Search Results

You are looking at 1 - 10 of 22 items for :

  • "erythropoiesis" x
  • All content x
Clear All
Restricted access

Nenad Ponorac, Mira Popović, Dea Karaba-Jakovljević, Zorislava Bajić, Aaron Scanlan, Emilija Stojanović, and Dragan Radovanović

Impaired iron status has been associated with typical symptoms, such as fatigue, lethargy, and negative mood states (Stage 1), and in more severe cases (e.g., iron-deficient erythropoiesis [IDE], iron deficiency anemia [IDA]), it compromises exercise capacity ( Sim et al., 2019 ). Although

Restricted access

Torben Pottgiesser, Laura A. Garvican, David T. Martin, Jesse M. Featonby, Christopher J. Gore, and Yorck O. Schumacher

Hemoglobin mass (tHb) is considered to be a main factor for sea-level performance after “live high–train low” (LHTL) altitude training, but little research has focused on the persistence of tHb following cessation of altitude exposure. The aim of the case study was to investigate short-term effects of various hematological measures including tHb upon completion of a simulated altitude camp. Five female cyclists spent 26 nights at simulated altitude (LHTL, 16.6 ± 0.4 h/d, 3000 m in an altitude house) where tHb was measured at baseline, at cessation of the camp, and 9 d thereafter. Venous blood measures (hemoglobin concentration, hematocrit, %reticulocytes, serum erythropoietin, ferritin, lactate dehydrogenase, and haptoglobin) were determined at baseline; on day 21 during LHTL; and at days 2, 5, and 9 after LHTL. Hemoglobin mass increased by 5.5% (90% confidence limits [CL] 2.5 to 8.5%, very likely) after the LHTL training camp. At day 9 after simulated LHTL, tHb decreased by 3.0% (90%CL −5.1 to −1.0%, likely). There was a substantial decrease in serum EPO (−34%, 90%CL −50 to −12%) at 2 d after return to sea level and a rise in ferritin (23%, 90%CL 3 to 46%) coupled with a decrease in %reticulocytes (−23%, 90%CL −34 to −9%) between day 5 and 9 after LHTL. Our findings show that following a hypoxic intervention with a beneficial tHb outcome, there may be a high probability of a rapid tHb decrease upon return to normoxic conditions. This highlights a rapid component in red-cell control and may have implications for the appropriate timing of altitude training in relation to competition.

Restricted access

Laura A. Garvican, Louisa Lobigs, Richard Telford, Kieran Fallon, and Christopher J. Gore

Haemoglobin mass in a female endurance athlete was measured via carbon monoxide rebreathing upon diagnosis of iron-deficiency anemia (haemoglobin concentration = 8.8 g/dL, ferritin = 9.9 ng/mL) and regularly during treatment thereafter. Haemoglobin mass increased by 49% in the 2 wk following an intramuscular iron injection and continued to increase with oral iron supplementation for 15 wk. The presented case illustrates that haemoglobin mass is readily responsive to iron supplementation in a severely iron-defcient anemic athlete and that changes can be tracked efficiently using the CO-rebreathing method.

Restricted access

Mitsuo Neya, Taisuke Enoki, Nao Ohiwa, Takashi Kawahara, and Christopher J. Gore


To quantify the changes of hemoglobin mass (Hbmass) and maximum oxygen consumption (VO2max) after 22 days training at 1300–1800 m combined with nightly exposure to 3000-m simulated altitude. We hypothesized that with simulated 3000-m altitude, an adequate beneficial dose could be as little as 10 h/24 h.


Fourteen male collegiate runners were equally divided into 2 groups: altitude (ALT) and control (CON). Both groups spent 22 days at 1300–1800 m. ALT spent 10 h/night for 21 nights in simulated altitude (3000 m), and CON stayed at 1300 m. VO2max and Hbmass were measured twice before and once after the intervention. Blood was collected for assessment of percent reticulocytes (%retics), serum erythropoietin (EPO), ferritin, and soluble transferrin receptor (sTfR) concentrations.


Compared with CON there was an almost certain increase in absolute VO2max (8.6%, 90% confidence interval 4.8–12.6%) and a likely increase in absolute Hbmass (3.5%; 0.9–6.2%) at postintervention. The %retics were at least very likely higher in ALT than in CON throughout the 21 nights, and sTfR was also very likely higher in the ALT group until day 17. EPO of ALT was likely higher than that of CON on days 1 and 5 at altitude, whereas serum ferritin was likely lower in ALT than CON for most of the intervention.


Together the combination of the natural and simulated altitude was a sufficient total dose of hypoxia to increase both Hbmass and VO2max.

