Red blood cells in sports: effects of exercise and training on oxygen supply by red blood cells

Plasma Concentration of Irisin and Brain-Derived-Neurotrophic Factor and Their Association With the Level of Erythrocyte Adenine Nucleotides in Response to Long-Term Endurance Training at Rest and After a Single Bout of Exercise

The study aimed to assess the effect of a single bout of incremental exercise on irisin and BDNF plasma concentrations as related to erythrocyte purine nucleotides concentration at rest and after exercise. Master endurance master athletes (training experience 38 ± 6 years) and a group of untrained participants completed a single bout of progressive incremental exercise test until exhaustion. The dual-energy x-ray absorptiometry and blood collection were performed. Blood was taken twice at rest and 10 min after exercise. Concentrations of ATP, ADP, and AMP were assessed in the erythrocytes. Hypoxanthine and uric acid were determined in plasma using the high-performance liquid chromatography. Plasma concentrations of irisin and BDNF were assessed through the immunoenzymatic method. The ATP level, ATP/ADP ratio and AEC value were significantly higher in the athletic group. A significantly higher concentration of BDNF was it also noted in the trained group that correlated with the erythrocyte energy status at rest. The single session of exercise induced a significant increase in ATP erythrocyte levels in both groups. Both exerkines significantly correlated at rest with red blood cell adenine nucleotides and degradation products (BDNF positively and irisin negatively). The blood concentration of BDNF and irisin, in response to exercise, was not significantly different between groups. Obtained data revealed a higher erythrocyte energy status and lower purine degradation products concentration in master athletes. Also resting plasma exerkines differed substantially between groups. In conclusion, long-term training resulted in exercise adaptation reflected by a higher erythrocyte energy status, lower purine degradation products concentration and modified concentration of exerkines (higher BDNF and lower irisin blood concentrations). Therefore, we consider the training-induced adaptations in master athletes to be beneficial and significant. The moderate level of physical activity in the untrained group, even if sufficient in terms of general health, did not cause any discernible changes.

Residential Altitude Associates With Endurance but Not Muscle Power in Young Swiss Men

Introduction

Physical fitness benefits health. However, there is a research gap on how physical fitness, particularly aerobic endurance capacity and muscle power, is influenced by residential altitude, blood parameters, weight, and other cofactors in a population living at low to moderate altitudes (300–2100 masl).

Materials and Methods

We explored how endurance and muscle power performance changes with residential altitude, Body Mass Index (BMI), hemoglobin and creatinine levels among 108,677 Swiss men aged 18–22 years (covering >90% of Swiss birth cohorts) conscripted to the Swiss Armed Forces between 2007 and 2012. The test battery included a blood test of about 65%, a physical evaluation of about 85%, and the BMI of all conscripts.

Results

Residential altitude was significantly associated with endurance (p < 0.001) but not with muscle power performance (p = 0.858) after adjusting for all available cofactors. Higher BMI showed the greatest negative association with both endurance and muscle power performance. For muscle power performance, the association with creatinine levels was significant. Elevated C-reactive protein (CRP) and hemoglobin levels were stronger contributors in explaining endurance than muscle power performance.

Conclusion

We found a significant association between low to moderate residential altitude and aerobic endurance capacity even after adjustment for hemoglobin, creatinine, BMI and sociodemographic factors. Non-assessed factors such as vitamin D levels, air pollution, and lifestyle aspects may explain the presented remaining association partially and could also be associated with residential altitude. Monitoring the health and fitness of young people and their determinants is important and of practical concern for disease prevention and public health implications.

Changes in volumetric and metabolic parameters relate to differences in exposure to sub-concussive head impacts

Structural and calibrated magnetic resonance imaging data were acquired on 44 collegiate football players prior to the season (PRE), following the first four weeks in-season (PTC) and one month after the last game (POST). Exposure data collected from g-Force accelerometers mounted to the helmet of each player were used to split participants into HIGH (N = 22) and LOW (N = 22) exposure groups, based on the frequency of impacts sustained by each athlete. Significant decreases in grey-matter volume specific to the HIGH group were documented at POST (P = 0.009), compared to baseline. Changes in resting cerebral blood flow (CBF0), corrected for partial volume effects, were observed within the HIGH group, throughout the season (P < 0.0001), suggesting that alterations in perfusion may follow exposure to sub-concussive collisions. Co-localized significant increases in cerebral metabolic rate of oxygen consumption (CMRO2|0) mid-season were also documented in the HIGH group, with respect to both PRE- and POST values. No physiological changes were observed in the LOW group. Therefore, cerebral metabolic demand may be elevated in players with greater exposure to head impacts. These results provide novel insight into the effects of sub-concussive collisions on brain structure and cerebrovascular physiology and emphasize the importance of multi-modal imaging for a complete characterization of cerebral health.

Iron and Physical Activity: Bioavailability Enhancers, Properties of Black Pepper (Bioperine®) and Potential Applications

Black pepper (Piper nigrum L.) has been employed in medicine (epilepsy, headaches, and diabetes), where its effects are mainly attributed to a nitrogen alkaloid called piperidine (1-(1-[1,3-benzodioxol-5-yl]-1-oxo-2,4 pentenyl) piperidine). Piperine co-administered with vitamins and minerals has improved its absorption. Therefore, this study aimed to describe the impact of the joint administration of iron (Fe) plus black pepper in physically active healthy individuals. Fe is a micronutrient that aids athletic performance by influencing the physiological functions involved in endurance sports by improving the transport, storage, and utilization of oxygen. Consequently, athletes have risk factors for Fe depletion, Fe deficiency, and eventually, anemia, mainly from mechanical hemolysis, gastrointestinal disturbances, and loss of Fe through excessive sweating. Declines in Fe stores have been reported to negatively alter physical capacities such as aerobic capacity, strength, and skeletal muscle recovery in elite athletes. Thus, there is a need to maintain Fe storage, even if Fe intake meets the recommended daily allowance (RDA), and Fe supplementation may be justified in physically active individuals, in states of Fe deficiency, with or without anemia. Females, in particular, should monitor their Fe hematological profile. The recommended oral Fe supplements are ferrous or ferric salts, sulfate, fumarate, and gluconate. These preparations constitute the first line of treatment; however, the high doses administered have gastrointestinal side effects that reduce tolerance and adherence to treatment. Thus, a strategy to counteract these adverse effects is to improve the bioavailability of Fe. Therefore, piperine may benefit the absorption of Fe through its bioavailability enhancement properties. Three research studies of Fe associated with black pepper have reported improvements in parameters related to the metabolism of Fe, without adverse effects. Although more research is needed, this could represent an advance in oral Fe supplementation for physically active individuals.

Repetitive Bouts of Exhaustive Exercise Induces a Systemic Inflammatory Response and Multi-Organ Damage in Rats

Multiple organ dysfunction syndrome can follow severe infection or injury, but its relationship to exercise is not well understood. Previous studies have observed that prolonged strenuous exercise can lead to transiently increased level and/or activity of markers for systemic inflammatory response and multiple organ damage. However, few studies have analyzed the pathogenesis of the inflammatory response and subsequent multi-organ injury in exhaustive exercise conditions. In this study, we established a rat model of repetitive bouts of exhaustive running (RBER) and investigated its effects on multiple organ damage. Rats were subjected to RBER in either uphill or downhill running modes daily for a period of 7 days. Morphologically, RBER causes tissue structural destruction and infiltration of inflammatory cells in the skeletal muscles and many visceral organs. RBER also causes sustained quantitative changes in leukocytes, erythrocytes, and platelets, and changes in the concentration of blood inflammatory factors. These inflammatory alterations are accompanied by increases in serum enzyme levels/activities which serve as functional markers of organ damage. In general, RBER in the downhill mode seemed to cause more damage evaluated by the above-mentioned measures than that produced in the uphill mode. A period of rest could recover some degree of damage, especially for organs such as the heart and kidneys with strong compensatory capacities. Together, our data suggest that, as a result of multi-organ interactions, RBER could cause a sustained inflammatory response for at least 24 h, resulting in tissue lesion and ultimately multiple organ dysfunction.

