Relationship between running performance and bone mineral density

Abstract

Background: Bone mineral density (BMD) is a major determinant of fracture risk and overall skeletal health. Long‑distance running exposes bones to repetitive impact loads and is widely promoted for general health, yet previous studies have produced conflicting evidence regarding its effect on bone density. Some work suggests that distance running enhances BMD through mechanical loading, while others report reduced BMD at axial sites such as the lumbar spine.

Objective: To synthesize publicly accessible data from peer‑reviewed studies on running and bone density and to quantify relationships between running performance and BMD. We extracted and analysed data from open‑access articles available via PubMed and Google Scholar, focusing on differences between endurance runners and non‑athletes and the influence of age.

Methods: Three open‑access studies were identified. A 2019 cross‑sectional study comparing 68 marathon runners with 40 non‑active controls reported no difference in radial or tibial bone speed of sound but higher serum osteocalcin in runners[1]. A 2021 study of 103 high‑level endurance runners and 112 non‑athletes reported that female runners had higher leg BMD while male runners showed lower lumbar spine BMD[2]. A 2024 cross‑sectional study of 327 male runners and 212 inactive controls reported higher BMD in all lower‑limb segments but not upper‑limbs and noted that the BMD advantage decreased with age[3]. Data from the 2024 study were used to compute Cohen’s d and approximate point‑biserial correlations (r) between running status and BMD at various skeletal sites. Age‑specific BMD differences were analysed to examine associations between age and BMD benefit.

Results: In the 2019 study, runners averaged 48.6 ± 24.9 km per week and showed similar tibial and radial bone speed of sound to controls; however serum osteocalcin levels (a bone formation marker) were higher in runners (11–12 ng/mL versus 5–7 ng/mL)[1][4]. In the 2021 study, female runners exhibited ~4 % higher leg BMD than female non‑athletes, whereas male runners had ~9 % lower lumbar spine BMD but comparable total and leg BMD[2]. The 2024 study showed that runners had greater BMD at the whole body and lower‑limb sites (dominant leg: 1.26 ± 0.09 g/cm² versus 1.19 ± 0.10 g/cm²; nondominant leg: 1.26 ± 0.09 g/cm² versus 1.18 ± 0.10 g/cm²) but similar upper‑limb BMD[5]. Age‑stratified analysis revealed that the BMD advantage was largest in the 18–25 year group and diminished with age, with little difference in the oldest participants[6]. The computed effect sizes showed moderate positive correlations between running and lower‑limb BMD (r≈0.35–0.39) but weak correlations at the spine (r≈0.11–0.21) and upper limbs (r≈0.05) (Table 2). A scatter plot of dominant‑hip BMD difference versus age showed a strong negative correlation (r = −0.98) (Figure 1), indicating that the benefit of running on hip BMD declines sharply with age.

Conclusions: Weight‑bearing mechanical loading from running appears to enhance bone density in the lower extremities, especially in younger runners, while effects on axial sites are minimal or negative. High‑level male runners may exhibit lower lumbar spine BMD, potentially due to low energy availability or hormonal factors. Although running promotes bone formation markers, the magnitude of BMD improvement decreases with age and may depend on training volume and nutritional status. Future studies should consider individual running performance metrics (distance, pace and personal best times) and longitudinal designs to better quantify dose–response relationships between running and bone health.