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.

The purpose of this study was to determine a typical reference range for the population of athletes. Results of blood tests of 339 athletes (82 women and 257 men, aged 18-37 years) were retrospectively analysed. The subjects were representatives of different sports disciplines. The measurements...

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.

The study investigated changes in myokines, heat shock proteins, and growth factors in highly ranked, young, male tennis players in response to physical workload during the competitive season and their potential correlations with match scores. Blood collections were carried out at the beginning, the midpoint, and the end of the tournament season. Data analysis revealed a significant increase in interleukin 6 and its inverse correlation with the number of lost games (r=-0.45; 90% CI −0.06 to 0.77). Neither the irisin nor BDNF level changed notably, yet delta changes of irisin across the season significantly correlated with the number of games won. The concentration of HSP27 recorded a small increase (31.2%; 90% CI 10.7 to 55.5, most likely). A negative correlation was noted between IGF-1 and HSP27 concentration at baseline (−0.70 very high; 90% CI −0.89 to −0.31, very likely). At the end of the season IGF-1 correlated positively with the number of games won (r=0.37moderate, 90% CI −0.16 to 0.73, likely) but negatively with the number of games lost (r=-0.39, 90% CI −0.14 to −0.74, likely). In conclusion our data indicated that Il-6, irisin, and growth factor IGF-1 may modify overall performance during a long lasting season, expressed in the amount of games won or lost.

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.

Wołyniec, W, Ratkowski, W, Kasprowicz, K, Jastrzębski, Z, Małgorzewicz, S, Witek, K, Grzywacz, T, Żmijewski, 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⁻¹ (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.