Spermidine supplementation and voluntary activity differentially affect obesity-related structural changes in the mouse lung

Obesity is associated with lung function impairment and respiratory diseases; however, the underlying pathophysiological mechanisms are still elusive, and therapeutic options are limited. This study examined the effects of prolonged excess fat intake on lung mechanics and microstructure and tested spermidine supplementation and physical activity as intervention strategies. C57BL/6N mice fed control diet (10% fat) or high-fat diet (HFD; 60% fat) were left untreated or were supplemented with 3 mM spermidine, had access to running wheels for voluntary activity, or a combination of both. After 30 wk, lung mechanics was assessed, and left lungs were analyzed by design-based stereology. HFD exerted minor effects on lung mechanics and resulted in higher body weight and elevated lung, air, and septal volumes. The number of alveoli was higher in HFD-fed animals. This was accompanied by an increase in epithelial, but not endothelial, surface area. Moreover, air-blood barrier and endothelium were significantly thicker. Neither treatment affected HFD-related body weights. Spermidine lowered lung volumes as well as endothelial and air-blood barrier thicknesses toward control levels and substantially increased the endothelial surface area under HFD. Activity resulted in decreased volumes of lung, septa, and septal compartments but did not affect vascular changes in HFD-fed mice. The combination treatment showed no additive effect. In conclusion, excess fat consumption induced alveolar capillary remodeling indicative of impaired perfusion and gas diffusion. Spermidine alleviated obesity-related endothelial alterations, indicating a beneficial effect, whereas physical activity reduced lung volumes apparently by other, possibly systemic effects.

Effect of HFE Gene Mutation on Changes in Iron Metabolism Induced by Nordic Walking in Elderly Women

Background

Excess iron accumulation in human tissue is associated with the diet, lack of exercise, or genetic factors. Iron accumulation increases the risk of acute myocardial infarction, diabetes, and cancer. On the other hand, exercise reduces the risk of several morbidities and influences iron metabolism. Here, we evaluated changes in iron metabolism induced by exercise in elderly women bearing the H63A HFE mutation.

Purpose

To identify a factor that modulates the effect of exercise on iron metabolism. We investigated whether regular exercise induces similar changes in iron metabolism, mainly manifested by lowered body iron stores, in individuals bearing the wild-type (WT) and mutated HFE gene.

Subjects and Methods

Seventy-six women (average age 69.2±5.6 years old) were enrolled in the study. Thirty-nine women participated in 12 weeks of Nordic walking (NW) training; the remaining participants were assigned to the control group. Based on the H63A HFE mutation status, the NW group was divided into women bearing the mutation (HET, n=12) and women with the WT gene (WT, n=27).

Results

The training resulted in a statistically significant reduction in the serum iron (p=0.03) and ferritin levels (p=0.001); hepcidin levels remained unchanged. No differences in these parameters were noted between the HET and WT groups.

Conclusion

These observations suggest that a reduction in body iron stores might constitute an important aspect of the health-promoting effect of exercise, regardless of the genetic background.

Metabolomics of Endurance Capacity in World Tour Professional Cyclists

The study of elite athletes provides a unique opportunity to define the upper limits of human physiology and performance. Across a variety of sports, these individuals have trained to optimize the physiological parameters of their bodies in order to compete on the world stage. To characterize endurance capacity, techniques such as heart rate monitoring, indirect calorimetry, and whole blood lactate measurement have provided insight into oxygen utilization, and substrate utilization and preference, as well as total metabolic capacity. However, while these techniques enable the measurement of individual, representative variables critical for sports performance, they lack the molecular resolution that is needed to understand which metabolic adaptations are necessary to influence these metrics. Recent advancements in mass spectrometry-based analytical approaches have enabled the measurement of hundreds to thousands of metabolites in a single analysis. Here we employed targeted and untargeted metabolomics approaches to investigate whole blood responses to exercise in elite World Tour (including Tour de France) professional cyclists before and after a graded maximal physiological test. As cyclists within this group demonstrated varying blood lactate accumulation as a function of power output, which is an indicator of performance, we compared metabolic profiles with respect to lactate production to identify adaptations associated with physiological performance. We report that numerous metabolic adaptations occur within this physically elite population (n = 21 males, 28.2 ± 4.7 years old) in association with the rate of lactate accumulation during cycling. Correlation of metabolite values with lactate accumulation has revealed metabolic adaptations that occur in conjunction with improved endurance capacity. In this population, cycling induced increases in tricarboxylic acid (TCA) cycle metabolites and Coenzyme A precursors. These responses occurred proportionally to lactate accumulation, suggesting a link between enhanced mitochondrial networks and the ability to sustain higher workloads. In association with lactate accumulation, altered levels of amino acids before and after exercise point to adaptations that confer unique substrate preference for energy production or to promote more rapid recovery. Cyclists with slower lactate accumulation also have higher levels of basal oxidative stress markers, suggesting long term physiological adaptations in these individuals that support their premier competitive status in worldwide competitions.

High-intensity interval training irrespective of its intensity improves markers of blood fluidity in hypertensive patients

Aim: The present study examined and compared the effects of two different HIIT (High-intensity interval training) protocols on markers of blood fluidity in hypertensive patients.Methods: Thirty hypertensive (stage 1, systolic BP >140 and diastolic BP>90 mmHg) patients (age, 47.96 ± 3.20 yrs), were randomly allocated to short-duration HIIT (SDHIIT, n = 10), long-duration HIIT (LDHIIT, n = 10), and control (n = 10) groups. After 2 weeks of continuous mild training, patients in SDHIIT group performed 8 weeks of HIIT included 27 min HIIT that encompassed 27 repetitions of 30 s activity at 80%-100% of VO₂peak interspersed by 30 s passive/active (10%-20% of VO₂peak) recovery, while, patients in LDHIIT group performed 8 weeks of HIIT (32 min per session) included 4 repetitions of 4 min activity at 75%-90% of VO₂peak interspersed by 4 min passive/active (15%-30% of VO₂peak) recovery. Two blood samples were taken before and after training and were analyzed for hemorheological variables.Results: Significant (P < .05) reductions in systolic blood pressure (SBP), blood and plasma viscosity, fibrinogen concentration and red blood cell (RBC) aggregation (8-12%) were found following two training protocols (P < .05), though, the differences between adaptations were not statistically significant (P > .05). In addition, HIIT protocols increased RBC deformability significantly (P < .05), with no significant differences being observed between two protocols.Conclusion: It is concluded that HIIT training reduces SBP and markers of blood fluidity in patients with stage 1 hypertension irrespective of the HIIT intensity and duration. Therefore, this type of exercise training could be prescribed for improving the blood fluidity markers in hypertensive patients.

Effect of Resistance Training Under Normobaric Hypoxia on Physical Performance, Hematological Parameters, and Body Composition in Young and Older People

Background

Resistance training (RT) under hypoxic conditions has been used to increase muscular performance under normoxic conditions in young people. However, the effects of RT and thus of RT under hypoxia (RTH) could also be valuable for parameters of physical capacity and body composition across the lifespan. Therefore, we compared the effects of low- to moderate-load RTH with matched designed RT on muscular strength capacity, cardiopulmonary capacity, hematological adaptation, and body composition in young and older people.

Methods

In a pre–post randomized, blinded, and controlled experiment, 42 young (18 to 30 year) and 42 older (60 to 75 year) participants were randomly assigned to RTH or RT (RTH young, RT young, RTH old, RT old). Both groups performed eight resistance exercises (25–40% of 1RM, 3 × 15 repetitions) four times a week over 5 weeks. The intensity of hypoxic air for the RTH was administered individually in regards to the oxygen saturation of the blood (SpO₂): ∼80–85%. Changes and differences in maximal isokinetic strength, cardiopulmonary capacity, total hemoglobin mass (tHb), blood volume (BV), fat free mass (FFM), and fat mass (FM) were determined pre–post, and the acute reaction of erythropoietin (EPO) was tested during the intervention.

