Erythropoietin acute reaction and haematological adaptations to short, intermittent hypobaric hypoxia.
This study aimed to determine whether brief hypoxic stimuli in a hypobaric chamber are able to elicit erythropoietin (EPO) secretion, and to effectively stimulate erythropoiesis in the short term. In two different experiments, a set of haematological, biochemical, haemorheological, aerobic performance, and medical tests were performed in two groups of healthy subjects. In the first experiment, the mean plasma concentration of EPO ([EPO]) increased from 8.7 to 13.5 mU.ml-1 (55.2%; P < 0.01) after 90 min of acute exposure at 540 hPa, and continued to rise until a peak was attained 3 h after the termination of hypoxia. In the second experiment, in which subjects were exposed to a simulated altitude of up to 5500 m (504 hPa) for 90 min, three times a week for 3 weeks, all haematological indicators of red cell mass increased significantly, reaching the highest mean values at the end of the programme or during the subsequent 2 weeks, including packed cell volume (from 42.5 to 45.1%; P < 0.01), red blood cell count (from 4.55 x 10(6) to 4.86 x 10(6).l-1; P < 0.01), reticulocytes (from 0.5 to 1.4%; P < 0.01), and haemoglobin concentration (from 14.3 to 16.2 g.dl-1; P < 0.01), without an increase in blood viscosity. Arterial blood oxygen saturation during hypoxia was improved (from 60% to 78%; P < 0.05). Our most relevant finding is the ability to effectively stimulate erythropoiesis through brief intermittent hypoxic stimuli (90 min), in a short period of time (3 weeks), leading to a lower arterial blood desaturation in hypoxia. The proposed mechanism for these haematological and functional adaptations is the repeated triggering effect of EPO production caused by the intermittent hypoxic stimuli.
Rodríguez
F A
FA
Unitat d'Hipobària INEFC-UB, Institut Nacional d'Educació Fisica de Catalunya, Universitat de Barcelona, Spain. far@infomed.es
Ventura
J L
JL
Casas
M
M
Casas
H
H
Pagés
T
T
Rama
R
R
Ricart
A
A
Palacios
L
L
Viscor
G
G
D000222:Adaptation, Physiological; D000328:Adult; D000531:Altitude; D001274:Atmospheric Pressure; D001790:Blood Physiological Phenomena; D004906:Erythrocyte Count; D004912:Erythrocytes / Q000166:cytology; D004921:Erythropoietin / Q000378:metabolism*; D006400:Hematocrit; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D000860:Hypoxia / Q000097:blood / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D013997:Time Factors
D006454:Hemoglobins; D004921:Erythropoietin; D010100:Oxygen