Variation of bone-related and inflammatory biomarkers after a half-marathon running in trained subjects.

Background: Marathons and ultra-marathon generally evidence an anabolic effect on bone metabolism; however, there is scarce knowledge of less demanding events as half-marathons, which, instead, is becoming one of the most popular recreational activities, rising in the number of followers all over the world.

Aim: To evaluate the trend of bone turnover biomarkers (bone-specific alkaline phosphatase BALP, osteocalcin OC, type 1 procollagen amino-terminal peptide P1NP, bone formation biomarkers; and carboxy-terminal collagen crosslinks CTx, and bone reabsorption biomarker) and vitamin D (25(OH)D) in controls (CON) with a low physical activity profile and trained runners (ATH; at baseline, after a half-marathon run, and 24-h post), and their correlation with the systemic immune-inflammation index (SII) and other cardiometabolic parameters.

Results: ATH showed higher levels of 25(OH)D and bone turnover biomarkers than CON; OC, BALP, P1NP, and CTx significantly increased after post-race (by 18, 20, 14, and 33%, respectively) as compared with baseline, and normalized at 24 h, except for P1NP which slowly decreased at 24 h; SII did not significantly change. In the whole population, all the bone turnover biomarkers were correlated with each other, 25(OH)D correlated with OC and BALP, whereas OC inversely correlated with diastolic blood pressure and 25(OH)D inversely correlated with body mass index. In the ATH group, no correlation between SII concentrations and levels of bone turnover biomarkers was found.

Conclusion: Both half-marathon training and acute responses after a running increase bone turnover biomarkers. More data are required to definitively assess if these changes are beneficial or adverse for bone health.