Results

In all parameters, no significant pre–post differences in mean changes (time × group effects p = 0.120 to 1.000) were found between RTH and RT within the age groups. However, within the four groups, isolated significant improvements (p < 0.050) of the single groups were observed regarding the muscular strength of the legs and the cardiopulmonary capacity.

Discussion

Although the hypoxic dose and the exercise variables of the resistance training in this study were based on the current recommendations of RTH, the RTH design used had no superior effect on the tested parameters in young and older people in comparison to the matched designed RT under normoxia after a 5-week intervention period. Based on previous RTH-studies as well as the knowledge about RT in general, it can be assumed that the expected higher effects of RTH can may be achieved by changing exercise variables (e.g., longer intervention period, higher loads).

The Effect of One Bout of Intensive Judo Exercise on Select Hematological and Immunological Parameters in Adolescent Elite Judo Athletes

Background: Exercise-related studies do not agree on changes in blood parameters regarding anemia and serum immunoglobulin concentration as adaptive immunity. Objectives: The current study aimed to investigate exercise-induced variations in hematological and immunological parameters in response to one bout of intensive judo exercise in adolescent elite judoka. Methods: Venipuncture was performed on ten adolescent male Iranian elite judoka (age: 15.60 ± 0.69 years; body mass index: 24.15 ± 2.80 kg/m2) before and immediately after one bout of intensive judo protocol. Erythrocyte variables [red blood cell count (RBC), hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), red distribution width (RDW), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC)], platelets variables [platelet count (PLT), platelet distribution width (PDW), mean platelet volume (MPV), plateletcrit (PCT)], cellular immune variables [white blood cell (WBC), neutrophil (NEU), lymphocyte (LYM)], and humoral immune variables (IgM, IgA, IgG, IgE) were measured. Data were analyzed using Wilcoxon and paired-samples t-test, and P < 0.05 was considered significant. Results: After the plasma volume was corrected using the Dill and Costill equation, the results showed that RBC, HGB, HCT, MCHC, IgA, and IgM decreased significantly immediately after exercise. However, MCH, RDW, PLT, PDW, MPV, PCT, WBC, LYM, NEU, IgG, and IgE did not change significantly. Conclusions: According to the findings, it can be concluded that intensive judo exercise results in transient anemia and suppression of humoral immune response among adolescent elite judoka.

Anserine Reverses Exercise-Induced Oxidative Stress and Preserves Cellular Homeostasis in Healthy Men

The study tested whether anserine (beta-alanyl-3-methyl-l-histidine), the active ingredient of chicken essence affects exercise-induced oxidative stress, cell integrity, and haematology biomarkers. In a randomized placebo-controlled repeated-measures design, ten healthy men ingested anserine in either a low dose (ANS-LD) 15 mg·kg⁻¹·bw⁻¹, high dose (ANS-HD) 30 mg·kg⁻¹·bw⁻¹, or placebo (PLA), following an exercise challenge (time to exhaustion), on three separate occasions. Anserine supplementation increased superoxide dismutase (SOD) by 50% (p < 0.001, effect size d = 0.8 for both ANS-LD and ANS-HD), and preserved catalase (CAT) activity suggesting an improved antioxidant activity. However, both ANS-LD and ANS-HD elevated glutathione disulfide (GSSG), (both p < 0.001, main treatment effect), and consequently lowered the glutathione to glutathione disulfide (GSH/GSSG) ratio compared with PLA (p < 0.01, main treatment effect), without significant effects on thiobarbituric acid active reactive substances (TBARS). Exercise-induced cell damage biomarkers of glutamic-oxaloacetic transaminase (GOT) and myoglobin were unaffected by anserine. There were slight but significant elevations in glutamate pyruvate transaminase (GPT) and creatine kinase isoenzyme (CKMB), especially in ANS-HD (p < 0.05) compared with ANS-LD or PLA. Haematological biomarkers were largely unaffected by anserine, its dose, and without interaction with post exercise time-course. However, compared with ANS-LD and PLA, ANS-HD increased the mean cell volume (MCV), and decreased the mean corpuscular haemoglobin concentration (MCHC) (p < 0.001). Anserine preserves cellular homoeostasis through enhanced antioxidant activity and protects cell integrity in healthy men, which is important for chronic disease prevention. However, anserine temporal elevated exercise-induced cell-damage, together with enhanced antioxidant activity and haematological responses suggest an augmented exercise-induced adaptative response and recovery.

Heart of the World's Top Ultramarathon Runner-Not Necessarily Much Different from Normal

The impact of ultramarathon (UM) runs on the organs of competitors, especially elite individuals, is poorly understood. We tested a 36-year-old UM runner before, 1–2 days after, and 10–11 days after winning a 24-h UM as a part of the Polish Championships (258.228 km). During each testing session, we performed an electrocardiogram (ECG), transthoracic echocardiography (TTE), cardiac magnetic resonance imaging (MRI), cardiac ³¹P magnetic resonance spectroscopy (³¹P MRS), and blood tests. Initially, increased cholesterol and low-density lipoprotein cholesterol (LDL-C) levels were identified. The day after the UM, increased levels of white blood cells, neutrophils, fibrinogen, alanine aminotransferase, aspartate aminotransferase, creatine kinase, C-reactive protein, and N-terminal type B natriuretic propeptide were observed. Additionally, decreases in hemoglobin, hematocrit, cholesterol, LDL-C, and hyponatremia were observed. On day 10, all measurements returned to normal levels, and cholesterol and LDL-C returned to their baseline abnormal values. ECG, TTE, MRI, and ³¹P MRS remained within the normal ranges, demonstrating physiological adaptation to exercise. The transient changes in laboratory test results were typical for the extreme efforts of the athlete and most likely reflected transient but massive striated muscle damage, liver cell damage, activation of inflammatory processes, effects on the coagulation system, exercise-associated hyponatremia, and cytoprotective or growth-regulatory effects. These results indicated that many years of intensive endurance training and numerous UMs (including the last 24-h UM) did not have a permanent adverse effect on this world-class UM runner’s body and heart. Transient post-competition anomalies in laboratory test results were typical of those commonly observed after UM efforts.

Alterations in the innate immune system due to exhausting exercise in intensively trained rats

It is known that intensive physical activity alters the immune system's functionality. However, the influence of the intensity and duration of exercise needs to be studied in more depth. We aimed to establish the changes in the innate immune response induced by two programmes of intensive training in rats compared to sedentary rats. A short training programme included 2 weeks of intensive training, ending with an exhaustion test (short training with exhaustion, S-TE). A second training programme comprised 5-week training including two exhaustion tests and three trainings per week. In this case, immune status was assessed before (T), immediately after (TE) and 24 h after (TE24) an additional final exhaustion test. Biomarkers such as phagocytic activity, macrophage cytokine and reactive oxygen species (ROS) production, and natural killer (NK) cell activity were quantified. S-TE was not enough to induce changes in the assessed innate immunity biomarkers. However, the second training was accompanied by a decrease in the phagocytic activity, changes in the pattern of cytokine secretion and ROS production by macrophages and reduced NK cell proportion but increased NK cytotoxic activity. In conclusion, a 5-week intense training programme, but not a shorter training, induced alterations in the innate immune system functionality.

