ECSS Paris 2023: OP-PN33
INTRODUCTION: In addition to a well-documented role in neurodegenerative diseases, brain-derived neurotropic factor (BDNF) has also been studied in military environments, where mental stress, energy and sleep deficit, and prolonged physical activity are continuous and fluctuating stress factors (Beckner et al. 2022). Reduction in body mass and remarkable hormonal responses are often observed simultaneously in this type of trainings (Ojanen et al. 2023). BDNF concentration typically decreases in strenuous environments, but the function of this neurotrophin is not clearly understood. Thus, the purpose of this study was to a) describe BDNF responses in multi-stress military training, b) examine associations between BDNF, body composition and biomarkers, and c) study the effect of 36 hours’ recovery on these outcomes during training. METHODS: Two groups of male soldiers were studied: FEX (n=42, 19.5 ± 0.8 years, 179 ± 6 cm, 74.4 ± 10.8 kg) had continuous winter field training with energy and sleep deficit, while REC (n=26, 19.7 ± 1.2, 181 ± 6 cm, 78,2 ± 9.6 kg) had 36-hours active recovery phase in the middle of training (days 6 to 8). Body composition was measured via bioimpedance, and blood samples for BDNF and biomarkers (testosterone, cortisol, IGF-1, leptin, ghrelin, adrenalin, noradrenalin, prolactin, sex hormone binding protein) were collected at days 1, 6, 8, 10 during training. Linear mixed model was used for evaluating main effects and interactions between time and group, and Spearman correlations with FDR adjustments for associations between BDNF, body composition and biomarkers. Statistical significance was set as p<0.05. RESULTS: BDNF decreased in both groups during training and systematically lower BDNF values were found in the REC group compared to the FEX group (main effects with time p<0.001 and group p=0.011). No associations were found between BDNF, body composition or metabolic biomarkers at any time points, and further, changes in BDNF concentration did not associate with changes in body composition or biomarkers. CONCLUSION: A decrease in BDNF levels was found during multi-stress military training in both groups, regardless of the active recovery period of the REC group. Higher initial body mass was observed in the REC group, but none of the body composition variables, or biomarkers, explained the systematic difference in BDNF levels observed in this data. Further research is needed to elucidate the role of BDNF in anabolic and catabolic processes in multi-stress military environments. Beckner ME, Main L, Tait JL, Martin BJ, Conkright WR, Nindl BC. 2022. Circulating biomarkers associated with performance and resilience during military operational stress. Eur J Sport Sci. 22(1):72-86. Ojanen, T., Pihlainen, K., Yli-Renko, J., Vaara, J., Nykänen, T., Heikkinen, R. & Kyröläinen, H. (2023). Effects of 36-hour recovery on marksmanship and hormone concentrations during strenuous winter military survival training. BMC Sports Science, Medicine and Rehabilitation, 15(1).
Read CV Tarja NykanenECSS Paris 2023: OP-PN33
INTRODUCTION: Physical exercise interventions can cause neuroendocrine activation, which in turn increases salivary cortisol concentrations (Budde et al., 2015). We aimed to investigate the influence of different acute exercise interventions on cortisol levels. Here, we distinguished between a coordinative exercise and an endurance exercise. To our knowledge, there have been no studies to date on whether the hypothalamic-pituitary-adrenal (HPA) axis differ between an acute coordinative exercise and an acute endurance exercise of the same intensity and duration. The purpose of this study was to examine the effects of these two different acute physical stressors on cortisol levels, specifically focusing on an intraindividual comparison between an acute coordinative and acute endurance exercise. METHODS: Sixty-one students between eighteen and thirty years of age were included in the study and completed first a coordinative exercise and seven days later an endurance exercise of the same intensity and length which was self set on the first day, with a mean heart rate of 75-80% max over a period of 15 min. To measure changes in HPA axis activity, saliva samples were collected before and 5 and 30 minutes after exercise. The exercise intensity was controlled individually on a heart rate (HR) monitor as was the Rate of Perceived Exertion (RPE) using the Borg Scale (Borg and Loellgen, 2001). The saliva was stored at -20C° and analyzed within the next