Physiological profile of world-class high altitude climbers

The functional characteristics of six world-class high-altitude mountaineers were assessed 2-12 mo after the last high-altitude climb. Each climber on one or more several occasions had reached altitudes of 8,500 m or above without supplementary O2. Static and dynamic lung volumes and right and left echocardiographic measurements were found to be within normal limits of sedentary controls (SC). Muscle fiber distribution was 70% type I, 22% type IIa, and 7% type IIb. Mean muscle fiber cross-sectional area was significantly smaller than that of SC (-15%) and of long-distance runners (LDR, -51%). The number of capillaries per unit cross-sectional area was significantly greater than that of SC (+40%). Total mitochondrial volume was not significantly different from that of SC, but its subsarcolemmal component was equal to that of LDR. Average maximal O2 consumption was 60 \ub1 6 ml\ub7kg-1\ub7min-1, which is between the values of SC and LDR. Average maximal anerobic power was 28 \ub1 2.5 W\ub7kg-1, which is equal to that of SC and 40% lower than that of competitive high jumpers. All subjects were characterized by resting hyperventilation both in normoxia and in moderate (inspired O2 partial pressure = 77 Torr) hypoxia resulting in higher oxyhemoglobin saturation levels in hypoxia. The ventilatory response to four tidal volumes of pure O2 was similar to that of SC. It is concluded that elite high-alitude climbers do not have physiological adaptations to high altitude that justify their unique performance

Effects of dietary nitrate supplementation on microvascular physiology at 4559 m altitude – a randomised controlled trial (Xtreme Alps)

Native highlanders (e.g. Sherpa) demonstrate remarkable hypoxic tolerance, possibly secondary to higher levels of circulating nitric oxide (NO) and increased microcirculatory blood flow. As part of the Xtreme Alps study (a randomised placebo-controlled trial of dietary nitrate supplementation under field conditions of hypobaric hypoxia), we investigated whether dietary supplementation with nitrate could improve NO availability and microvascular blood flow in lowlanders. Plasma measurements of nitrate, nitrite and nitroso species were performed together with measurements of sublingual (sidestream dark-field camera) and forearm blood flow (venous occlusion plethysmography) in 28 healthy adult volunteers resident at 4559 m for 1 week; half receiving a beetroot-based high-nitrate supplement and half receiving an identically-tasting low nitrate 'placebo'. Dietary supplementation increased plasma nitrate concentrations 4-fold compared to the placebo group, both at sea level (SL; 19.2 vs 76.9 μM) and at day 5 (D5) of high altitude (22.9 vs 84.3 μM,

Aspirin gegen das Altern? : für wen und wieviel?

Aspirin has been successfully used in the secondary prophylaxis of myocardial infarction, cerebral vascular events and peripheral arterial disease. Regular aspirin intake may further be beneficial in asymptomatic healthy male with cardiovascular risk factors over the age of 50. There is no good evidence that aspirin prevents the development of atherosclerosis and thromboembolic events in healthy individuals

Ciprofloxacin-induced hematuria

We used ciprofloxacin, a quinolone-derivative, to treat a lung infection due to Pseudomonas aeruginosa in an adult cystic fibrosis patient. On three different occasions the use of ciprofloxacin was associated with the development of an asymptomatic hematuria with red blood cell casts. The mechanism responsible for this hematuria is presently unknown, but clinicians should be aware of this potential adverse effect of ciprofloxacin

Successful treatment of acute mountain sickness with dexamethasone.

A double blind, randomised, placebo controlled trial of treatment with dexamethasone for acute mountain sickness was performed in the Capanna "Regina Margherita" at an altitude of 4559 m in the Alps Valais. After 12-16 hours of treatment (8 mg dexamethasone initially, followed by 4 mg every six hours) the mean acute mountain sickness score decreased significantly from 5.4 to 1.3, and eight of 17 patients became totally asymptomatic. Mean arterial oxygen saturation rose from 75.5% to 82.0%, and there was a small increase in standard spirometric measurements. In the placebo group none of these variables changed significantly. It is concluded that dexamethasone may be used as emergency treatment for acute mountain sickness to facilitate safe descent to a lower altitude