Vitamins and Minerals for Energy, Fatigue and Cognition: A Narrative Review of the Biochemical and Clinical Evidence

Vitamins and minerals are essential to humans as they play essential roles in a variety of basic metabolic pathways that support fundamental cellular functions. In particular, their involvement in energy-yielding metabolism, DNA synthesis, oxygen transport, and neuronal functions makes them critical for brain and muscular function. These, in turn, translate into effects on cognitive and psychological processes, including mental and physical fatigue. This review is focused on B vitamins (B1, B2, B3, B5, B6, B8, B9 and B12), vitamin C, iron, magnesium and zinc, which have recognized roles in these outcomes. It summarizes the biochemical bases and actions of these micronutrients at both the molecular and cellular levels and connects them with cognitive and psychological symptoms, as well as manifestations of fatigue that may occur when status or supplies of these micronutrients are not adequate.

The Influence of a Health-Related Fitness Training Program on Motor Performance as Well as Hematological and Biochemical Parameters

The study was aimed at designing a health exercise program appealing to inactive young men, and then testing the men's metabolic responses to the program using common diagnostic markers of general health. Six men, aged 22-29 years, took a part in training program to increase their motor performance and improve general health conditions. Body composition parameters, clinical chemistry variables (metabolites, albumin, total protein, ferritin, C reactive protein, lipid profile, ions, and selected enzymes activities) and blood morphology parameters were determined. Motor performance measured before and after a 4-month-long macrocycle indicated an increase in endurance, pace, and agility of the participants. Significant differences were found in analyzed enzymes activities. There was a significant increase in C-reactive protein levels from pre- to post-training. Additionally, changes in hematological biomarkers were seen that suggest erythropoiesis might significantly increase, specifically during the last 2-month-long mesocycles. The proposed training program induced small improvements in endurance, pace, and agility. It was also confirmed that changes in aspartate (AST) and alanine (ALT) activities emerge before any increase in creatine kinase (CK) activity that is important in monitoring of the training loads. Observed changes in red blood cell-related parameters suggest increase in erythropoiesis in the second half of the training cycle.

Quantification of the Mean and Distribution of Hemoglobin Content in Normal Human Blood Using Cell Tracking Velocimetry

The current clinical method for detecting anemia focuses on measuring the concentration of hemoglobin (Hb) in blood. However, recent developments in particle tracking algorithms and the understanding of the relationship between Hb and magnetism has enabled the quantitative measurement of the Hb content in a single red blood cell, RBC, based on magnetophoretic mobility. To further explore this relationship, 22 human blood samples obtained from 17 healthy volunteers were analyzed by the cell tracking velocimetry system, and the calculated Hb concentration from these measurements was compared to the values measured by UV-visible spectrophotometry, the standard method for measuring Hb in clinical laboratories. The results show close correlations between the mean of the spectrophotometric and magnetophoretic methods; however, single cell analysis with the magnetophoretic mobility method allows further elucidation of the distribution of Hb concentration within RBCs from a donor sample to be determined. Histograms of these magnetophoretic mobility distributions indicate that the fraction of RBCs that are below the bulk Hb concentration that defines anemia varies not only from donor to donor but also in the same donor over time. Consistent with a variable fraction below the anemic Hb concentration, the distribution around the mean has a large range. Previous studies have indicated that RBCs lose Hb during ex vivo storage; however, it is not known if this variability in the distribution of Hb content is a function of the age of the RBCs in a donor, suggesting a variable rate in RBC production between donors, or variability in available iron at the time of RBC formation. We suggest our cell tracking velocimetry system can reveal more information regarding this matter.

Acute Low-Dose Hyperoxia during a Single Bout of High-Intensity Interval Exercise Does Not Affect Red Blood Cell Deformability and Muscle Oxygenation in Trained Men-A Randomized Crossover Study

Recent technological developments provide easy access to use an artificial oxygen supply (hyperoxia) during exercise training. The aim of this study was to assess the efficacy of a commercially available oxygen compressor inducing low-dose hyperoxia, on limiting factors of endurance performance. Thirteen active men (age 24 ± 3 years) performed a high-intensity interval exercise (HIIE) session (5 × 3 min at 80% of W_max, separated by 2 min at 40% W_max) on a cycle ergometer, both in hyperoxia (4 L∙min⁻¹, 94% O₂, HYP) or ambient conditions (21% O₂, NORM) in randomized order. The primary outcome was defined as red blood cell deformability (RBC-D), while our secondary interest included changes in muscle oxygenation. RBC-D was expressed by the ratio of shear stress at half-maximal deformation (SS¹/₂) and maximal deformability (EI_max) and muscle oxygenation of the rectus femoris muscle was assessed by near-infrared spectroscopy. No statistically significant changes occurred in SS¹/₂ and EI_max in either condition. The ratio of SS¹/₂ to EI_max statistically decreased in NORM (p < 0.01; Δ: −0.10; 95%CI: −0.22, 0.02) but not HYP (p > 0.05; Δ: −0.16; 95%CI: −0.23, −0.08). Muscle oxygenation remained unchanged. This study showed that low-dose hyperoxia during HIIE using a commercially available device with a flow rate of only 4 L·min⁻¹ may not be sufficient to induce acute ergogenic effects compared to normoxic conditions.

Obesity-Induced Changes in Bone Marrow Homeostasis

Obesity is characterized by low-grade inflammation, which is accompanied by increased accumulation of immune cells in peripheral tissues including adipose tissue (AT), skeletal muscle, liver and pancreas, thereby impairing their primary metabolic functions in the regulation of glucose homeostasis. Obesity has also shown to have a detrimental effect on bone homeostasis by altering bone marrow and hematopoietic stem cell differentiation and thus impairing bone integrity and immune cell properties. The origin of immune cells arises in the bone marrow, which has been shown to be affected with the obesogenic condition via increased cellularity and shifting differentiation and function of hematopoietic and bone marrow mesenchymal stem cells in favor of myeloid progenitors and increased bone marrow adiposity. These obesity-induced changes in the bone marrow microenvironment lead to dramatic bone marrow remodeling and compromising immune cell functions, which in turn affect systemic inflammatory conditions and regulation of whole-body metabolism. However, there is limited information on the inflammatory secretory factors creating the bone marrow microenvironment and how these factors changed during metabolic complications. This review summarizes recent findings on inflammatory and cellular changes in the bone marrow in relation to obesity and further discuss whether dietary intervention or physical activity may have beneficial effects on the bone marrow microenvironment and whole-body metabolism.

Serum Autofluorescence and Biochemical Markers in Athlete's Response to Strength Effort in Normobaric Hypoxia: A Preliminary Study

The human organism has the ability to adapt to hypoxia conditions. Training in hypoxia is used in sport to improve the efficiency of athletes; however, type of training affects the direction and scope of this process. Therefore, in this study, the usefulness of serum fluorescence spectroscopy to study the assessment of athlete's response to strength effort in hypoxia is considered in comparison with biochemical assay. Six resistance-trained male subjects took part in a research experiment. They performed barbell squats in simulated normobaric hypoxic conditions with deficiency of oxygen 11.3%, 13% 14.3% compared to 21% in normoxic conditions. Fluorescence intensity of tyrosine revealed high sensitivity on strength effort whereas tryptophan was more dependent on high altitude. Changes in emission in the visible region are associated with altering cell metabolism dependent on high altitude as well as strength training and endurance training. Significant changes in serum fluorescence intensity with relatively weak modifications in biochemical assay at 3000 m above sea level (ASL) were observed. Training at 5000 m ASL caused changes in fluorescence parameters towards the normobaric specific values, and pronounced decreases of lactate level and kinase creatine activity were observed. Such modifications of fluorescence and biochemical assay indicate increased adaptation of the organism to effort in oxygen-deficient conditions at 5000 m ASL, unlike 3000 m ASL. Fluorescence spectroscopy study of serum accompanied by biochemical assay can contribute to the understanding of metabolic regulation and the physiological response to hypoxia. The results of serum autofluorescence during various concepts of altitude training may be a useful method to analyze individual response to acute and chronic hypoxia. An endogenous tryptophan could be exploited as intrinsic biomarker in autofluorescence studies. However, these issues require further research.

