Hepcidin and erythroferrone response to 3 weeks of exposure to normobaric hypoxia at rest in trained cyclists.

Purpose: The effectiveness of altitude training on haematological adaptations is largely dependent on iron metabolism. Hepcidin and erythroferrone (ERFE) are key iron-regulating hormones, yet their response to altitude training is poorly understood. The aim of this study was to analyze changes in hepcidin and ERFE under the influence of 3 weeks of the Live High-Train Low (LH-TL) method. Methods: Twenty male trained cyclists completed a 3-week training program under normoxic conditions (NORM) or with passive exposure to normobaric hypoxia (LH-TL; FiO2 = 16.5%, ∼2000 m; 11-12 h/day). Hepcidin, ERFE, hypoxia inducible factor-2 (HIF-2), ferroportin (Fpn), erythropoietin (EPO), serum iron (Fe) and hematological variables were assessed at baseline (S1), then immediately after (S2) and 3 days after (S3) intervention. Results: In the LH-TL group, hepcidin decreased by 13.0% (p < 0.001) in S2 and remained at a reduced level in S3. ERFE decreased by 28.7% (p < 0.05) in S2 and returned to baseline in S3. HIF-2α decreased gradually, being lower by 25.3% (p < 0.05) in S3. Fpn decreased between S1 and S2 by 18.9% (p < 0.01) and remained lower during S3 (p < 0.01). In the NORM group, in turn, hepcidin levels increased gradually, being higher by 73.9% (p < 0.05) in S3 compared to S1. No statistically significant differences in EPO were observed in both groups. Conclusion: Three weeks of LH-TL suppresses resting hepcidin and ERFE levels in endurance athletes. We found no association between hepcidin and ERFE after LH-TL. Probably, ERFE is not the only factor that suppresses hepcidin expression in response to moderate hypoxia, especially in later stages of hepcidin downregulation. With the cessation of hypoxia, favorable conditions for increasing the availability of iron cease.

Effect of training load on sleep parameters and biochemical fatigue markers in elite swimmers.

The effect of strenuous exercise on sleep patterns in swimmers is equivocal. Therefore, the purpose of the study was to describe possible changes in sleep parameters among elite swimmers subjected to different training loads (TL). Methods: Eighteen elite swimmers (8 females) were monitored across two high-volume preparatory 1-wk periods (P1, P2) and a lower-volume tapering 1-wk period (P3) before a major competition. Internal (the session rating of perceived exertion [sRPE]) and external TL (training duration and volume) were measured, along with several sleep indices (e.g., bedtime, get-up time, sleep time, wake after sleep onset [WASO]). Serum measurements of urea, creatine kinase (CK), testosterone and cortisol were taken before and after training sessions at the beginning (Mondays) and end (Fridays) of each micro cycle. Athlete TL decreased significantly in a stepwise manner from P1 to P2 and from P2 to P3. Of all sleep parameters, only significant differences in bedtime and get-up time emerged (P3 > P1 and/or P2). Sleep duration (~6.3 h) or quality (WASO: 41-45 min) were also unaffected by TL. CK levels declined from P1 to P3 (d = -0.8), and from P2 to P3 (d = -0.6). Positive exercise-induced changes in CK were also seen in each training period. The other biomarkers did not show the same temporal or acute patterns. Irrespective of the TL, the monitored swimmers experienced insufficient and fragmented sleep across this study. Neither sleep quality nor quantity were affected by different magnitudes of TL. Among the biochemical markers of fatigue, baseline plasma CK activity best reflected the physiological response to TL.

The impact of physical training on neutrophil extracellular traps in young male athletes - a pilot study.

