Relationship between excessive erythrocytosis and acute mountain sickness: a field study

Abstract

BackgroundAlterations in hematology, especially erythroid changes, may be involved in acute mountain sickness (AMS) at high altitude. This study aimed to identify the relationship between excessive erythrocytosis and AMS following different durations of high-altitude exposure.MethodsA total of 692 healthy young Chinese men were recruited for the study in June and July of 2012 and were divided into the following five groups: I) the 24-h group (24 hours after arrival at Lhasa, 3,700 m, n = 261); II) the 7-d group (exposed at Lhasa, 3,700 m for seven days, n = 99); III) the re-exposure group (re-exposed at Yang Bajing, 4,400 m for seven days after >1 year of acclimation at 3,700 m,n = 94); IV) the acclimated group (>1 year of acclimation at 3,700 m, Lhasa, n = 42); and V) the sea-level control (control group, Chengdu, n = 196). Case report forms were used to record the subjects’ demographic information and AMS-related symptoms. All of the subjects underwent routine blood tests.ResultsThe red blood cell (RBC) count fell slightly but was not significant upon acute exposure to high altitude, whereas the hemoglobin concentration ([Hb]) increased significantly. After high-altitude re-exposure, both of the [Hb] and RBC count showed significant increases. The incidence of AMS was 65.1%, 26.3% and 51.1%, respectively in the 24-h, 7-d and re-exposure groups. The [Hb] (P = 0.024) and hematocrit (P = 0.017) were greater in the AMS+ individuals than in the AMS- individuals in 7-d group. A correlation analysis revealed that the [Hb] and hematocrit were closely related with AMS score in 7-d and re-exposure groups, while the RBC showed a correlation with AMS score only in the re-exposure group. The AMS incidence was lowest when the [Hb] was between 140 and 160 g/L in the 24-h and 7-d groups.ConclusionsAMS is associated with both [Hb] and excessive erythrocytosis. Additionally, our findings indicate the existence of an optimal [Hb] for preventing AMS.

Sex-based differences in the prevalence of acute mountain sickness: a meta-analysis

“…The second mechanism relates to the concentration of erythropoietin (EPO). After exposure to high altitude, blood components associated with oxygen delivery are affected; the concentration of hemoglobin and count of red blood cells increased sharply [44], which are thought to be advantageous compensations [45]. Testosterone is known to be an androgen that promotes erythropoiesis, which may possibly improve oxygen carrying capacity by increasing EPO levels, conferring an advantage on men at high altitudes [46].…”

Physiological Responses in Humans Acutely Exposed to High Altitude (3480 m): Minute Ventilation and Oxygenation Are Predictive for the Development of Acute Mountain Sickness

“…A large number of studies tried to establish differences in physiological responses between subjects developing acute mountain sickness (AMS) and subjects staying healthy when acutely exposed to high altitude. Various physiological parameters have been suggested as being potentially explanatory for the susceptibility to AMS, that is, ventilatory, cardiovascular, hematological, and metabolic parameters (Roach et al, 1998;Burtscher et al, 2004;Karinen et al, 2010;Richalet et al, 2012;Spliethoff et al, 2013;Ding et al, 2014;Faulhaber et al, 2014;Sutherland et al, 2017). Arterial or peripheral oxygen saturation (SaO 2 , SpO 2 ) has been emphasized as being the most promising predictor variable by several (Roach et al, 1998;Burtscher et al, 2004;Karinen et al, 2010;Richalet et al, 2012;Faulhaber et al, 2014), but not all (Grant et al, 2002;O'Connor et al, 2004) studies.…”

Unusual Cause of Branch Retinal Artery Occlusion: Polycythemia in a Transgender Man From Unregulated Testosterone Use

“…The highest elevation of Cradle Mountain is 1545 m. We raise the possibility of relative hypoxia as his precipitating factor while on the chairlift. Ding et al demonstrated that healthy young subjects had raised Hb and hematocrit after a 7-day exposure to high altitudes at 3,700 m, 15 whereas Zangari et al 16 showed that patients with polycythemia vera living at 5,000 feet (approximately 1500 m) had 3.9-fold increase in the odds of a history of thrombosis. High altitude stay has been shown to cause hypercoagulability not only by increasing Hb and platelet count but also by raising the fibrinogen level, platelet activation factors, and plasminogen activator inhibitor 1 levels.…”