The Effect of Training on Erythrocyte Energy Status and Plasma Purine Metabolites in Athletes

This study aimed to assess the changes in red blood cell (RBC) energy status and plasma purine metabolites concentration over a one-year training cycle in endurance-trained (EN; n = 11, 20–26 years), and sprint-trained (SP; n = 11, 20–30 years) competitive athletes in comparison to recreationally-trained individuals (RE; n = 11, 20–26 years). Somatic, physiological, and biochemical variables were measured in four training phases differing in exercise load profile: transition, general, specific, and competition. Significantly highest values of RBC adenylate energy charge (AEC; p ≤ 0.001), ATP-to-ADP and ADP-to-AMP ratios (p ≤ 0.05), and plasma levels of adenosine (Ado; p ≤ 0.05) were noted in the competition phase in the EN and SP, but not in the RE group. Significantly lowest plasma levels of adenosine diphosphate (ADP; p ≤ 0.05), adenosine monophosphate (AMP; p ≤ 0.001), inosine (Ino; p ≤ 0.001), and hypoxanthine (Hx; p ≤ 0.001) accompanied by higher erythrocyte hypoxanthine-guanine phosphoribosyltransferase (HGPRT) activity (p ≤ 0.001), were observed in the competition phase in both athletic groups. No significant alterations were found in the erythrocyte concentration of guanine nucleotides in any group. In conclusion, periodized training of competitive athletes’ results in a favorable adaptation of RBC metabolism. The observed changes cover improved RBC energy status (increased AEC and ATP/ADP ratio) and reduced purine loss with more efficient erythrocyte purine pool recovery (increased HGPRT activity and plasma levels of Ado; decreased Hx and Ino concentration).

Twelve Weeks of Combined Resistance and Aerobic Exercise Improves Cardiometabolic Biomarkers and Enhances Red Blood Cell Hemorheological Function in Obese Older Men: A Randomized Controlled Trial

The present study examined the effect of a 12-week combined resistance and aerobic exercise training program on cardiometabolic biomarkers and red blood cell (RBC) hemorheological function in 20 obese older men (mean age: 68.8 ± 0.9 years). Subjects were randomly divided into two groups (exercise intervention [EXP; n = 10] and control [CON; n = 10]). The EXP subjects performed resistance and aerobic exercise training program three times per week for 12 weeks, and the CON subjects maintained their regular lifestyle during the intervention period. Body composition was estimated using bioelectrical impedance analysis equipment. Cardiometabolic biomarkers (glucose, insulin, homeostasis model assessment-estimated insulin resistance (HOMA-IR), HOMA β-cell function, and leptin) and RBC hemorheological parameters (RBC deformability and aggregation) were analyzed. Percent body fat decreased significantly in the EXP group during the intervention period but increased significantly in the CON group. Insulin increased significantly in the CON group over the 12-week period and both insulin and HOMA-IR were significantly higher in the CON group than in the EXP group at post-test. RBC deformability (RBC EI_3Pa) and aggregation (RBC AI_3Pa) improved significantly only in the EXP group. The present study suggests that combined exercise training can be useful for improving cardiometabolic biomarkers and RBC hemorheological parameters in obese older men and may help prevent metabolic syndrome and cardiovascular diseases.

Hemoglobin During and Following a 4-Week Commercial Saturation Dive to 200 m

Commercial saturation divers must acclimatize to hyperbaric hyperoxia in their work environment, and subsequently readjust to breathing normal air when their period in saturation is over. In this study, we measured hemoglobin (Hb) during and following 4 weeks of heliox saturation diving in order to monitor anemia development and the time for Hb to recover post-saturation. Male commercial saturation divers reported their capillary blood Hb daily, before, and during 28 days of heliox saturation to a working depth of circa 200 m (n = 11), and for 12 days at surface post-saturation (n = 9–7), using HemoCue 201+ Hb devices. Hb remained in normal range during the bottom phase, but fell during the decompression; reaching levels of mild anemia (≤13.6 g/dl) the day after the divers’ return to the surface. Hb was significantly lower than the pre-saturation baseline (14.7 ± 1.1 g/dl) on the fifth day post-saturation (12.8 ± 1.8 g/dl, p = 0.028), before reverting to normal after 6–7 days. At the end of the 12-day post-saturation period, Hb was not statistically different from the pre-saturation baseline. The observed Hb changes, although significant, were modest. While we cannot rule out effect of other factors, the presence of mild anemia may partially explain the transient fatigue that commercial saturation divers experience post-saturation.

Identification of Potential Performance-Related Predictors in Young Competitive Athletes

Introduction

Systematic training is an essential demand for the individual success of an athlete. However, similar training modalities cause individual responses, and finally, decide on athletes’ success or failure. To predict performance development, potential influencing parameters should be known. Therefore, the purpose of this study was to identify performance-related parameters in young competitive athletes.

Methods

Individual performance developments of 146 young athletes (m: n = 96, f: n = 50, age V1: 14.7 ± 1.7 years) of four different sports (soccer: n = 45, cycling: n = 48, swimming: n = 18, cross-country skiing: n = 35) were evaluated by analysis of 356 visits in total (exercise intervention periods, 289 ± 112 d). At V1 and V2 several performance parameters were determined. Based on the relative performance progress (Δ), potential influencing predictors were analyzed: training load, health sense, stress level, clinical complaints, hemoglobin, vitamin D, hs-CRP and EBV serostatus. Data were collected within a controlled, prospective study on young athletes, which was conducted between 2010 and 2014.

Results

Athletes improved their performance by 4.7 ± 10.7%. In total, 66.3% of all athletes represented a positive performance progress. This group demonstrated, despite similar training loads (p = 0.207), enhanced health senses (p = 0.001) and lower stress levels (p = 0.002). In contrast, compared to athletes with an impaired performance progress, no differences in hemoglobin values (m: p = 0.926, f: p = 0.578), vitamin D levels (0.787) and EBV serostatus (p = 0.842) were found. Performance progress was dependent on extents of health senses (p = 0.040) and stress levels (p = 0.045). Furthermore, the combination of declined health senses and rised stress levels was associated with an impaired performance development (p = 0.018) and higher prevalences of clinical complaints (p < 0.001) above all, in contrast to hs-CRP (p = 0.168).

Discussion

Athletes with an improved performance progress reported less pronounced subjective sensations and complaints. In contrast, objective known performance-related indicators, offered no differences. Therefore, subjective self-reported data, reflecting health and stress status, should be additionally considered to regulate training, modify intensities, and finally, predict and ensure an optimal performance advance.

Impact of A Six Week Training Program on Ventilatory Efficiency, Red Blood Cell Rheological Parameters and Red Blood Cell Nitric Oxide Signaling in Young Sickle Cell Anemia Patients: A Pilot Study

Patients with sickle cell anemia (SCA) show impaired ventilatory efficiency, altered blood rheology, high levels of oxidative/nitrosative stress and enhanced hemolysis with large amounts of circulating free hemoglobin, which reduces nitric oxide (NO) bioavailability. The aim of the study was to investigate whether physical exercise could improve these physiological and biological markers described to contribute to SCA pathophysiology. Twelve SCA patients participated in a controlled six weeks training program with moderate volume (two sessions per week with 15–30 min duration per session) and intensity (70% of the first ventilatory threshold). Parameters were compared before (T0) and after (T1) training. Daily activities were examined by a questionnaire at T0 and one year after the end of T1. Results revealed improved ventilatory efficiency, reduced nitrosative stress, reduced plasma free hemoglobin concentration, increased plasma nitrite levels and altered rheology at T1 while no effect was observed for exercise performance parameters or hematological profile. Red blood cell (RBC) NO parameters indicate increased NO bioavailability which did not affect RBC deformability. Participants increased their daily life activity level. The data from this pilot study concludes that even low intensity activities are feasible and could be beneficial for the health of SCA patients.

