Testosterone, cortisol, vitamin D and oxidative stress and their relationships in professional soccer players.

BACKGROUND: The testosterone/cortisol ratio has been used in sport physiology to evaluate the balance between anabolism and catabolism; its decrease below 30% has been considered a marker of overtraining. In this framework recent studies in soccer players have investigated the relationships between testosterone, cortisol, vitamin D and reactive oxygen species, but with unconvincing results. The aim of the present study was to evaluate the behavior of such biological parameters and their relationships both in winter (the season of championship) and in summer (off-competition season), characterized by different homeostatic situations. METHODS: Twenty-seven professional male football players (Second Italian Division), were studied. Blood levels of free testosterone, cortisol, vitamin D and reactive oxygen species were evaluated in August (pre-season training) and in February, in the midseason. A comparison between these two periods was performed and for each of them the relationships between the biological parameters were evaluated. RESULTS: Blood levels of testosterone were higher during summer whereas those of cortisol were higher in winter. Vitamin D levels were higher in summer; in this season a positive significant relationship between vitamin D and testosterone was observed (P=0.001), but not in winter (P=0.592). Reactive oxygen species were higher in winter; in this season a significant positive relationship between these substances and cortisol was observed (0.000), but not in summer (P=0.325). CONCLUSIONS: In professional soccer players it was found a positive relationship between vitamin D and testosterone in summer and between reactive oxygen species and cortisol in winter. However, the question whether such results are genuine cause-effect relationships or mere casual or spurious statistical correlations is still unsolved. As matter of fact, such results could be dependent from other determinants which might drive the aforementioned biological parameters in the same direction. These conclusions must be considered valid only in relation to the experimental conditions (training workload, diet and sun exposure) of the present study.

Oxidative Stress and Abnormal Tendon Sonographic Features in Elite Soccer Players (A Pilot Study).

Objective Sound experimental data suggest that oxidative stress plays an important role in the pathogenesis of tendinopathies. However, this hypothesis in humans remains speculative given that clinical data are lacking to confirm it. Recently, a new methodology has allowed to quantify the oxidative stress in vivo by measuring the concentration of hydroperoxides of organic compounds, which have been utilized as an oxidative stress-related marker in several pathologic and physiologic conditions. Given the reliability of this test and the lack of information in subjects with tendinopathies, the aim of the present study was to assess the oxidative stress status in elite professional soccer players with and without ultrasonographic features of tendon damage. Methods In 73 elite players, blood metabolic parameters were evaluated and oxidative stress was measured by means of a specific test (expressed as U-Carr units). Therefore, an ultrasonographic evaluation of the Achilles and patellar tendons was performed. Results No significant relationships were observed between metabolic parameters and oxidative stress biomarkers. The Achilles and patellar tendons showed a normal echographic pattern in 58 athletes, and sonographic abnormalities in 15. The athletes with ultrasonographic alterations, compared to those with normal US picture, showed significantly higher U-Carr levels ( p = 0.000), body mass index (BMI) values ( p = 0.03) and were older ( p = 0.005). The difference in U-Carr values among the subjects remained significant also after adjustment for age and BMI. Conclusion The results of the present study support the hypothesis that oxidative substances, also increased at systemic and not only at local level, may favor tendon damage. Level of Evidence IV (pilot study).

Oxidative Stress and Abnormal Tendon Sonographic Features in Elite Soccer Players (A Pilot Study) / Estresse oxidativo e características ultrassonográficas do tendão anormal em jogadores de futebol de elite (um estudo piloto)

Abstract Objective Sound experimental data suggest that oxidative stress plays an important role in the pathogenesis of tendinopathies. However, this hypothesis in humans remains speculative given that clinical data are lacking to confirm it. Recently, a new methodology has allowed to quantify the oxidative stress in vivo by measuring the concentration of hydroperoxides of organic compounds, which have been utilized as an oxidative stressrelated marker in several pathologic and physiologic conditions. Given the reliability of this test and the lack of information in subjects with tendinopathies, the aim of the present study was to assess the oxidative stress status in elite professional soccer players with and without ultrasonographic features of tendon damage. Methods In 73 elite players, blood metabolic parameters were evaluated and oxidative stress was measured by means of a specific test (expressed as U-Carr units). Therefore, an ultrasonographic evaluation of the Achilles and patellar tendons was performed. Results No significant relationships were observed between metabolic parameters and oxidative stress biomarkers. The Achilles and patellar tendons showed a normal echographic pattern in 58 athletes, and sonographic abnormalities in 15. The athletes with ultrasonographic alterations, compared to those with normal US picture, showed significantly higher U-Carr levels (p = 0.000), body mass index (BMI) values (p = 0.03) and were older (p = 0.005). The difference in U-Carr values among the subjects remained significant also after adjustment for age and BMI. Conclusion The results of the present study support the hypothesis that oxidative substances, also increasedat systemicand notonlyat local level, mayfavor tendon damage. Level of Evidence IV (pilot study).

