Effect of Repeated Whole Blood Donations on Aerobic Capacity and Hemoglobin Mass in Moderately Trained Male Subjects: A Randomized Controlled Trial

L-Arginine and Nitric Oxide in Vascular Regulation-Experimental Findings in the Context of Blood Donation

This narrative review provides an analysis of the role of nitric oxide (NO) and its precursors, particularly L-arginine, in vascular regulation and health, with an emphasis on findings from our experimental research in animal models. NO serves as a critical mediator of vascular function, contributing to vasodilation, the regulation of blood flow, and the prevention of thrombosis. As a primary precursor of NO, L-arginine is essential for maintaining endothelial integrity, modulating mitochondrial function, and reducing oxidative damage. This review synthesises the data and contextualises these findings within the physiological challenges faced by blood donors, such as repeated blood donation and associated oxidative stress. It examines the effects of L-arginine supplementation on mitochondrial respiration, lipid peroxidation, and microsomal oxidation in different conditions, including differences in age, gender, and dietary interventions. The mechanisms by which L-arginine enhances NO production, improves vascular elasticity, and alleviates endothelial dysfunction caused by reduced NO bioavailability are also investigated. By integrating experimental findings with insights from the existing literature, this review provides a perspective on the potential of L-arginine supplementation to address the specific physiological needs of blood donors. It highlights the importance of personalised nutritional approaches in enhancing donor recovery and vascular resilience. In addition, this review assesses the wider implications of L-arginine supplementation in mitigating oxidative stress and preserving vascular function. The interplay between NO bioavailability, dietary factors, and physiological adaptation in blood donors is highlighted, along with the identification of current knowledge gaps and recommendations for future research. By presenting both original experimental evidence and a critical synthesis of the literature, this article highlights the therapeutic potential of NO precursors, particularly L-arginine, in promoting vascular health in the context of blood donation.

Effects of plasmapheresis frequency on health status and exercise performance in men: A randomized controlled trial

BACKGROUND AND OBJECTIVES

Most research studies on the effects of repeated plasma donation are observational with different study limitations, resulting in high uncertainty on the link between repeated plasma donation and health consequences. Here, we prospectively investigated the safety of intensive or less intensive plasma donation protocols.

MATERIALS AND METHODS

Sixty-three male subjects participated in this randomized controlled trial and were divided into low-frequency (LF, once/month, n = 16), high-frequency (HF, three times/month, n = 16), very high-frequency (VHF, two times/week, n = 16) and a placebo (P, once/month, n = 15) groups. Biochemical, haematological, clinical, physiological and exercise-related data were collected before (D0), after 1½ months (D42) and after 3 months (D84) of donation.

RESULTS

In VHF, red blood cells, haemoglobin and haematocrit levels decreased while reticulocyte levels increased from D0 to D84. In both HF and VHF, plasma ferritin levels were lower at D42 and D84 compared to D0. In VHF, plasma levels of albumin, immunoglobulin G (IgG), immunoglobulin A (IgA) and immunoglobulin M (IgM) dropped from D0 to D42 and remained lower at D84 than at D0. In HF, plasma IgG, IgA and IgM were lower at D42, and IgG and IgM were lower at D84, compared to D0. Few adverse events were reported in HF and VHF. Repeated plasma donation had no effect on blood pressure, body composition or exercise performance.

CONCLUSION

VHF plasmapheresis may result in a large reduction in ferritin and IgG levels. HF and VHF plasmapheresis may result in little to no difference in other biochemical, haematological, clinical, physiological and exercise-related parameters.

Clonal hematopoiesis in frequent whole blood donors

Healthy volunteer donors are committed to contributing key medical resources. Repeated, regular donation of whole blood represents a specific trigger of hematopoietic stress. Hematopoietic stem cells (HSCs) are known to respond to environmental triggers by altering their differentiation and/or proliferative behavior. This can manifest in long-term changes in the clonal dynamics of HSCs, such as the age-associated expansion of HSCs carrying somatic mutations in genes associated with hematologic cancers-that is, clonal hematopoiesis (CH). A recent study revealed a higher prevalence of CH in frequent donors driven by low-risk mutations in genes encoding for epigenetic modifiers, with DNMT3A and TET2 being the most common. No difference in the prevalence of known preleukemic driver mutations was detected between the cohorts, underscoring the safety of repetitive blood donations. Functional analyses suggest a link between the presence of selected DNMT3A mutations found in the frequent donor group and the responsiveness of the cells to the molecular mediator of bleeding stress, erythropoietin (EPO), but not inflammation. These findings define EPO as one of the environmental factors that provide a fitness advantage to specific mutant HSCs. Analyzing CH prevalence and characteristics in other donor cohorts will be important to comprehensively assess the health risks associated with the different types of donation.