Hematological, Hormonal and Fitness Indices in Youth Swimmers: Gender-Related Comparisons

This study objective was to evaluate gender differences in hematological, hormonal and fitness variables among youth swimmers and to explore relationships between erythrocyte indices and aerobic and anaerobic capacity. 137 girls and 171 boys participated in the study and were divided into three groups based on their training experience. Blood samples were obtained to determine red blood cell counts, hemoglobin concentration, hematocrit, and plasma erythropoietin and testosterone levels. VO_2max was assessed using a submaximal cycle protocol. 76 girls and 102 boys also undertook a Wingate test to determine their peak anaerobic power. Boys had higher (p < 0.05) means than girls for all hematological variables except for erythropoietin and these variables demonstrated an increase with training in boys. The average VO_2max in l∙min^-1 and peak anaerobic power in watts were also higher in boys (2.91 ± 0.08 and 547 ± 28, respectively) than girls (2.25 ± 0.07 and 450 ± 26, respectively). Modest but significant (p < 0.05) correlations were found between VO_2max and red blood cell counts (r = 0.252), hemoglobin concentration (r = 0.345), or hematocrit (r = 0.345) and between peak anaerobic power and red blood cell counts (r = 0.304), hemoglobin concentration (r = 0.319) or hematocrit (r = 0.351). This study revealed relatively lower yet age- and gender-appropriate hematological, hormonal and fitness indices in youth swimmers. The gender-related differences in erythrocyte indices seem unrelated to erythropoietin and may be explained by the higher testosterone levels seen in boys. Given their correlation to both aerobic and anaerobic capacity, erythrocyte indices may be used as part of talent identification for sports.

Alterations in Exercise-Induced Plasma Adenosine Triphosphate Concentration in Highly Trained Athletes in a One-Year Training Cycle

This study aimed to assess the effect of training loads on plasma adenosine triphosphate responsiveness in highly trained athletes in a 1 y cycle. Highly trained futsal players (11 men, age range 20–31 y), endurance athletes (11 men, age range 18–31 y), sprinters (11 men, age range 21–30 y), and control group (11 men, age range 22–34 y) were examined across four characteristic training phases in response to an incremental treadmill test until exhaustion. A considerably higher exercise and post-exercise plasma adenosine triphosphate concentrations were observed in consecutive training phases in highly trained athletes, with the highest values reached after the competitive period. No differences in plasma adenosine triphosphate concentrations were found in the control group during the 1 y cycle. Sprinters showed a higher absolute and net increase in plasma adenosine triphosphate concentration by 60–114% during exercise in consecutive training phases than futsal players (63–101%) and endurance athletes (64–95%). In this study, we demonstrated that exercise-induced adenosine triphosphate concentration significantly changes in highly trained athletes over an annual training cycle. The obtained results showed that high-intensity but not low- to moderate-intensity training leads to an increased adenosine triphosphate response to exercise, suggesting an important role of ATP for vascular plasticity.

A Study of the Change in Sodium and Potassium Ion Concentrations in Stored Donor Blood and Their Effect on Electrolyte Balance of Recipients

Background

Preserved blood cells undergo progressive structural and functional changes that may affect their function, integrity, and viability after transfusion. The impact of transfusion of stored blood on potassium, sodium, or acid-base balance in the recipient may be complex, but information on it is inconsistent. This study therefore sought to determine the changes in the potassium and sodium levels in whole blood stored at 4°C for 28 days and clinical outcomes when such blood are transfused.

Methods

Whole blood were taken into double CPDA-1 bags and 50 ml transferred into the satellite bags for the study. Electrolyte concentration determinations were made on each of the blood sample on days 0, 7, 14, 21, and 28 using the Vitalab Selectra Junior chemistry analyser. The remaining blood in the main bags was transfused after the 28-day period, and biochemical analysis carried out on the patients before and after the transfusion. One-way ANOVA was used for the analysis of variance between the weekly ion concentrations and independent sample Mann-Whitney U test for the data obtained from the patients.

Results

The mean potassium level of all the samples started with a normal value of 3.45 mmol/L on the first day followed by a sharp rise to 9.40 mmol/L on day 7, 13.40 mmol/L on day 14, 14.60 mmol/L on day 21, and 15.40 mmol/L on day 28. Sodium on the other hand started with a high value of 148.4 mmol/L on day 0 and then reduced to 146.4 mmol/L on day 7, 140.8 mmol/L on day 14, 135.6 mmol/L on day 21, and a low value of 130.8 mmol/L on day 28. No adverse clinical outcomes were seen in patients after they were transfused with the blood.

Conclusion

It can be deduced that potassium concentration in refrigerated blood increases, whilst sodium concentration reduces with time and when such blood is transfused, it may not result in any adverse clinical outcome.

Comparison for immunophysiological responses of Jeju and Thoroughbred horses after exercise

OBJECTIVE

The study was conducted to investigate variations in the immunophysiological responses to exercise-induced stress in Jeju and Thoroughbred horses.

METHODS

Blood samples were collected from the jugular veins of adult Jeju (n = 5) and Thoroughbred (n = 5) horses before and after 30 min of exercise. The hematological, biochemical, and immunological profiles of the blood samples were analyzed. Blood smears were stained and observed under a microscope. The concentration of cell-free (cf) DNA in the plasma was determined using real time polymerase chain reaction (PCR). Peripheral blood mononuclear cells (PBMCs) and polymorphonuclear cells were separated using Polymorphprep, and the expression of various stress-related and chemokine receptor genes was measured using reverse transcriptase (RT) and real-time PCR.

RESULTS

After exercise, Jeju and Thoroughbred horses displayed stress responses with significantly increased rectal temperatures, cortisol levels, and muscle catabolism-associated metabolites. Red blood cell indices were significantly higher in Thoroughbred horses than in Jeju horses after exercise. In addition, exercise-induced stress triggered the formation of neutrophil extracellular traps (NETs) and reduced platelet counts in Jeju horses but not in Thoroughbred horses. Heat shock protein 72 and heat shock protein family A (Hsp70) member 6 expression is rapidly modulated in response to exercise-induced stress in the PBMCs of Jeju horses. The expression of CXC chemokine receptor 4 in PBMCs was higher in Thoroughbred horses than in Jeju horses after exercise.

CONCLUSION

In summary, the different immunophysiological responses of Jeju and Thoroughbred horses explain the differences in the physiological and anatomical properties of the two breeds. The physiology of Thoroughbred horses makes them suitable for racing as they are less sensitive to exercise-induced stress compared to that of Jeju horses. This study provides a basis for investigating the link between exercise-induced stresses and the physiological alteration of horses. Hence, our findings show that some of assessed parameters could be used to determine the endurance performance of horses.

Effect of acute exercise on RBC deformability and RBC nitric oxide synthase signalling pathway in young sickle cell anaemia patients

Sickle cell anaemia (SCA) is characterized by reduced red blood cell (RBC) deformability and nitric oxide (NO) bioavailability. The aim of the study was to investigate whether exercise might affect these parameters in SCA. SCA patients and healthy controls (AA) performed an acute submaximal exercise test until subjects reached the first ventilatory threshold (VT 1). Blood was sampled at rest and at VT 1. At rest, free haemoglobin level was higher and RBC count, haemoglobin and haematocrit were lower in SCA compared to AA. RBC deformability was lower in SCA. Exercise had no effect on the tested parameters. RBC NO level was higher in SCA compared to AA at rest and significantly decreased after exercise in SCA. This might be related to a reduction in RBC-NO synthase (RBC-NOS) activation which was only observed in SCA after exercise. Free radical levels were higher in SCA at rest but concentration was not affected by exercise. Marker for lipid peroxidation and antioxidative capacity were similar in SCA and AA and not affected by exercise. In conclusion, a single acute submaximal bout of exercise has no deleterious effects on RBC deformability or oxidative stress markers in SCA, and seems to modulate RBC-NOS signalling pathway.