Neutrophils are an important component of the innate immune response against various pathogens. However, there is a lack of research concerning the effects of short intensive training on neutrophil functions, especially neutrophil extracellular traps (NET) formation. The study aim was to determine the effects of a 19-day training cycle on innate immunity among young male athletes. Six male ice hockey players (< 20 years old) from the Polish national team were monitored across a five-day training camp and after a return to normal club training. The first blood collection took place before training (T1), the second after the training camp (T2) and the third 14 days later (T3). The counts/concentrations of blood biochemical, immune and endocrine markers were compared across each training period. Creatine kinase activity tended to increase at T2 (546 ± 216 U·L-1) when compared to T1 (191 ± 111 U·L-1; p=0.063). Neutrophil extracellular traps formation and neutrophil counts also differed between training periods (p=0.042 and p=0.042, respectively). Neutrophil counts tended to decrease, in contrast to NET formation which tended to rise, at T2 in comparison to T1 (2.51 ± 0.45 vs 3.04 ± 0.47 109·L-1; 24 ± 13 vs 8 ± 15%, respectively). No significant differences in other leucocyte counts were observed. A short period of intensive training was accompanied by some muscle damage and inflammation, as evidenced by CK and NET up-regulation, whilst neutrophil counts were diminished in the blood. Thus, neutrophils and NET could be involved in muscle damage and local inflammatory processes following intensive physical training in young male athletes.

Vitamin D and upper respiratory tract infections in young active males exposed to cold environments.

INTRODUCTION AND OBJECTIVE: Performing indoor and outdoor work in cold environments may result in various adverse effects on human health and may lead to increased risk of respiratory infection. The aim of this study was to determine the relation of vitamin D status to secretory immunoglobulin A concentration, leucocyte counts, cytokine concentrations and incidence of upper respiratory tract infection (URTI) episodes in young active men during an autumn-winter period. MATERIAL AND METHODS: The effect of work in a cold microclimate was studied among 23 young active male ice hockey players during a 19-week study period. Blood and saliva samples were collected 7 times during the study period. Incidence of URTI was evaluated using WURSS 21. White blood cell, neutrophil, lymphocyte, monocyte, eosinophil and basophil counts, concentrations of 25(OH)D, C-reactive protein, cortisol, IL-1ra, IL-10, IL-1ß and immunoglobulins A, M and G, were determined in the blood. Secretory immunoglobulin A, A1 and A2 and cortisol were analysed in saliva. Spearman's correlations were used to evaluate relationships between initial or final 25(OH)D concentration and URTI incidence, as well as the immune and endocrine markers. Differences in URTI episodes, immune and endocrine parameters between sufficient ( ≥20 ng·ml -1) and deficient (<20 ng ·ml -1) vitamin D status groups were compared with the Mann-Whitney test. RESULTS: There were no statistically significant correlations between mucosal and blood markers or URTI incidence and initial and final 25(OH)D concentrations. Immune, endocrine and URTI variables did not differ between deficient and sufficient vitamin D status groups. CONCLUSIONS: 25(OH)D concentration has no impact on mucosal and systemic immunity, nor on URTI episodes.

The Effect of Vitamin D3 Supplementation on Hepcidin, Iron, and IL-6 Responses after a 100 km Ultra-Marathon.

Deficiencies in iron and vitamin D are frequently observed in athletes. Therefore, we examined whether different baseline vitamin D3 levels have any impact on post-exercise serum hepcidin, IL-6 and iron responses in ultra-marathon runners. In this randomized control trial, the subjects (20 male, amateur runners, mean age 40.75 ± 7.15 years) were divided into two groups: experimental (VD) and control (CON). The VD group received vitamin D3 (10,000 UI/day) and the CON group received a placebo for two weeks before the run. Venous blood samples were collected on three occasions-before the run, after the 100 km ultra-marathon and 12 h after the run-to measure iron metabolism indicators, hepcidin, and IL-6 concentration. After two weeks of supplementation, the intervention group demonstrated a higher level of serum 25(OH)D than the CON group (27.82 ± 5.8 ng/mL vs. 20.41 ± 4.67 ng/mL; p < 0.05). There were no differences between the groups before and after the run in the circulating hepcidin and IL-6 levels. The decrease in iron concentration immediately after the 100-km ultra-marathon was smaller in the VD group than CON (p < 0.05). These data show that various vitamin D3 status can affect the post-exercise metabolism of serum iron.

Upper Respiratory Tract Infection and Mucosal Immunity in Young Ice Hockey Players During the Pretournament Training Period.

