How much and what kind of exercise will help keep osteopenia from progressing into osteoporosis?

Osteopenia is a precursor to osteoporosis and causes a decrease in bone mass which leads to structural changes. The weakening of bone increases the risk of fracture and can decrease quality of  life (Kim & Lee, 2019).  In order for bone to be maintained, it needs to be mechanically strained with osteogenic exercises (resistance and impact training). Studies such as this one by Kim and Lee (2019), indicate that an exercise program that induces physical stress to osseous tissues such as weight or load bearing exercises delays the reduction of bone density and can even increase bone mass.  Beck, Daly, Singh and Taaffe (2017),  report that in cohort studies, most skeletal benefits to the spine and hip from exercise was when the weight was progressively increased over time  (load was 80-85% of 1 repetition max), performed at least two times per week and large muscles crossing the hip and spine were targeted. 

Marues, Mota and Carvalho (2012) did a meta-analysis of randomized control trials.  According to their research, the largest bone mineral density increases at both lumbar spine and femoral neck were observed in protocols that combined impact activity and resistance training.  The authors of the aforementioned study as well as Beck et al. (2017), report that light walking, cycling, swimming and other low-impact activity alone are ineffective at increasing bone mineral density, but are beneficial to overall health and wellbeing.  

There are many factors involved in choosing an osteogenic exercise program that is right for you.  One of the commonalities in all of the studies listed in this summary was the importance of exercise choice, primarily regarding impact moves.  The overall health and current bone mineral density should determine the level of impact one should participate in. If you receive a dexa scan with the diagnosis of osteopenia or osteoporosis, talk to your doctor about the kind of exercise program that is best for you.  

References

Beck, B. R., Daly, R. M., Singh, M. A. F., & Taaffe, D. R. (2017). Exercise and Sports Science Australia (ESSA) position statement on exercise prescription for the prevention and management of osteoporosis. Journal of Science and Medicine in Sport, 20(5), 438–445. doi: 10.1016/j.jsams.2016.10.001 

Kim, K. H., & Lee, H. B. (2019). Effects of circuit training interventions on bone metabolism markers and bone density of old women with osteopenia. Journal of exercise rehabilitation, 15(2), 302–307. doi:10.12965/jer.1836640.320

Marques, E. A., Mota, J., & Carvalho, J. (2012). Exercise effects on bone mineral density in older adults: a meta-analysis of randomized controlled trials. Age (Dordrecht, Netherlands), 34(6), 1493–1515. doi:10.1007/s11357-011-9311-8