expeditions to elevations between 19,000 and 23,000 ft. In addition, we briefly review the literature as it pertains to prophylaxis of AMS. In our experience, prophylaxis with the recommended doses of acetazolamide resulted in fewer AMS symptoms and seemed to confer a higher likelihood of successfully summiting each peak. We conclude that acetazolamide is an acceptable choice for AMS prevention along with a slow, controlled ascent and proper fitness, nutrition, clothing, and gear.
3.
Energy at high altitude.
Hill, NE, Stacey, MJ, Woods, DR
Journal of the Royal Army Medical Corps. 2011;(1):43-8
Abstract
For the military doctor, an understanding of the metabolic effects of high altitude (HA) exposure is highly relevant. This review examines the acute metabolic challenge and subsequent changes in nutritional homeostasis that occur when troops deploy rapidly to HA. Key factors that impact on metabolism include the hypoxic-hypobaric environment, physical exercise and diet. Expected metabolic changes include augmentation of basal metabolic rate (BMR), decreased availability of oxygen in peripheral metabolic tissues, reduction in VO2 max, increased glucose dependency and lactate accumulation during exercise. The metabolic demands of exercise at HA are crucial. Equivalent activity requires greater effort and more energy than it does at sea level. Soldiers working at HA show high energy expenditure and this may exceed energy intake significantly. Energy intake at HA is affected adversely by reduced availability, reduced appetite and changes in endocrine parameters. Energy imbalance and loss of body water result in weight loss, which is extremely common at HA. Loss of fat predominates over loss of fat-free mass. This state resembles starvation and the preferential primary fuel source shifts from carbohydrate towards fat, reducing performance efficiency. However, these adverse effects can be mitigated by increasing energy intake in association with a high carbohydrate ration. Commanders must ensure that individuals are motivated, educated, strongly encouraged and empowered to meet their energy needs in order to maximise mission-effectiveness.
4.
Endocrine aspects of high altitude acclimatization and acute mountain sickness.
Woods, DR, Stacey, M, Hill, N, de Alwis, N
Journal of the Royal Army Medical Corps. 2011;(1):33-7
Abstract
The acute acclimatization to high altitude is underpinned by a diuresis (and to a lesser extent a natriuresis) that facilitates a reduction in plasma volume. This allows a haemoconcentration to occur that increases the oxygen carrying capacity of a given volume of blood, a vital effect in the presence of a reduced partial pressure of oxygen. This critical acclimatization process is orchestrated by the endocrine system. This review will present the key evidence regarding the changes in several important hormones that affect this process.
5.
[Optimized nutrition for alpine athletes].
Veitl, V
Wiener medizinische Wochenschrift (1946). 2000;(8-9):191-4
Abstract
Nutritional habits of athletes usually don't differ from those of the remaining population. Psychic as well as physical capability are nutritionally dependent. In order to achieve uttermost capability for athletic activities, an optimisation of the daily nutrition, and of the "nutrition at the mountain" is necessary. The alpine athlete must adapt his diet to the intensity of his physical burden on the one hand and to the changed conditions in the height on the other hand. Nutritional recommendations are discussed.