The relationship between hemoglobin and V ˙ ⁢ O 2 ⁢ m ⁢ a ⁢ x : A systematic review and meta-analysis

OBJECTIVE

There is widespread agreement about the key role of hemoglobin for oxygen transport. Both observational and interventional studies have examined the relationship between hemoglobin levels and maximal oxygen uptake (V ˙ ⁢ O 2 ⁢ m ⁢ a ⁢ x ) in humans. However, there exists considerable variability in the scientific literature regarding the potential relationship between hemoglobin andV ˙ ⁢ O 2 ⁢ m ⁢ a ⁢ x . Thus, we aimed to provide a comprehensive analysis of the diverse literature and examine the relationship between hemoglobin levels (hemoglobin concentration and mass) andV ˙ ⁢ O 2 ⁢ m ⁢ a ⁢ x (absolute and relativeV ˙ ⁢ O 2 ⁢ m ⁢ a ⁢ x ) among both observational and interventional studies.

METHODS

A systematic search was performed on December 6th, 2021. The study procedures and reporting of findings followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Article selection and data abstraction were performed in duplicate by two independent reviewers. Primary outcomes were hemoglobin levels andV ˙ ⁢ O 2 ⁢ m ⁢ a ⁢ x values (absolute and relative). For observational studies, meta-regression models were performed to examine the relationship between hemoglobin levels andV ˙ ⁢ O 2 ⁢ m ⁢ a ⁢ x values. For interventional studies, meta-analysis models were performed to determine the change inV ˙ ⁢ O 2 ⁢ m ⁢ a ⁢ x values (standard paired difference) associated with interventions designed to modify hemoglobin levels orV ˙ ⁢ O 2 ⁢ m ⁢ a ⁢ x . Meta-regression models were then performed to determine the relationship between a change in hemoglobin levels and the change inV ˙ ⁢ O 2 ⁢ m ⁢ a ⁢ x values.

RESULTS

Data from 384 studies (226 observational studies and 158 interventional studies) were examined. For observational data, there was a positive association between absoluteV ˙ ⁢ O 2 ⁢ m ⁢ a ⁢ x and hemoglobin levels (hemoglobin concentration, hemoglobin mass, and hematocrit (P<0.001 for all)). Prespecified subgroup analyses demonstrated no apparent sex-related differences among these relationships. For interventional data, there was a positive association between the change of absoluteV ˙ ⁢ O 2 ⁢ m ⁢ a ⁢ x (standard paired difference) and the change in hemoglobin levels (hemoglobin concentration (P<0.0001) and hemoglobin mass (P = 0.006)).

CONCLUSION

These findings suggest thatV ˙ ⁢ O 2 ⁢ m ⁢ a ⁢ x values are closely associated with hemoglobin levels among both observational and interventional studies. Although our findings suggest a lack of sex differences in these relationships, there were limited studies incorporating females or stratifying results by biological sex.

Autologous Blood Doping Induced Changes in Red Blood Cell Rheologic Parameters, RBC Age Distribution, and Performance

Simple Summary

Autologous blood doping (ABD) refers to the artificial increase in circulating red blood cell (RBC) mass by sampling, storage, and transfusion of one’s own blood. It is assumed that some athletes apply this prohibited technique to improve oxygen transport capacity and thus exercise performance. The primary aim of this study was to test whether RBC rheological and associated parameters significantly change due to ABD with the consideration of whether this type of measurement might be suitable for detecting ABD. Further, it was assessed whether those changes are translated into indices of endurance performance. Eight males underwent an ABD protocol combined with several blood parameter measurements and two exercise tests (pre and post transfusion). Results of this investigation suggest a change in the distribution of age-related RBC sub-populations and altered deformability of total RBC as well as of the respective sub-populations. Further, the identified changes in RBC also appear to improve sports performance. In conclusion, these data demonstrate significant changes in hematological and hemorheological parameters, which could be of interest in the context of new methods for ABD detection. However, additional research is needed with larger and more diverse study groups to widen the knowledge gained by this study.

