Hemoglobin Mass and Peak Oxygen Uptake in Untrained and Trained Female Altitude Residents

Abstract

Total hemoglobin mass has not been systematically investigated in females at altitude. We measured this quantity (CO-rebreathing method) as well as peak oxygen uptake in 54 young women (age 22.5 +/- 0.6 SE years) with differing physical fitness living in Bogota (2600 m) and compared the results with those of 19 subjects from 964 m in Colombia and 75 subjects from 35 m in Germany. In spite of an increased hemoglobin concentration the hemoglobin mass was not changed in highlanders (means 9.0 to 9.5 g . kg (-1) in untrained subjects at all altitude levels). Endurance trained athletes, however, showed a rise in hemoglobin mass by 2 - 3 g . kg (-1) at all sites. Erythropoietin was little increased in Bogota; iron stores were within the normal range. Aerobic performance capacity was lower at high altitude than at sea level and remained so also after correction for the hypoxic deterioration in untrained and moderately trained subjects but not in athletes; possibly the cause was reduced daily physical activity in non-athletic Bogotanians compared to lowlanders. After exclusion of the factor V.O(2peak) by analysis of covariance a mean rise of 6.6 % in hemoglobin mass at 2600 m was calculated being smaller than in males (> 12 %). The attenuated increase of hemoglobin mass in female highlanders possibly results from stimulation of ventilation improving arterial oxygen saturation or from an increased hypoxia tolerance of cellular metabolism both caused by female sexual hormones.

Diurnal changes of arterial oxygen saturation and erythropoietin concentration in male and female highlanders

“…When comparing residents in Berlin (30 m above sea level) and Bogotá (Böning et al. , ), there is even a tendency for an increased arterial oxygen content in Bogotá at approximately 08:00: 20.1 and 21.7 mL/dL for males, 16.7 and 18.0 mL/dL for females. Additionally, the oxygen dissociation curve is slightly right‐shifted in Bogotá (approx.…”

“…); at 2600 m, about half of the investigated young male and female inhabitants show values below the threshold (Böning et al. , ).…”

“…The [Epo] increase was also small or absent at 2600 m in Bogotá (Böning et al. , ; Schmidt et al. ; Cristancho et al.…”

“…Ventilatory stimulation by female sex hormones might cause a reduced decrease of SaO 2 in women at altitude (Böning et al. , ; Cristancho et al. ).…”

Effects of various training modalities on blood volume

“…His increase in tHb‐mass by 18.3% within 3 weeks at 2100 m (mean of the group+7.2%) was accompanied by lower Hb–O 2 ‐saturation, right shifted oxygen dissociation curve, and higher EPO concentration. Reasons for a missing response to altitude may be a high hypoxic ventilatory response (HVR) as it is typical for females rather than for males (Böning et al, 2004) as well as the inhibition of erythropoiesis due to inflammatory diseases or a lack of iron availability.…”