Effect of a Single Session of Intermittent Hypoxia on Erythropoietin and Oxygen-Carrying Capacity.

Mercedes J Nagel,Caitlin P Jarrard,Sophie Lalande

doi:10.3390/ijerph17197257

Mercedes J Nagel, Caitlin P Jarrard + Show 1 more

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https://doi.org/10.3390/ijerph17197257

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Abstract

Intermittent hypoxia, defined as alternating bouts of breathing hypoxic and normoxic air, has the potential to improve oxygen-carrying capacity through an erythropoietin-mediated increase in hemoglobin mass. The purpose of this study was to determine the effect of a single session of intermittent hypoxia on erythropoietin levels and hemoglobin mass in young healthy individuals. Nineteen participants were randomly assigned to an intermittent hypoxia group (Hyp, n = 10) or an intermittent normoxia group (Norm, n = 9). Intermittent hypoxia consisted of five 4-min hypoxic cycles at a targeted arterial oxygen saturation of 90% interspersed with 4-min normoxic cycles. Erythropoietin levels were measured before and two hours following completion of the protocol. Hemoglobin mass was assessed the day before and seven days after exposure to intermittent hypoxia or normoxia. As expected, the intermittent hypoxia group had a lower arterial oxygen saturation than the intermittent normoxia group during the intervention (Hyp: 89 ± 1 vs. Norm: 99 ± 1%, p < 0.01). Erythropoietin levels did not significantly increase following exposure to intermittent hypoxia (Hyp: 8.2 ± 4.5 to 9.0 ± 4.8, Norm: 8.9 ± 1.7 to 11.1 ± 2.1 mU·mL−1, p = 0.15). Hemoglobin mass did not change following exposure to intermittent hypoxia. This single session of intermittent hypoxia was not sufficient to elicit a significant rise in erythropoietin levels or hemoglobin mass in young healthy individuals.

Highlights

Cardiorespiratory fitness, assessed by measuring maximal oxygen consumption, represents the ability of the cardiovascular system to transport and use oxygen during maximal exercise.Oxygen transport from the lungs to the exercising muscles is achieved through the binding of oxygen to hemoglobin, an iron-containing protein in the red blood cell
Arterial oxygen saturation was lower during intermittent hypoxia than intermittent normoxia (Table 2), which was equivalent to a lower fraction of inspired oxygen (Table 3)
There was no difference between intermittent hypoxia and intermittent normoxia for any other hemodynamic or pulmonary gas exchange variables (Tables 2 and 3)

Summary

Introduction

Cardiorespiratory fitness, assessed by measuring maximal oxygen consumption, represents the ability of the cardiovascular system to transport and use oxygen during maximal exercise.Oxygen transport from the lungs to the exercising muscles is achieved through the binding of oxygen to hemoglobin, an iron-containing protein in the red blood cell. Cardiorespiratory fitness, assessed by measuring maximal oxygen consumption, represents the ability of the cardiovascular system to transport and use oxygen during maximal exercise. Hemoglobin mass represents the oxygen-carrying capacity of the blood and strongly correlates with maximal oxygen consumption [1]. Interventions that increase hemoglobin mass would improve the oxygen-carrying capacity and, maximal oxygen consumption. The development of novel interventions to improve oxygen-carrying capacity remains important for populations with limited exercise tolerance that do not meet recommended physical activity levels, such as patients with type 2 diabetes [2,3]. The combined observation of normal hematocrit levels with a lower blood volume indicates a reduced hemoglobin mass in patients with type 2 diabetes. A reduced oxygen-carrying capacity likely contributes to the lower maximal oxygen consumption consistently observed in patients with type 2 diabetes [5,6]

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