Why Walking and Running Are NOT Enough to Protect Women's Bones in Perimenopause

Stacy Sims dismisses the long-standing recommendation that walking or jogging is adequate for bone protection. She explains that even running, which can reach 2–2.5× body weight per stride, often falls short of the 3× BW threshold needed to robustly activate bone adaptation. The 'right kind of landing'—a skill taught in the Osteo Gains program—ensures that forces are transmitted in a way that maximizes bone stimulation while minimizing joint stress. The urgency of this protocol is highest in late perimenopause (the year before the final period) because that is when the most rapid bone loss occurs.

While the transcript mentions these factors briefly, Stacy Sims lists 'adequate protein and following circadian rhythm' alongside impact and resistance training as protective lifestyle measures. The precise mechanisms are not elaborated, but they are presented as part of the foundational toolbox that may make MHT unnecessary for women with initially healthy bone density.

This protocol reflects the algorithm Stacy Sims expressed: she starts with lifestyle and only suggests MHT when the foundation isn't enough. The distinction between using MHT for symptomology versus for bone density is important: the definitive evidence for MHT's benefit on bone is clear, but it is not a first-line preventive for those who are otherwise healthy and have good bone density. For women who cannot take MHT, the panel underscores that the magnitude of improvement from exercise is so close that they need not feel disadvantaged.

Stacy Sims pushes back against the entrenched belief that walking or running alone is enough to protect women's bones in perimenopause. She explains that both her own research and earlier work demonstrate that bone cells do not respond to the mild forces of steady-state walking (which rarely exceed 1–1.5× body weight). Instead, a load of approximately three times body weight is needed to trigger osteogenesis. This mechanistic threshold has practical implications: women need to incorporate impacts—jumps, bounds, landings—that deliberately generate supraphysiologic forces. The Osteo Gains program was designed to teach the 'right kind of landing' to safely deliver those loads. Sims emphasizes the urgency because the first acceleration in bone loss occurs in the year before the final menstrual period, so this is not merely a postmenopausal concern.

Stacy Sims draws on her direct experience with the Women's Health Initiative to caution against the emerging belief that MHT alone will keep bones 'back in my 20s.' She describes how the pendulum has swung from fear to over-enthusiasm, and she stresses that MHT is 'a tool in the toolbox,' not a cure. MHT shifts the balance toward bone formation, but it does not stop the ongoing remodeling disadvantage. Sims recommends that lifestyle changes—impact and resistance training, adequate protein, circadian rhythm alignment—form the foundation, and MHT should be considered only when those are insufficient or when a woman has symptoms or elevated fracture risk. She also notes the lack of research in the critical two-year pre-menopause window, making it dangerous to rely solely on hormones.

Jocelyn, another expert on the panel, highlights the practical significance of recent exercise trials. The Lift More trial demonstrated that postmenopausal women could gain approximately 3% in lumbar spine bone mineral density over just eight months through a protocol of heavy resistance and high-impact training. She points out that this is 'not dissimilar' to the gains observed in the estrogen-only arm of the Women's Health Initiative. This comparison is crucial for women who have contraindications to MHT (history of blood clots, certain cancers) or simply prefer not to take hormones. Sims and Jocelyn both argue that these exercise-mediated gains should be communicated more widely to counter the message that without MHT bones will inevitably deteriorate.

Jocelyn notes that too little research has been done in the specific two-year period before the final menses, yet it is during this time—the late perimenopause—when the steepest bone loss begins. Sims agrees that this is exactly when diet and exercise need to be optimized: adequate protein, circadian regularity, heavy lifting, and impact work. The implication is that waiting until menopause is diagnosed means missing the highest-risk window. This also raises the question of whether MHT is most effective for bone if started in perimenopause rather than after menopause, but that question remains understudied.

The panel emphasizes that bone mineral density is only one aspect of fracture risk. Exercise, especially the kind that incorporates varied impacts and heavy resistance, causes bone to remodel its architecture—wider periosteal surfaces, thicker cortices in loaded regions—which improves resistance to bending and torsion. This geometric adaptation is outside the scope of MHT and represents a unique benefit of mechanical loading. For women who rely solely on MHT, they may still have structurally disadvantageous bone geometry despite normal density values. This adds another reason that MHT should be paired with, rather than replace, exercise.