Bone health in sedentary and high- and low-impact exercising postmenopausal women

INTRODUCTION: Postmenopausal (PM) women experience rapid bone loss and increased fracture risk, however, exercise recommendations for preserving bone health in this population are unclear at this time. Weight-bearing exercise is known to stimulate bone formation; however, it is uncertain whether lifestyles that include frequent participation in high-impact activities such as high-intensity exercise training (HIT), and running, and low-impact exercise (e.g. swimming) provide differential skeletal benefits. Thus, this study investigated Trabecular Bone Score (TBS), Fracture Risk (FRAX), and bone mineral density (BMD) in PM women engaging in different exercise modalities and examined the influence of lean mass (LM) on bone outcomes. We hypothesize that bone outcomes will differ across groups. METHODS: Fifty-eight PM women aged 45-70 yrs were included in this study. Women were classified as runners (n=20), swimmers (n=12), or HIT (n=14) based on their primary exercise. Women were classified as sedentary (n=12) if they did not engage in >150 mins of moderate or >75 mins of vigorous physical activity per week. Exclusion criteria included an osteoporosis diagnosis, body mass index (BMI) >30 kg/m 2 , hysterectomy or oophorectomy, and use of hormone replacement therapy or any prescribed drugs impacting bone health. Dual-energy X-ray absorptiometry measured body composition and BMD. TBS and FRAX were assessed via TBS iNsight software and the Fracture Risk Assessment Tool, respectively. ANCOVA with Bonferroni post-hoc assessed group differences in bone outcomes while controlling lean mass (LM), years PM, and past exercise. Linear regression examined relations of LM with bone outcomes while controlling for years PM and past exercise. RESULTS: Age (59.3±5.0 yrs) and years PM (8.8±4.8 yrs) did not differ across groups. Sedentary women (69.6±10.4 kg) were heavier than the runners (59.4±9.7 kg; p=0.02) and had a higher BMI (26.1±2.9 kg/m 2 ) than runners (22.2±2.3 kg/m 2 ; p< 0.01) and HIT (21.7±2.3 kg/m 2 ; p< 0.001). There were no significant differences in total BMD (p=0.97), TBS (p=0.23) hip FRAX (p=0.66), or major osteoporotic FRAX (p=0.53) between the women who were sedentary, runners, swimmers and HIT. Independent of group, total LM was positively associated with total BMD (adjusted R2 = 0.200; p< 0.001), as well as BMD at the arm (adjusted R2 = 0.198; p< 0.001), leg (adjusted R2 = 0.168; p< 0.001), trunk (adjusted R2 = 0.048; p=0.04), and femoral neck (adjusted R2 = 0.154; p=0.003). LM was also inversely associated with hip FRAX (adjusted R2 = 0.270; p=0.01). CONCLUSIONS: Bone health outcomes (i.e., BMD, TBS, FRAX) did not differ by exercise modality in postmenopausal women. However, total LM was positively associated with BMD at multiple sites and was inversely associated with hip fracture risk. These findings may suggest that preserving LM may be of greater importance for bone health than specific exercise type in postmenopausal women. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.