Effect of Ascent Protocol on Acute Mountain Sickness and Success at Muztagh Ata, 7546 m

Abstract

Investigations studying the secretion of EPO (erythropoietin) in response to acute hypoxia have produced mixed results. Further, the errors associated with the various methods used to determine EPO are not well documented. The purpose of the current study was to determine the EPO response of 17 trained male subjects to either an acute bout of normobaric hypoxia (Hy; n = 10) or normoxia (Con; n = 7). A secondary aim was to determine the error associated with the measurement of EPO. After baseline tests, the treatment group (Hy) underwent a single bout of hypoxic exposure (F(I(O(2))) approximately 0.148; 3100 m) consisting of a 90-min rest period followed by a 30-min exercise phase (50% V(O)(2max)). Venous blood samples were drawn pre (0 min) and post (120 min) each test to assess changes in plasma EPO (DeltaEPO). The control (Con) group was subjected to the same general experimental design, but placed in a normoxic environment (F(I(O(2))) approximately 0.2093). The Hy group demonstrated a mean increase in EPO [19.3 (4.4) vs. 24.1 (5.1) mU/mL], p < 0.04, post 120 min of normobaric hypoxia. The calculated technical error of measurement for EPO was 2.1 mU/mL (9.8%). It was concluded that an acute bout of hypoxia, has the capacity to elevate plasma EPO. This study also demonstrates that the increase in EPO accumulation was 2 times greater than the calculated measurement of error.

Acute high-altitude sickness

“…The major determinants of AMS are the altitude attained [22], individual susceptibility, rate of ascent and degree of preacclimatisation [13,23,24]. Therefore, prevalence of AMS depends very much on the study setting.…”

“…This recommendation, the specifics of which vary slightly depending on the resource cited [52,101,102], derives largely from observational data [103,104] and has only been examined in a prospective, randomised manner in a single study [24]. Because local terrain and logistical factors often prevent adherence to these specific altitude limits on a day-by-day basis, individuals should instead focus on the ascent rate averaged over the entire trip [105].…”

Time-varying signal analysis to detect high-altitude periodic breathing in climbers ascending to extreme altitude

“…As previously described in detail, 34 healthy mountaineers (median age 46 years, range 26-65 years) climbed from the Muztagh Ata base camp (BC) at 4497 m via three high camps (C1, C2, C3) to the summit at 7546 m, within 19-20 days (Fig. 1) [3]. Physiologic recordings were continuously obtained during climbs in the field by a portable device of the size of a palmtop computer (LifeShirt, VivoMetrics, CA, USA).…”

“…The study was performed as part of a medical research expedition to Mount Muztagh Ata (7546 m, China) [3,4,22]. The protocol was approved by the ethics committee of the Zurich University, subjects gave written informed consent, and the study is registered at ClinicalTrials.…”

“…We analyzed data recorded in mountaineers participating in a medical research expedition to Mount Muztagh Ata, 7546 m, China [3,4,23]. Ventilation was continuously recorded through unobtrusive chest wall recordings using portable inductive plethysmography while mountaineers climbed from very high to extreme altitude [13] (from 4497 m up to 7546 m, Fig.…”