Effects of a six-week period of congested match play on plasma volume variations, hematological parameters, training workload and physical fitness in elite soccer players

Objectives

The aims of this study were to investigate the effects of a six-week in-season period of soccer training and games (congested period) on plasma volume variations (PV), hematological parameters, and physical fitness in elite players. In addition, we analyzed relationships between training load, hematological parameters and players’ physical fitness.

Methods

Eighteen elite players were evaluated before (T1) and after (T2) a six-week in-season period interspersed with 10 soccer matches. At T1 and T2, players performed the Yo-Yo intermittent recovery test level 1 (YYIR1), the repeated shuttle sprint ability test (RSSA), the countermovement jump test (CMJ), and the squat jump test (SJ). In addition, PV and hematological parameters (erythrocytes [M/mm³], hematocrit [%], hemoglobin [g/dl], mean corpuscular volume [fl], mean corpuscular hemoglobin content [pg], and mean hemoglobin concentration [%]) were assessed. Daily ratings of perceived exertion (RPE) were monitored in order to quantify the internal training load.

Results

From T1 to T2, significant performance declines were found for the YYIR1 (p<0.001, effect size [ES] = 0.5), RSSA (p<0.01, ES = 0.6) and SJ tests (p< 0.046, ES = 0.7). However, no significant changes were found for the CMJ (p = 0.86, ES = 0.1). Post-exercise, RSSA blood lactate (p<0.012, ES = 0.2) and PV (p<0.01, ES = 0.7) increased significantly from T1 to T2. A significant decrease was found from T1 to T2 for the erythrocyte value (p<0.002, ES = 0.5) and the hemoglobin concentration (p<0.018, ES = 0.8). The hematocrit percentage rate was also significantly lower (p<0.001, ES = 0.6) at T2. The mean corpuscular volume, mean corpuscular hemoglobin content and the mean hemoglobin content values were not statistically different from T1 to T2. No significant relationships were detected between training load parameters and percentage changes of hematological parameters. However, a significant relationship was observed between training load and changes in RSSA performance (r = -0.60; p<0.003).

Conclusions

An intensive period of “congested match play” over 6 weeks significantly compromised players’ physical fitness. These changes were not related to hematological parameters, even though significant alterations were detected for selected measures.

The intranasal AlaxoLito Plus Nasal Stent: Improvement of NO-induced microrheology and oxygen uptake during exercise?

AIM

To investigate the influence of the intranasal AlaxoLito Plus Nasal Stent during exercise on nitric oxide (NO) synthesis, NO exhalation, red blood cell (RBC) deformability and oxygen uptake.

METHODS

Parameters were measured before and after acute cycle ergometer test at different intensities. Spirometric, microrheological and NO parameters were determined for oral (OB), nasal (NB) and nasal-stent breathing (SB). RBC deformability was measured and elongation indices for 3.87 Pa and maximal deformability were calculated. RBC/plasma/exhaled NO, oxygen uptake and respiratory rate were determined.

RESULTS

Exhaled NO was higher at rest during OB compared to SB and NB and decreased after exercise with NB and SB. Plasma and RBC NO remained unaltered during intervention. RBC deformability increased at moderate intensity during SB. Deformability decreased at moderate and medium intensity with NB. Respiratory rate for same oxygen uptake did not differ between breathing settings.

CONCLUSION

The AlaxoLito Plus Nasal Stent may modulate deformability during moderate exercise and increase NO exhalation without major effects on oxygen uptake and performance.

Responses for blood morphological indices in a 60-km horse endurance race depending on the season

The aim of this study was to find whether the magnitude of changes in blood before and after horse endurance competitions was the same at the beginning and the end of the season and if the studied indices could be useful in assessing the impact of such changes on the length of the endurance racing season. The study was conducted on 36 clinically healthy horses. Blood samples were taken during 60-km endurance competitions in 2014, three times in total. The study revealed an increase of lymphocytes (× 1.89-2.05; P < 0.001), red blood cell count (× 1.11-1.12; P < 0.001), and a decrease in the mean corpuscular haemoglobin concentration (× 1.20-1.27; P < 0.001), red cell distribution width (× 1.11; P < 0.01), platelet concentrations (× 1.33-1.40; P < 0.05), when compared at the beginning and in the end of the horse endurance racing season. During the entire season, haematocrit values significantly increased after the race but were at their lowest in the mid-season period. The results proved a significant increase in the white blood cell and granulocyte counts following the finish of a 60-km endurance race, when comparing the values at the beginning and in the end of the horse endurance racing season, and a significant reduction in lymphocytes when comparing the values at the beginning (35.7%) and at the end (29.7%) of the season. The endurance competition season highly influences haematology indices in horses' blood, however, to determine the season's impact on the results of the race, additional studies must be conducted.

Association Between Hematological Parameters and Iron Metabolism Response After Marathon Race and ACTN3 Genotype

α-Actinin-3 (ACTN3 R577X, rs.1815739) polymorphism is a genetic variation that shows the most consistent influence on metabolic pathway and muscle phenotype. XX genotype is associated with higher metabolic efficiency of skeletal muscle; however, the role of ACTN3 polymorphism in oxygen transport and utilization system has not yet been investigated. Therefore, the aim of this study was to determine the influence of ACTN3 polymorphisms on hematological and iron metabolism response induced by marathon race. Eighty-one Brazilian amateur male endurance runners participated in the study. Blood samples and urine were collected before; immediately after; and 1, 3, and 15 days after the marathon race. Urine, hematological parameters, iron metabolism, and ACTN3 genotyping analyses were performed. The marathon race induced a decrease in erythrocytes, Hb, and Ht, and an increase in hematuria, creatinine, myoglobin, red cell distribution width, mean corpuscular hemoglobin concentration, mean corpuscular hemoglobin, direct and indirect bilirubin and erythropoietin. Moreover, an elevation immediately or 1 day after the marathon race follows a reduction 3 or 15 days after the marathon race were observed on transferrin saturation and iron and transferrin levels. Hematological parameters and iron metabolism changes induced by marathon race were not observed in XX genotypes. Hematuria and decreased erythrocytes, Hb, Ht, and iron and transferrin levels were observed only in RR and/or RX genotypes but not in XX genotypes. The percentage of runners with hematuria, leukocyturia, iron deficiency, creatinine, myoglobin, and bilirubin imbalance was higher in RR compared to XX genotypes. ACTN3 polymorphism is associated with iron metabolism and hematological responses after endurance exercise. Despite these results being based on a small sample, they highlight a protective role of the XX genotype on hematological and renal changes induced by long-distance exercise. Therefore, these findings should be further replicated.

Biomarkers of Physiological Responses to Periods of Intensified, Non-Resistance-Based Exercise Training in Well-Trained Male Athletes: A Systematic Review and Meta-Analysis

BACKGROUND

Intensified training is important for inducing adaptations to improve athletic performance, but detrimental performance effects can occur if prescribed inappropriately. Monitoring biomarker responses to training may inform changes in training load to optimize performance.

OBJECTIVE

This systematic review and meta-analysis aimed to identify biomarkers associated with altered exercise performance following intensified training.

METHODS

Embase, MEDLINE, CINAHL, Scopus and SPORTDiscus were searched up until September 2017. Included articles were peer reviewed and reported on biomarkers collected at rest in well-trained male athletes before and after periods of intensified training.

RESULTS

The full text of 161 articles was reviewed, with 59 included (708 participants) and 42 (550 participants) meta-analysed. In total, 118 biomarkers were evaluated, with most being cellular communication and immunity markers (n = 54). Studies most frequently measured cortisol (n = 34), creatine kinase (n = 25) and testosterone (n = 20). Many studies reported decreased immune cell counts following intensified training, irrespective of performance. Moreover, reduced performance was associated with a decrease in neutrophils (d = - 0.57; 95% confidence interval (CI) - 1.07 to - 0.07) and glutamine (d = - 0.37; 95% CI - 0.43 to - 0.31) and an increase in urea concentration (d = 0.80; 95% CI 0.30 to 1.30). In contrast, increased performance was associated with an increased testosterone:cortisol ratio (d = 0.89; 95% CI 0.54 to 1.24). All remaining biomarkers showed no consistent patterns of change with performance.

