High-intensity sports raise bone markers by up to 46%

Semmelweis University researchers reported in a Nov. 11 Sports Medicine - Open journal article that high-intensity sports raised bone-formation markers by up to 45%-46% in a meta-analysis of 24 clinical studies.

The review, covering 1,238 healthy adults, suggests exercise style may matter for bone metabolism, but the evidence is indirect because it measured blood signals rather than long-term bone density or fractures.

The strongest responses appeared in activities such as recreational football and handball, which involve repeated acceleration, deceleration, turning and directional changes. The researchers compared those responses with endurance, resistance and mixed training programs.

Blood markers are chemicals measured in blood that can reflect bone remodeling, the process in which old bone is replaced with new bone. The release said these markers can change within weeks, while bone mineral density usually takes longer to shift.

"What makes our study unique is that we examined not only the type of exercise - whether endurance, resistance, or combined training - but also exercise intensity, frequency, and duration. Our goal was to determine which forms of exercise stimulate bone metabolism most effectively and which appear to be less beneficial from this perspective," Péter Ferdinandy, Vice-Rector for Science and Innovations at Semmelweis University and senior author, said in the release.

The finding cuts against a common assumption that gym-based strength work is the main exercise tool for skeletal health. Viktória Barna, a PhD student at Semmelweis University and first author, said: "The most surprising finding was that resistance training did not produce a significant effect on markers of bone metabolism, even though several professional guidelines recommend this type of exercise for maintaining bone health. Likewise, low- or moderate-intensity endurance exercise, such as walking or jogging, showed no meaningful long-term effect."

That does not mean walking, jogging or conventional resistance training lack value. The Semmelweis release said those activities still have broader health benefits, even if they produced smaller changes in the bone-related markers measured in this review.

The study cannot show that higher-intensity sports were linked to fewer fractures, lower osteoporosis risk or improved bone density in the participants. It also applies to healthy adults in the clinical studies reviewed, not necessarily to people with established osteoporosis, cardiovascular disease, musculoskeletal problems or metabolic conditions.

Nóra Sydó, clinical specialist and co-author, said low-intensity exercise alone may be insufficient to stimulate bone metabolism, while higher-intensity exercise "may trigger early beneficial changes in bone formation, potentially helping to slow bone loss and support healthy aging."

The researchers said people with cardiovascular, musculoskeletal or metabolic conditions, and those who already have osteoporosis, should seek medical guidance before starting a more strenuous exercise routine.

Source: journal article, Sports Medicine - Open, 2026; Semmelweis University release via ScienceDaily, Nov. 11.

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