Abstract

Autologous blood doping (ABD) refers to the transfusion of one’s own blood after it has been stored. Although its application is prohibited in sports, it is assumed that ABD is applied by a variety of athletes because of its benefits on exercise performance and the fact that it is not detectable so far. Therefore, this study aims at identifying changes in hematological and hemorheological parameters during the whole course of ABD procedure and to relate those changes to exercise performance. Eight healthy men conducted a 31-week ABD protocol including two blood donations and the transfusion of their own stored RBC volume corresponding to 7.7% of total blood volume. Longitudinal blood and rheological parameter measurements and analyses of RBC membrane proteins and electrolyte levels were performed. Thereby, responses of RBC sub-populations—young to old RBC—were detected. Finally, exercise tests were carried out before and after transfusion. Results indicate a higher percentage of young RBC, altered RBC deformability and electrolyte concentration due to ABD. In contrast, RBC membrane proteins remained unaffected. Running economy improved after blood transfusion. Thus, close analysis of RBC variables related to ABD detection seems feasible but should be verified in further more-detailed studies.

Differences in Cardiac Output and Aerobic Capacity Between Sexes Are Explained by Blood Volume and Oxygen Carrying Capacity

Whether average sex differences in cardiorespiratory fitness can be mainly explained by blood inequalities in the healthy circulatory system remains unresolved. This study evaluated the contribution of blood volume (BV) and oxygen (O₂) carrying capacity to the sex gap in cardiac and aerobic capacities in healthy young individuals. Healthy young women and men (n = 28, age range = 20–43 years) were matched by age and physical activity. Echocardiography, blood pressures, and O₂ uptake were measured during incremental exercise. Left ventricular end-diastolic volume (LVEDV), stroke volume (SV), cardiac output (Q), peak O₂ uptake (VO_2peak), and BV were assessed with precise methods. The test was repeated in men after blood withdrawal and reduction of O₂ carrying capacity, reaching women’s levels. Before blood normalization, exercise cardiac volumes and output (LVEDV, SV, Q) adjusted by body size and VO_2peak (42 ± 9 vs. 50 ± 11 ml⋅min^–1⋅kg^–1, P < 0.05) were lower in women relative to men. Blood normalization abolished sex differences in cardiac volumes and output during exercise (P ≥ 0.100). Likewise, VO_2peak was similar between women and men after blood normalization (42 ± 9 vs. 40 ± 8 ml⋅min^–1⋅kg^–1, P = 0.416). In conclusion, sex differences in cardiac output and aerobic capacity are not present in experimental conditions matching BV and O₂ carrying capacity between healthy young women and men.

Blood withdrawal acutely impairs cardiac filling, output and aerobic capacity in proportion to induced hypovolemia in middle-aged and older women

Blood donation entails acute reductions of cardiorespiratory fitness in healthy men. Whether these effects can be extrapolated to blood donor populations comprising women remains uncertain. The purpose of this study was to comprehensively assess the acute impact of blood withdrawal on cardiac function, central hemodynamics and aerobic capacity in women throughout the mature adult lifespan. Transthoracic echocardiography and O2 uptake were assessed at rest and throughout incremental exercise (cycle ergometry) in healthy women (n = 30, age: 47-77 yr). Left ventricular end-diastolic volume (LVEDV), stroke volume (SV), cardiac output (Q̇) and peak O2 uptake (V̇O2peak), and blood volume (BV) were determined with established methods. Measurements were repeated following a 10% reduction of BV within a week period. Individuals were non-smokers, non-obese and moderately fit (V̇O2peak = 31.4 ± 7.3 mL·min-1·kg-1). Hematocrit and BV ranged from 38.0 to 44.8% and from 3.8 to 6.6 L, respectively. The standard 10% reduction in BV resulted in 0.5 ± 0.1 L withdrawal of blood, which did not alter hematocrit (P = 0.953). Blood withdrawal substantially reduced cardiac LVEDV and SV at rest as well as during incremental exercise (≥10% decrements, P ≤ 0.009). Peak Q̇ was proportionally decreased after blood withdrawal (P < 0.001). Blood withdrawal induced a 10% decrement in V̇O2peak (P < 0.001). In conclusion, blood withdrawal impairs cardiac filling, Q̇ and aerobic capacity in proportion to the magnitude of hypovolemia in healthy mature women. Novelty: The filling of the heart and therefore cardiac output are impaired by blood withdrawal in women. Oxygen delivery and aerobic capacity are reduced in proportion to blood withdrawal.

