Which exercises best support bone health? Evidence from 124 randomized trials

News summary

ScienceAlert reported on a BMJ network meta-analysis suggesting that both exercise type and dose matter for maintaining bone mineral density. Across 124 randomized trials, brisk walking or jogging and combined aerobic-resistance training were among the modalities showing the most favorable BMD results. Effects were generally modest, and certainty of evidence ranged from low to moderate depending on the outcome.

Brisk walking or jogging ranked among the more favorable options for lumbar-spine, femoral-neck, and total-hip BMD, while combined aerobic-resistance exercise also performed well, especially for the lumbar spine. Dose-response modeling suggested that around 600 MET-minutes per week—roughly 2–3 hours of brisk walking or jogging—may approach clinically meaningful BMD changes for some sites. Fracture findings were more limited and lower-certainty.

The study does not support a single fixed prescription for everyone. For many adults, combining weight-bearing activity such as brisk walking with resistance training may be a practical approach. People with osteoporosis, prior fractures, or mobility limitations may need exercise type and intensity adapted to their circumstances.

The meta-analysis combined heterogeneous trials differing in exercise modality, duration, and population. Many estimates were supported by low-to-moderate certainty evidence, and subgroup analyses relied on trial-level rather than individual-level data. Bone mineral density is also a surrogate outcome and does not by itself guarantee fracture reduction.