CONCLUSIONS

Many biomarkers were altered with intensified training but not in a manner related to changes in exercise performance. Neutrophils, glutamine, urea and the testosterone:cortisol ratio exhibited some evidence of directional changes that corresponded with performance changes therefore indicating potential to track performance. Additional investigations of the potential for these markers to track altered performance are warranted.

Resting CMRO2 fluctuations show persistent network hyper-connectivity following exposure to sub-concussive collisions

Exposure to head impacts may alter brain connectivity within cortical hubs such as the default-mode network (DMN). However, studies have yet to consider the confounding effects of altered resting cerebral blood flow (CBF0) and cerebrovascular reactivity (CVR) on changes in connectivity following sub-concussive impacts. Here, 23 Canadian collegiate football players were followed during a season using calibrated resting-state MRI and helmet accelerometers to examine the interplay between the neural and vascular factors that determine functional connectivity (FC). Connectivity-based analyses using blood oxygen level dependent (BOLD) and cerebral metabolic rate of oxygen consumption (CMRO2) mapping were used to study the DMN longitudinally. Network-specific decreases in CBF0 were observed one month following the season, while impaired CVR was documented at both mid-season and one month following the season, compared to pre-season baseline. Alterations in CBF0 and BOLD-based CVR throughout the season suggest that neurophysiological markers may show different susceptibility timelines following head impacts. DMN connectivity was increased throughout the season, independent of changes in cerebrovascular physiology, suggesting that alterations in FC following sub-concussive impacts are robust and independent of changes in brain hemodynamics. No significant correlations between impact kinematics and DMN connectivity changes were documented in this study. Altogether, these findings create a strong paradigm for future studies to examine the underlying neural and vascular mechanisms associated with increases in network connectivity following repeated exposure to sub-concussive collisions, in an effort to improve management of head impacts in contact sports.

Reduction of hemoglobin, not iron, inhibited maturation of red blood cells in male rats exposed to high intensity endurance exercises

The existence of sports anemia, induced by strenuous or long-term exercise and characterized by decreases of red blood cells (RBCs), hemoglobin and iron content, remains to be doubtful. To observe the effects of endurance exercise on RBCs and explain the underlying reason, we designed this study by observing RBCs parameters and iron metabolism in 8-weeks training rats and effects of iron supplement or protein supplement on RBCs. Results showed that erythrocyte counts, hematocrit, mean corpuscular volume and hemoglobin content decreased while RBC distribution width increased in exercised rats at later stage during 8 weeks training. But the contents of serum iron and ferritin decreased only at 1-week and 2-week and returned to normal at 4-week and 8-week. Same as iron content, apparent iron absorption rate was declined at early stage but restored to normal level at 8-week, as well as serum adrenaline, cortisol and insulin levels. Instead, the contents of total protein and albumin in serum were decreased at later stage during 8-weeks training. Furthermore, we observed that protein supplement ameliorated RBCs parameters in rats exposed to 8 weeks swimming exercise, but iron supplement had no effects on RBCs, though it obviously increased iron content of serum and the liver. Based on these results, we drew a conclusion that transient changes of iron metabolism, which may be induced by stress hormone changes, was not the reason for RBCs decrease in endurance exercises but hemoglobin reduction, induced by defects in protein supplement, impeded development of RBCs.

A Comparison of Blood Viscosity and Hematocrit Levels between Yoga Practitioners and Sedentary Adults

Elevations in whole blood viscosity (WBV) and hematocrit (Hct), have been linked with increased risk of cardiovascular disease (CVD). Endurance training has been demonstrated to lower WBV and Hct; however, evidence supporting the efficacy of yoga on these measures is sparse. A cross-sectional study was conducted examining WBV and Hct levels between yoga practitioners with a minimum of 3 years of consistent practice and sedentary, healthy adults. Blood samples were collected from a total of 42 participants: 23 sedentary adults and 19 regular yoga practitioners. Brachial arterial blood pressure (BP) was measured and the averages of 3 measures were reported. The yoga practitioner group had significantly lower WBV at 45 s^-1 (p < 0.01), 90 s^-1 (p < 0.01), 220 s^-1 (p < 0.05), and 450 s^-1 (p < 0.05) than sedentary participants. No significant group differences in Hct (p =0.38) were found. A tendency toward lower systolic BP (p=0.06) was observed in the yoga practitioner group; however, no significant group differences in BP were exhibited. A consistent yoga practice was associated with lower WBV, a health indicator related to CVD risk. These findings support a regular yoga practice as a valid form of exercise for improving rheological indicators of cardiovascular health.

Contrasting response of haematological variables between long-term training and short exercise bouts in zebra finches (Taeniopygia guttata)

Physical aerobic activity is oxygen demanding, but - particularly for birds - there is still little understanding of how blood contributes to oxygen supply under various activity levels. In a two-factorial experimental design, we investigated the long-term effect of daily flight training and the immediate effect of a short exercise bout on a set of haematological variables: haemoglobin (Hb) content, haematocrit (Hct), and red blood cell number (RBC_count) and size (RBC_area) in zebra finches (Taeniopygia guttata). For a period of 6 weeks, birds were either trained daily for 3 h in a flight arena or remained untrained. Subsequently, half of each group was blood sampled either in the resting condition or after a 5 min exercise bout in a flight-hover wheel. We found significantly lower Hb content, Hct and RBC_count compared with that in untrained controls in response to training, while RBC_area did not differ between treatments. Response to an exercise bout revealed the opposite pattern, with significantly higher Hb content and Hct compared with that in non-exercised birds. Additionally, RBC_area was significantly smaller immediately after exercise compared with that in non-exercised birds, and such short-term flexibility represents a novel finding for birds. This contrasting response in erythrocyte characteristics with respect to long-term training and short exercise bouts appears as a clear pattern, presumably underlain by changes in water balance. We infer alterations of blood flow to be involved in adequate oxygen supply. During an exercise bout, RBC_area flexibility may not only enhance oxygen delivery through improved erythrocyte surface area to volume ratio but also improve blood flow through a compensatory effect on blood viscosity.

Racial differences in hemoglobin and plasma volume variation: implications for muscle performance and recovery

Objective: To examine the effect of race differences on sprint performance, Hemoglobin (Hb), Hematocrit (Ht) and plasma volume (PV) variation in response to repeated sprint exercise. Design: Thirty-six healthy, moderately trained men and women (20.8 ± 0.2 year-old) volunteered to participate in this study. They were allocated to one of the four groups according to their gender and race: Black men's group (BM, n = 9), White men's group (WM, n = 9), Black women's group (BW, n = 9) and White women's group (WW, n = 9). All participants performed the running-based anaerobic sprint test (RAST), which consists of six 35-m sprints with 10 s of recovery in-between. Six venous blood samples were collected to determine Hb, Ht and PV levels at rest, after warm-up, immediately post- and at 5, 15 and 30 min post-RAST. Blood lactate is also sampled during the 3rd minutes of recovery. Results: The best running time was significantly shorter (P = .002) in BW compared to WW. We have observed significantly higher Hb (P = .010) and Ht (P = .004) levels in BW compared to WW during the 5th minute of recovery. During RAST, the PV decreased significantly (P = .007) in WM only. Black groups had lower (P < .05) lactate levels compared to the white subjects. During recovery, PV increase was significantly (P = .003) higher in WW compared to BW during the 5th minute of recovery. Conclusion: This study demonstrated that sprint and repeated sprint performances were different between white and black women. Differences in anaerobic performance between the groups were associated with racial differences in lactate levels and blood count among women's group during recovery time. Hence, it is important to take into account this race-related difference in hematological parameters in responses to intense efforts.