Factors Confounding the Athlete Biological Passport: A Systematic Narrative Review

BACKGROUND

Through longitudinal, individual and adaptive monitoring of blood biomarkers, the haematological module of the athlete biological passport (ABP) has become a valuable tool in anti-doping efforts. The composition of blood as a vector of oxygen in the human body varies in athletes with the influence of multiple intrinsic (genetic) or extrinsic (training or environmental conditions) factors. In this context, it is fundamental to establish a comprehensive understanding of the various causes that may affect blood variables and thereby alter a fair interpretation of ABP profiles.

METHODS

This literature review described the potential factors confounding the ABP to outline influencing factors altering haematological profiles acutely or chronically.

RESULTS

Our investigation confirmed that natural variations in ABP variables appear relatively small, likely-at least in part-because of strong human homeostasis. Furthermore, the significant effects on haematological variations of environmental conditions (e.g. exposure to heat or hypoxia) remain debatable. The current ABP paradigm seems rather robust in view of the existing literature that aims to delineate adaptive individual limits. Nevertheless, its objective sensitivity may be further improved.

CONCLUSIONS

This narrative review contributes to disentangling the numerous confounding factors of the ABP to gather the available scientific evidence and help interpret individual athlete profiles.

An Analysis of Exertional Safety After Blood Donation in Active Duty Military Personnel-A Feasibility Study

INTRODUCTION

Whole blood (WB) is the optimal resuscitation fluid in hemorrhagic shock. Military research focuses on mortality benefits of WB acquired through walking blood banks (WBBs). Few military-based studies on donation effects exist, almost exclusively performed on small special operation forces. No Department of Defense regulations for postdonation precautions in nonaviation crew members exist. Further study is warranted regarding safety and limitations in postdonation populations.

MATERIALS AND METHODS

A feasibility (n = 25) prospective interventional study examined the safety of exertion (defined as a 1.6-km treadmill run at volunteers' minimum passing pace for the Army Physical Fitness Test) following 1 unit of WB donation. Subjects served as their own controls, performing baseline testing 7 days before donation, with repeat testing 1 h following donation conducted by Armed Services Blood Program personnel. Adverse events, pre- and postexertion vital signs (VS) were evaluated.

RESULTS

There were no adverse events throughout testing. Only resting heart rate (68 vs. 73 beats · min-1, p < 0.01) and postexertion heart rate were significantly different among pre- and postdonation VS. Additional significant findings were time to attain postexertion normocardia (116 vs. 147 seconds, p < 0.01). A small but statistically significant change in Borg perceived exertional scores was noted (10.3 vs. 10.8, p < 0.05).

CONCLUSIONS

This feasibility study demonstrates the first safety test of regular military populations performing exertion immediately following the standardized WB donation. VS changes may translate into a small but significant increase in perceived postdonation exertion. Future studies should expand duration and intensity of exertion to match combat conditions.

Indian blood donor selection guidelines: Review in the context of the ongoing COVID-19 pandemic

The National Blood Transfusion Services under the aegis of the ministry of health and family welfare, India has recently issued guidelines regarding the blood donor selection criteria and the processing of blood. Care has been taken to make the blood transfusions safer. However, COVID-19 has disrupted the organization of the voluntary blood donation drives, whole blood donations [WBD] and restricted the donors' movement to the blood transfusion centres all across the world. While sickness and the need for transfusions are very much in place, the gap of demand against blood collection has widened. Additionally, with the monsoon season at hand, and the categorical challenges of a dengue outbreak, the subsequent need for blood components especially the platelet concentrates is going to rise. Some of the criteria laid for deferring a blood donor from his or her WBD need a categorical revision, considering these unprecedented times. We, therefore, critically analyzed the blood donor selection criteria and hereby, suggest an updating regarding the pre-donation haemoglobin, sexually transmitted diseases, lactation, pregnancy and many such subheadings. We also suggest collecting smaller blood volumes in the blood bags for the optimal benefit of the recipients both for now and also as a measure of pandemic preparedness for future use.

Effects of Sprint Interval Training at Different Altitudes on Cycling Performance at Sea-Level

BACKGROUND

Benefits of sprint interval training performed in hypoxia (SIH) compared to normoxia (SIN) have been assessed by studies mostly conducted around 3000 m of simulated altitude. The present study aims to determine whether SIH at an altitude as high as 4000 m can elicit greater adaptations than the same training at 2000 m, 3000 m or sea-level.

METHODS

Thirty well-trained endurance male athletes (18-35 years old) participated in a six-week repeated sprint interval training program (30 s all-out sprint, 4 min 30 s recovery; 4-9 repetitions, 2 sessions/week) at sea-level (SL, n = 8), 2000 m (FiO2 16.7%, n = 8), 3000 m (FiO2 14.5%, n = 7) or 4000 m (FiO2 13.0%, n = 7). Aerobic and anaerobic exercise components were evaluated by an incremental exercise test, a 600 kJ time trial and a Wingate test before and after the training program.