Restricted access

Gordon Sleivert, Val Burke, Craig Palmer, Alan Walmsley, David Gerrard, Stephen Haines, and Roger Littlejohn

To determine the effects of deer antler velvet on maximal aerobic performance and the trainability of muscular strength and endurance, 38 active males were randomly assigned in a double-blind fashion to either deer antler velvet extract (n = 12), powder (n = 13), or placebo groups (n = 13). Subjects were tested prior to beginning supplementation and a 10-week strength program, and immediately post-training. All subjects were measured for circulating levels of testosterone, insulin-like growth factor, erythropoietin, red cell mass, plasma volume, and total blood volume. Additionally, muscular strength, endurance, and VO2max were determined. All groups improved 6 RM strength equivalently (41 ± 26%, p < .001), but there was a greater increase in isokinetic knee extensor strength (30 ± 21% vs. 13 ± 15%, p = .04) and endurance (21 ± 19% vs. 7 ± 12%, p = .02) in the powder compared to placebo group. There were no endocrine, red cell mass or VO2max changes in any group. These findings do not support an erythropoetic or aerobic ergogenic effect of deer antler velvet. Further, the inconsistent findings regarding the effects of deer antler velvet powder supplementation on the development of strength suggests that further work is required to test the robustness of the observation that this supplement enhances the strength training response and to ensure this observation is not a type I error.

Restricted access

Malcolm T. Whitehead, Tyler D. Martin, Timothy P. Scheett, and Michael J. Webster

The purpose of this investigation was to determine whether echinacea supplementation results in alterations of erythroid growth factors and erythropoietic status. Twenty-four men age 24.9 ± 4.2 y, height 1.7 ± 0.8 m, weight 87.9 ± 14.6 kg, and 19.3% ± 6.5% body fat were grouped using a double-blind design and self-administered an 8000-mg/d dose of either echinacea (ECH) or placebo (PLA) in 5 × 400 mg × 4 times/d for 28 d. Blood samples were collected and analyzed for red blood cells (RBCs), hematocrit (Hct), hemoglobin (Hb), mean corpuscular volume, mean corpuscular hemoglobin content, prostaglandin E2, ferritin, erythropoietin (EPO), interleukin 3 (IL-3), and granulocyte-macrophage-colony-stimulating factor using automated flow cytometry and ELISA. ANOVA was used to determine significant differences (P ≤ 0.05). EPO was greater (P < 0.001) in ECH at Days 7, 14, and 21 and refected a 44%, 63%, and 36% increase, respectively. IL-3 was greater (P = 0.011) in ECH at Days 14 and 21, which indicated a 65% and 73% increase, respectively. These data indicate that ECH supplementation resulted in an increase in EPO and IL-3 but did not significantly alter RBCs, Hb, or Hct.

Restricted access

John D. Robertson, Ronald J. Maughan, Ann C. Milne, and Ronald J.L. Davidson

Blood biochemical indices of iron status were measured in venous blood from 20 runners and 6 control subjects. All subjects were.male, ages 20 to 40 years, and stable with regard to body weight and degree of physical activity. Dietary analysis was undertaken using a 7-day weighed food intake. There was no evidence of iron deficiency: hemoglobin concentrations and serum femtin levels were within the normal population range for all individuals. However, serum ferritin was negatively correlated with the amount of training. Daily iron intake appeared to be adequate; iron intake was correlated with protein intake but not related to training or energy intake. Serum ferritin, an indicator of iron status, was significantly correlated with vitamin C intake but not iron intake. Serum transferrin concentration was higher in the group of athletes undertaking a high weekly training load compared with the control subjects, suggesting an alteration in iron metabolism although there was no evidence of increased erythropoiesis. The biological significance of this is unclear.

Restricted access

Jadwiga Malczewska, Beata Szczepańska, Romuald Stupnicki, and Witold Sendecki

The transferrin receptor-ferritin index (sTfR/logFerr) was determined in 131 male and 121 female athletes in order to assess the frequency of iron deficiency (threshold value of that index taken as 1.8). Blood was drawn for determining morphological indices as well as sTfR, ferritin, iron, total iron binding capacity (TIBC), and haptoglobin. A significantly (p < .01) higher incidence of iron deficiency was observed in women (26%) than in men (11%). The iron deficiency was latent, since no subject was found to be anemic. The plasma iron was significantly lower and TIBC higher (p < .001) in both iron-deficient subgroups than in the non-deficient ones. This confirmed the latent character of iron deficiency. Some hematological indices (Hb, MCH, MCHC, MCV) were significantly lower in iron-deficient female athletes than in male athletes, which suggested a more profound iron deficiency in the former. The sTfR/logFerr index might thus be useful in detecting iron deficiency in athletes, especially in those with erythropoiesis disorders, since physical loads may affect the widely used ferritin levels.

Restricted access

13 13 3 3 The Effects of Deer Antler Velvet Extract or Powder Supplementation on Aerobic Power, Erythropoiesis, and Muscular Strength and Endurance Characteristics Gordon Sleivert * Val Burke * Craig Palmer * Alan Walmsley * David Gerrard * Stephen Haines * Roger Littlejohn * 9 2003

Restricted access

. Shepherd * Hunter S. Waldman * Matthew J. McAllister * JohnEric W. Smith * 1 01 2020 30 1 42 47 10.1123/ijsnem.2019-0073 ijsnem.2019-0073 Professional Female Athletes Are at a Heightened Risk of Iron-Deficient Erythropoiesis Compared With Nonathletes Nenad Ponorac * Mira Popović * Dea Karaba