Orysiak, J, Witek, K, Malczewska-Lenczowska, J, Zembron-Lacny, A, Pokrywka, A, and Sitkowski, D. Upper respiratory tract infection and mucosal immunity in young ice hockey players during the pretournament training period. J Strength Cond Res 33(11): 3129-3135, 2019-The aim of this study was to determine the effects of 17 days of training during preparation for the Ice Hockey Under 18 World Championship of the Polish ice hockey national team on the mucosal immune function and monitor upper respiratory tract infection (URTI) incidence before, during, and after the competition. Twelve male ice hockey players (age, 17.7 ± 0.5 years) were recruited for this study. The first saliva and blood collection took place at the beginning of the training camp (without training at the training camp), the second one was collected on the 9th day of the training camp immediately after the intensification of training, and the third collection was performed on the 13th day of training (4 days before leaving for the World Championship) in the tapering phase. To assess the mucosal immune function, concentrations of secretory immunoglobulin A (sIgA), sIgA1, and sIgA2 were analyzed in saliva. Cortisol concentration and creatine kinase activity were determined in blood, as indicators of stress and muscle damage, respectively. The Wisconsin Upper Respiratory Symptom Survey-21 questionnaire was used to assess URTI symptoms. A significant increase in the sIgA1 and sIgA2 concentrations was observed in the third collection compared with the second time point (114.45 ± 33.00 vs. 77.49 ± 27.29 and 88.97 ± 25.33 vs. 71.65 ± 32.44 U, respectively). There were no statistically significant correlations between the URTI incidence and saliva variables. In conclusion, the tapering period positively affects the mucosal immune function, especially sIgA1 and sIgA2 concentrations, with no significant change in the frequency of URTI in young ice hockey players.

Short-Term d-Aspartic Acid Supplementation Does Not Affect Serum Biomarkers Associated With the Hypothalamic-Pituitary-Gonadal Axis in Male Climbers.

D-aspartic acid (DAA) is promoted as a testosterone (T) enhancing supplement by mechanisms involving the hypothalamic-pituitary-gonadal (HPG) axis. Here, we investigated the short-term effects of DAA on serum biomarkers of the HPG-axis in male climbers. Using a single-blinded, placebo-controlled design, 16 climbers were randomly assigned to either a DAA (3 g/day) or placebo (3 g/day) supplement for 2 weeks. The reverse treatment commenced after a 2-week washout, with all conditions administered in a balanced manner. The subjects maintained their normal weekly training across this study. Serum samples taken before and after each treatment were analyzed for T, luteinizing hormone, sex hormone binding globulin, and cortisol (C), and free T was calculated (cFT). The DAA supplement did not significantly affect serum T, cFT, and luteinizing hormone levels. Only a main effect of time on sex hormone binding globulin (6.8% increase) and C (13.6% decrease) emerged (p < .03). Significant negative associations were identified between pretest values and changes (%) in T, cFT, luteinizing hormone, and C levels with DAA and/or placebo, but these relationships did not differ between treatments (p > .46). Additional measures of physical function and serum hematology also failed to respond to DAA. In summary, a daily dose of DAA during a short training period did not influence T and selected indicators of the HPG-axis in male climbers. Other parameters linked to athletic performance and health status were also unaffected. Our findings support evidence showing that DAA (including DAA-blended supplements) at either recommended or higher dosages does not afford any ergogenic benefits for athletic males.

The Association between Iron and Vitamin D Status in Female Elite Athletes.