RESULTS

After training, peak power output (PPO) during the incremental exercise test increased (~6%) without differences between groups. The lactate threshold assessed by Dmax increased at 2000 m (+14 ± 12 W) and 4000 m (+12 ± 11 W) but did not change at SL and 3000 m. Mean power during the Wingate test increased at SL, 2000 m and 4000 m, although peak power increased only at 4000 m (+38 ± 38 W).

CONCLUSIONS

The present study indicates that SIH using 30 s sprints is as efficient as SIN for improving aerobic and anaerobic qualities. Additional benefits such as lactate-related adaptations were found only in SIH and Wingate peak power only increased at 4000 m. This finding is of particular interest for disciplines requiring high power output, such as in very explosive sports.

Iron supplementation limits the deleterious effects of repeated blood donation on endurance sport performance but not on iron status

BACKGROUND

Every day, blood banks worldwide face the challenge of ensuring an adequate blood supply. Iron deficiency is by far the most common cause of deferral of blood donors. The aim of the present study was to determine the effect of iron supplementation after repeated blood donation on iron status and physiological performance.

MATERIALS AND METHODS

Forty-four moderately trained and iron-replete subjects were randomly divided into a whole blood donation (n=36) and a placebo donation (n=8) group. One third of the donation group received no iron supplementation, whereas one third received 20 mg iron and one third received 80 mg iron daily for 28 days. The subjects were intended to make three donations 3 months apart, and recovery of endurance capacity, assessed by an incremental maximal cycling test, and haematological parameters was monitored up to 28 days after each donation.

RESULTS

Negative effects of repeated blood donation were found for markers of iron storage, markers of functional iron and/or iron metabolism regulation, and physiological markers. Iron supplementation did not affect iron storage but did limit, at the highest dose of 80 mg, the effect of blood donations on functional iron and/or iron metabolism regulation, and at both 20 and 80 mg the negative effects on maximal power output and peak oxygen consumption.

DISCUSSION

Iron supplementation limited the deleterious effects of repeated blood donation on endurance sport performance but not on decline in iron status in iron-replete young men. These results underline the importance of iron supplementation to minimise the deleterious effects of blood donation on physiological functions, and the necessity to optimise the supplementation strategy to preserve iron status.

The acute effects of whole blood donation on cardiorespiratory and haematological factors in exercise: A systematic review

BACKGROUND

This systematic review aimed to collect the relevant historical and current literature to produce an informed analysis of the acute effects on cardiorespiratory and haematological factors following whole blood donation (~ 470 ml) during exercise. Testing the hypothesises that blood donation produces either no changes (Null) or produces significant changes (alternate) in haematology, [Formula: see text], heart rate, exercising power and time.

METHODS

Four databases of medical and science orientations were searched with terms sensitive to connections regarding exercise, blood donation (400-500 ml)/haematology, [Formula: see text], heart rate, exercising power and time. The study retrieval process utilised the PRISMA approach and selection was via an adapted scoring method according to the Consensus based Standards for the selection of health Measurements Instruments (COSMIN). Systematic review focused on 24-48 hrs post donation. Details of the PRSIMA checklist can be found in the accompanying online document.

RESULTS

Following scrutiny of 48 research papers by two independent assessors 8 experimental studies were included. Four studies showed a mean reduction for difference in [Formula: see text] (- 2.4 ± 1.4 ml∙kg-1∙min-1) and a medium effect size (-0.26). No statistical significance was present at the mean meta-analysis level, also the case for heart rate, time to exhaustion and power. A mean reduction was seen in haemoglobin (- 1.05 g.dL-1), haematocrit (- 3.71%) and red blood cells (- 0.44 Mio μL-1), very large effect size was observed (Cohen's d, -0.75, -1.16 and -4.23 respectively) and statistical significance (95% CI, -2.04, -0.54; -4.59, 2.28 and -4.37, -4.10 respectively).

CONCLUSION

Although individual studies show that [Formula: see text] Is reduced from blood donation pooled results show that [Formula: see text] is indeed not significantly reduced from blood donation 24-48 hrs post donation. Additionally sub-maximally there isn't enough data to produce substantial comparatives. Furthermore, this systematic review demonstrates that there are not enough high-quality studies regarding cardiorespiratory outcomes following blood donation.