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Strenuous physical training increases total blood volume (BV) through expansion of plasma volume (PV) and red cell volume (RCV). In contrast, exogenous erythropoietin (EPO) treatment increases RCV but decreases PV, rendering BV stable or slightly decreased. This study aimed to determine the combined effects of strenuous training and EPO treatment on BV and markers of systemic and muscle iron homeostasis. In this longitudinal study, eight healthy nonanemic males were treated with EPO (50 IU/kg body mass, three times per week, sc) across 28 days of strenuous training (4 days/wk, exercise energy expenditures of 1,334 ± 24 kcal/day) while consuming a controlled, energy-balanced diet providing 39 ± 4 mg/day iron. Before (PRE) and after (POST) intervention, BV compartments were measured using carbon monoxide rebreathing, and markers of iron homeostasis were assessed in blood and skeletal muscle (vastus lateralis). Training + EPO increased ( P < 0.01) RCV (13 ± 6%) and BV (5 ± 4%), whereas PV remained unchanged ( P = 0.86). The expansion of RCV was accompanied by a large decrease in whole body iron stores, as indicated by decreased ( P < 0.01) ferritin (-77 ± 10%) and hepcidin (-49 ± 23%) concentrations in plasma. Training + EPO decreased ( P < 0.01) muscle protein abundance of ferritin (-25 ± 20%) and increased ( P < 0.05) transferrin receptor (47 ± 56%). These novel findings illustrate that strenuous training combined with EPO results in both increased total oxygen-carrying capacity and hypervolemia in young healthy males. The decrease in plasma and muscle ferritin suggests that the marked upregulation of erythropoiesis alters systemic and tissue iron homeostasis, resulting in a decline in whole body and skeletal muscle iron stores. NEW & NOTEWORTHY Strenuous exercise training combined with erythropoietin (EPO) treatment increases blood volume, driven exclusively by red cell volume expansion. This hematological adaptation results in increased total oxygen-carrying capacity and hypervolemia. The marked upregulation of erythropoiesis with training + EPO reduces whole body iron stores and circulating hepcidin concentrations. The finding that the abundance of ferritin in muscle decreased after training + EPO suggests that muscle may release iron to support red blood cell production.

Dietary nitrate (NO 3 - ) supplementation is known to enhance nitric oxide (NO) activity and acts as a vasodilator. In this randomized crossover study, we investigated the effect of inorganic NO 3 - supplementation on the changes in calf venous volume during postural change and subsequent skeletal muscle pump activity. Fifteen healthy young adults were assigned to receive beetroot juice (BRJ) or a NO 3 - -depleted control beverage (prune juice: CON). Two hours after beverage consumption, the changes in the right calf volume during postural change from supine to upright and a subsequent right tiptoe maneuver were measured using venous occlusion plethysmography. The increase in calf volume from the supine to upright position (total venous volume [VV]) and the decrease in calf volume during the right tiptoe maneuver (venous ejection volume [Ve]) were calculated. Plasma NO 3 - concentration was higher in the BRJ group than in the CON group 2 h after beverage intake ( p < 0.05). However, VV and Ve did not differ between CON and BRJ. These results suggest that acute intake of BRJ may enhance NO activity via the NO 3 - → nitrite → NO pathway but does not change calf venous pooling due to a postural change or the calf venous return due to skeletal muscle pump activity in healthy young adults.

A safe induction method of general anaesthesia for paediatric moyamoya disease patients has not been fully established. We had the opportunity to administer general anaesthesia twice to a two-year-old girl diagnosed with moyamoya disease. We used different induction methods for general anaesthesia at each session, i.e. slow induction with sevoflurane and rapid induction with propofol, and were able to evaluate changes in her left regional cortical blood volume (rCBV) and oxygenation (rCBO) during both anaesthesia inductions using near-infrared spectroscopy (NIRS). The mean change value of total-Hb (rCBV) (mean ± SD; μmol/L) in the rapid induction was lower than that in the slow induction (-0.54 ± 1.43 vs. 1.82 ± 1.74). However, the TOI (rCBO) levels during both anaesthesia inductions were constantly higher than these respective baseline values (64% in the slow induction, 71% in the rapid induction), and these mean change values in each of the anaesthesia induction were about the same. The present results suggested that both the slow induction method with sevoflurane and the rapid induction method with propofol might be safe and effective for anaesthesia induction in paediatric patients with moyamoya disease., (© 2024. Oxygen Transport to Tissue International.)