Vitamin D may influence iron metabolism and erythropoiesis, whereas iron is essential for vitamin D synthesis. We examined whether vitamin D deficiencies (VDD) are associated with reduced iron status and whether progressive iron deficiency (ID) is accompanied by inferior vitamin D status. The study included 219 healthy female (14-34 years old) athletes. VDD was defined as a 25(OH)D concentration < 75 nmol/L. ID was classified based on ferritin, soluble transferrin receptor (sTfR), total iron binding capacity (TIBC) and blood morphology indices. The percentage of ID subjects was higher (32%) in the VDD group than in the 25(OH)D sufficient group (11%) (χ² = 10.6; p = 0.001). The percentage of VDD subjects was higher (75%) in the ID than in the normal iron status group (48%) (χ² = 15.6; p = 0.001). The odds ratios (ORs) for VDD increased from 1.75 (95% CI 1.02-2.99; p = 0.040) to 4.6 (95% CI 1.81-11.65; p = 0.001) with progressing iron deficiency. ID was dependent on VDD in both VDD groups (25(OH)D < 75 and < 50 nmol/L). The ID group had a lower 25(OH)D concentration (p = 0.000). The VDD group had lower ferritin (p = 0.043) and iron (p = 0.004) concentrations and higher values of TIBC (p = 0.016) and sTfR (p = 0.001). The current results confirm the association between vitamin D and iron status in female athletes, although it is difficult to assess exactly which of these nutrients exerts a stronger influence over the other.

Glomerular Filtration Rate Is Unchanged by Ultramarathon.

Wolyniec, W, Ratkowski, W, Kasprowicz, K, Jastrzebski, Z, Malgorzewicz, S, Witek, K, Grzywacz, T, Zmijewski, P, and Renke, M. Glomerular filtration rate is unchanged by ultramarathon. J Strength Cond Res 32(11): 3207-3215, 2018-Acute kidney injury (AKI) is reported as a common complication of marathon and ultramarathon running. In previous studies, AKI was diagnosed on the basis of the creatinine level in serum and estimated glomerular filtration rate (eGFR). In this study, we calculated eGFR and also measured creatinine clearance after every 25 km of a 100-km run. Twenty healthy, amateur runners (males, mean age 40.75 ± 7.15 years, mean body mass 76.87 ± 8.39 kg) took part in a 100-km run on a track. Blood and urine were collected before the run, after every 25 km, and 12 hours after the run. Seventeen runners completed the study. There was increase in creatinine, urea, and uric acid observed after 100 km (p < 0.05). The mean increase in creatinine was 0.21 mg·dl (24.53%). Five runners fulfilled the AKI network criteria of AKI. The eGFR according to the modification of diet in renal disease, chronic kidney disease epidemiology collaboration, and Cockcroft-Gault formulas was significantly decreased after the run (p ≤ 0.05). Otherwise, creatinine clearance calculated from creatinine level in both serum and urine remained stable. In contrast to the majority of previous studies, we did not observe any decrease in the kidney function during an ultramarathon. In this study, the creatinine clearance, which is the best routine laboratory method to determine GFR was used. There is no evidence that long running is harmful for kidney.

Mucosal immunity and upper respiratory tract infections during a 24-week competitive season in young ice hockey players.

The aim of this study was to examine upper respiratory tract infections (URTI) and their associations with resting saliva and blood immune and endocrine parameters in ice hockey players. Twenty-seven participants (age 16.5 ± 0.5 years) completed the 24-week study period. The counts/concentrations of immune and endocrine markers were compared between healthy-prone athletes (≤2 episodes of URTI during the study period) and illness-prone athletes (≥3 episodes of URTI) and between the URTI state (when athletes had infections) and the healthy state (the time without URTI). There were no differences in concentration/counts of saliva and blood immune and endocrine parameters between the illness-prone and illness-free athletes. Athletes had significantly lower sIgA, sIgA1 and sIgA2 concentrations (sIgA: 119.88 ± 66.88, 144.10 ± 75.0 µg/ml; sIgA1: 90.2 ± 40.64, 108.44 ± 29.8 U; sIgA2: 67.58 ± 30.1, 80.3 ± 25.61 U, respectively) and significantly higher WBC, neutrophil, monocyte and eosinophil count values and IL-1ra concentration at the time when they had symptoms of URTI than in the period without symptoms of infections. There were no differences in salivary cortisol concentration between the period of URTI symptoms and the period without URTI symptoms. In conclusion, we observed lower concentrations of salivary immunoglobulins and higher levels of blood immune parameters during URTI in athletes, which may confirm the suppression of mucosal immunity and initiation responses to pathogenic infections by innate immunity.