Exercise Capacity in Subjects With High Oxygen Affinity

Abstract

Exercise capacity and hemodynamic parameters were measured in ten patients with a previously unpublished variant of hemoglobin (Hb-Linköping) and in ten age- and sex-matched controls. Bicycle ergometer test was almost maximal and the indices of working capacity and cardiac tolerance were similar in patients and controls. The hemoglobin dissociation curve was shifted to the left at rest and after exercise the shift to right was half of the corresponding shift in controls. Lactate accumulation during exercise was similar in patients and controls, also the elimination rate seems identical, but requires further studies. Hydrogen ion production in the patients during exercise was more marked than in the controls. If this is a sign of altered energy metabolism remains to be ascertained in future studies. In acute short-term exercise the patients with abnormally high hemoglobin oxygen affinity seem to have similar tolerance and cardiovascular load. Aberrant metabolism and adaptation to relative hypoxia in spite of erythrocytosis may have long-term effects that require long-term follow-up of these patients.

Influence of High Hemoglobin-Oxygen Affinity on Humans During Hypoxia

“…In corroboration with results found through mathematical modeling, humans with high Hb-O 2 affinity show no difference in normoxic VO 2max values compared to similar age, sexmatched controls with normal Hb-O 2 affinity (Länsimies et al, 1985;Dominelli et al, 2020). However, there is evidence for altered metabolic processes among humans with high Hb-O 2 affinity compared to controls during exercise testing.…”

“…In addition to an elevated hematocrit humans with high Hb-O 2 affinity likely develop skeletal muscle adaptations to compromised O 2 offloading such as a greater percentage of non-oxidative (type II) muscle fibers than their counterparts with normal Hb-O 2 affinity (Wranne et al, 1983). Additionally, a greater accumulation of metabolic byproducts (e.g., lactate and H + ) during highintensity exercise have been reported in humans with high Hb-O 2 affinity compared to those with normal Hb-O 2 affinity (Länsimies et al, 1985;Dominelli et al, 2020). Those with high Hb-O 2 affinity demonstrate a similar lactate accumulation at the end of exhaustive exercise during both normoxia and hypoxia, whereas controls demonstrate a reduced lactate accumulation during hypoxia compared to normoxia (Dominelli et al, 2020).…”

“…However, there is evidence for altered metabolic processes among humans with high Hb-O 2 affinity compared to controls during exercise testing. During cycling exercise in normoxia, humans with high Hb-O 2 affinity may have greater reliance on anaerobic metabolism during heavy to maximal exercise, as evidenced by lower blood pH and pronounced lactate production compared to controls (Wranne et al, 1983;Länsimies et al, 1985;Dominelli et al, 2020). In addition, humans with high Hb-O 2 affinity seem to display a worsened exercise efficiency during cycling, i.e., higher O 2 consumption for a given power output (Dominelli et al, 2020).…”

Symptomatic Erythrocytosis Associated with a Compound Heterozygosity for Hb Lepore-Boston-Washington (δ87-β116) and Hb Johnstown [β109(G11)Val→Leu,GTG>TTG]

“…(12) measured the maximum work capacity in 10 individuals with Hb Linköping [β36(C2)Pro!Thr,FIGURE 4 DNA sequencing of the β-globin gene showed a mutation at codon 109 (GTG>TTG) (Val!Leu) confirming the Hb Johnstown variant. The δβ fusion variant Hb Lepore was not detected.368S.…”