Resumo Objetivo Dados experimentais ultrassonográficos sugerem que o estresse oxidativo desempenha um papel importante na patogênese das tendinopatias. No entanto, essa hipótese permanece especulativa em humanos, dado que faltam dados clínicos para comprová-la. Recentemente, uma nova metodologia permitiu quantificar o estresse oxidativo in vivo medindo a concentração de hidroperóxidos de compostos orgânicos, que tem sido utilizada como um marcador relacionado ao estresse oxidativo em várias condições patológicas e fisiológicas. Dada a confiabilidade desse teste e a falta de informação em sujeitos com tendinopatias, o objetivo do presente estudo foi avaliar o status de estresse oxidativo em jogadores profissionais de elite com e sem características ultrassonográficas de dano tendinoso. Métodos Em 73 jogadores de elite foram avaliados parâmetros metabólicos e o estresse oxidativo foi medido por meio de um teste específico (expresso como unidades U-Carr). Por isso, foi realizada uma avaliação ultrassonográfica dos tendões de Aquiles e patelar. Resultados Não foram observadas relações significativas entre parâmetros metabólicos e biomarcadores de estresse oxidativo. Os tendões de Aquiles e patelar mostraram um padrão ecográfico normal em 58 atletas, e anormalidades ultrassonográficas em 15. Os atletas com alterações, em comparação com aqueles com quadro normal, apresentaram níveis significativamente mais elevados de U-Carr (p = 0,000), índice de massa corporal (IMC) (p = 0,03) e eram mais velhos (p = 0,005). A diferença nos valores de U-Carr entre os sujeitos permaneceu significativa também após ajuste por idade e IMC. Conclusão Os resultados deste estudo corroboram a hipótese de que as substâncias oxidativas, também aumentadas a nível sistêmico e não apenas a nível local, podem favorecer danos no tendão. Nível de Evidência IV (estudo piloto).

Circannual rhythm of plasmatic vitamin D levels and the association with markers of psychophysical stress in a cohort of Italian professional soccer players.

Adequate plasmatic Vitamin D levels are crucial to maintain calcium homeostasis and bone metabolism both in the general population and in athletes. Correct dietary supply and a regular sun exposure are fundamental for allowing the desired and effective fitness level. Past studies highlighted a scenario of Vitamin D insufficiency among professional soccer players in several countries, especially in North Europe, whilst a real deficiency in athletes is rare. The typical seasonal fluctuations of Vitamin D are wrongly described transversally in athletes belonging to teams that play at different latitudes and a chronobiologic approach studying the Vitamin D circannual rhythm in soccer players has not been described yet. Therefore, we studied plasma vitamin D, cortisol, testosterone, and creatin kinase (CK) concentrations in three different Italian professional teams training at the same latitude during a period of two consecutive competitive seasons (2013 and 2014). In this retrospective observational study, 167 professional soccer players were recruited (mean age at sampling 25.1 ± 4.7 years) and a total of 667 blood drawings were carried out to determine plasma 25(OH)D, serum cortisol, serum testosterone and CK levels. Testosterone to cortisol ratio (TC) was calculated based as a surrogate marker of overtraining and psychophysical stress and each athlete was drawn until a maximum of 5 times per season. Data extracted by a subgroup of players that underwent at least 4 sample drawings along a year (N = 45) were processed with the single and population mean cosinor tests to evaluate the presence of circannual rhythms: the amplitude (A), acrophase (Φ) and the MESOR (M) are described. In total, 55 players (32.9%) had an insufficient level of 25(OH)D during the seasons and other 15 athletes (9.0%) showed, at least once, a deficiency status of Vitamin D. The rhythmometric analyses applied to the data of Vitamin D revealed the presence of a significant circannual rhythm (p < 0.001) with the acrophase that occurred in August; the rhythms of Vitamin D levels were not different neither among the three soccer teams nor between competitive seasons. Cortisol, testosterone and TC showed significant circannual rhythms (p < 0.001): cortisol registered an acrophase during winter (February) while testosterone and TC registered their peaks in the summer months (July). On the contrary, CK did not display any seasonal fluctuations. In addition, we observed weak but significant correlations between 25(OH)D versus testosterone (r = 0.29 and p < 0.001), cortisol (r = -0.27 and p < 0.001) and TC (r = 0.37 and p < 0.001). No correlation was detected between Vitamin D and CK. In conclusion, the correct chronobiologic approach in the study of annual variations of Vitamin D, cortisol and testosterone could be decisive in the development of more specific supplementation and injury prevention strategies by athletic trainers and physicians.