Chronic Exposure to Low-Dose Carbon Monoxide Alters Hemoglobin Mass and V˙O2max

Abstract

By blocking the oxygen binding sites on the hemoglobin molecule, chronic low-dose carbon monoxide (CO) administration may produce similar effects to those of exposure to altitude. Purpose This study aimed to determine the effect of chronic low-dose CO application on hemoglobin mass (Hbmass) and V˙O2max. Methods For 3 wk, 11 healthy and moderately trained male subjects inhaled a CO bolus five times per day to increase their HbCO concentration by ~5%. Another 11 subjects received a placebo. Hbmass, serum erythropoietin concentration, ferritin, and basic hematological parameters were determined before and weekly during and until 3 wk after the CO inhalation period. V˙O2max tests on a cycle ergometer were performed before and after the CO administration period. Results In the CO group, Hbmass increased from 919 ± 69 to 962 ± 78 g in week 3 (P < 0.001) and was maintained for the following 3 wk. Reticulocytes (%) and immature reticulocyte fraction significantly increased after 1 wk. Serum erythropoietin concentration tended to increase after 1 wk (P = 0.07) and was suppressed in the postperiod (P < 0.01). Ferritin decreased during the inhalation period (from 106 ± 37 to 72 ± 37 ng·mL−1, P < 0.001). V˙O2max tended to increase from 4230 ± 280 to 4350 ± 350 mL·min−1 (P < 0.1) immediately after the inhalation period and showed a significant relationship to the change in Hbmass (y = 4.1x − 73.4, r = 0.70, P < 0.001). Conclusions Chronic continuous exposure to low-dose CO enhances erythropoietic processes resulting in a 4.8% increase in Hbmass. The individual changes in Hbmass were correlated to the corresponding changes in V˙O2max. Examination of ethical and safety concerns is warranted before the implementation of low-dose CO inhalation in the clinical/athletic setting as a tool for modifying Hbmass.

A carbon monoxide ‘single breath’ method to measure total haemoglobin mass: a feasibility study

“…In the literature, there has also been extensive debate about the merits of having a higher [ΔCOHb%] versus the increased toxicity risk (Alexander et al., 2011; Garvican et al., 2010; Turner et al., 2014). [COHb] of up to 10% has been described without remarkable side effects in healthy subjects (Schmidt et al., 2020), but to our knowledge, it has never been studied in seriously ill patients. Because CO is endogenously produced and is actually considered for the treatment of various diseases (Motterlini & Otterbein, 2010), we are convinced that the increase in COHb by 4–5%, as achieved in our study, represents a reliable compromise balancing sources of error with minimal patient risk.…”

Impact of Exposure to Carbon Monoxide on COHb Levels and Health Problems on Swords and Parking Attendants in A Parking Area at the Bandar Lampung Market, Indonesia

“…Continuous exposure associated with a long duration of action at low doses can enhance the erythropoietic process with a 4.8% increase in Hbmass. Individual changes in Hbmass correlate with corresponding changes in VO 2 max [11].…”

Factors confounding the athlete biological passport: a systematic narrative review

“…Following blood transfusions, an increase in [Hb] combined with a decrease in Ret% was generally reported after blood withdrawal while the opposite effect occurred during re-infusion [16,44]. In addition, chronic exposure to low doses of carbon monoxide was recently shown to positively influence erythropoiesis and alter markers sensitive to PV variations [46,95]. Conversely, repeated intake of desmopressin or chronic xenon inhalation induced haemodilution and decreased concentration-based biomarkers sensitive to PV shift [39,47,96].…”