month for cortisol. RESULTS: The results showed that the coordination exercise (co) produced a higher cortisol release than the endurance exercise (en). While the mean intensity was: HR 143 and the RPE was 13.9 co vs. 13.8 en. CONCLUSION: We argue that interventions such as a coordinative exercise require a higher cognitive component, which results in stronger cortisol release than an endurance exercise of the same intensity and length and RPE level. Neither the motor fitness level nor the physical activity level hat an impact on the cortisol secretion. Thus, the type of acute physical exercise would be a psychophysiological factor in determining the neuroendocrine stress response and may be of interest in further research to sufficiently elucidate the proximate mechanisms of the stress reactions from acute physical exercise. Until now these results could only be obtained when we observed a blunted cortisol awakening response (CAR) due to coordinative vs endurance training (Wegner et al., 2019). References Borg and Loellgen (2001), “Borg’s Perceived Exertion and Pain Scales,” vol. 52. Budde et al., (2015) The cortisol response to exercise in young adults. Frontiers in Behavioral Neuroscience. 3;9:13 doi: 0.3389/fnbeh.2015.00013 Wegner et al., (2019) Effects of different types of exercise training on the cortisol awakening response in children: A Randomized Controlled Trial. Frontiers in Endocrinology. doi: 10.3389/fendo.2019.00463
Read CV Henning BuddeECSS Paris 2023: OP-PN33
INTRODUCTION: The menstrual cycle (MC) is characterized by fluctuations of the sex steroids estrogen and progesterone. However, the cyclic fluctuations of anabolic steroid hormones such as testosterone and androstenedione, which are secreted from both ovaries and the adrenal cortex, and the influence of hormonal oral contraception (OC) are largely unknown in elite female athletes. As the phases of MC might influence athletic performance and strength training adaptations1, a deeper understanding of the secretion and metabolism of anabolic sex steroid hormones through the MC is needed. The present study aimed to investigate the plasma levels of these hormones using capillary blood sampling as a new sampling method during MC in elite athletes with and without OC (wOC/noOC). METHODS: 22 elite track and field athletes participated in a longitudinal study of MC monitoring in sports. 12 athletes with normal MC (n=19 cycles) and 5 athletes with OC (n=10 cycles) (26±6 y, 172±5 cm, 68±7 kg) were included in the analysis. In addition to the progesterone measurement, the intravaginal body temperature was measured daily for 24 hours to determine ovulation. Further, athletes collected capillary EDTA blood before training each Monday, Wednesday, and Friday. Plasma steroid hormones were analyzed by LC-MS/MS. Linear mixed models were used to compare testosterone (T) and androstenedione (A) during different phases of MC/noOC (7-phases: menstruation, mid and late follicular phase (FP), ovulation, and early, mid and late luteal phase (LP) and wOC (7-“phases”: 28 days/ 7). The average of T and A was used for statistical comparison between noOC and wOC using the Mann-Whitney-U test. RESULTS: In noOC plasma levels of T and A were significantly higher during ovulation compared to menstruation (T: ovulation: 0,44±0.23 ng/ml; menstruation: 0.30±0.12 ng/ml; 95% CI [0.03 0.18], p=0.032; A: ovulation: 1.45±0.65 ng/ml; menstruation: 0.88±0.38 ng/ml; 95% CI [0.22 0.68], p<0.001). In addition, A differed between ovulation and mid FP, late FP, mid LP, and late LP (ANOVA summary, p=0.012). Further, steroid hormone concentrations in wOC did not differ between the respective “phases”. Median A concentration was higher in noOC compared wOC (noOC: 0.84 (0.6, 1.06) ng/ml; wOC: 0.97 (0.79, 1.29) ng/ml; 95% CI [-0.27 -0.10], p<0.001), while median T did not differ between groups. CONCLUSION: In regular menstruating athletes plasma T concentrations were about 45% and A concentrations about 60 % higher around ovulation compared to menstruation. These findings of higher anabolic steroid hormone concentrations around ovulation support the rationale for periodizing training to MC. Results between athletes without and with OC are contradictory concerning T and A. Hormonal changes in the MC were highly variable and require individual analysis and interpretation. This project was funded with research funds from the Federal Institute for Sports Science based on a decision by the German Bundestag. 1. Alexander et al., 2022
Read CV Jana SipplECSS Paris 2023: OP-PN33