A comprehensive review indicates that reducing sedentary time and increasing light physical activity can significantly strengthen bones across all age groups. Conducted by the International Osteoporosis Foundation (IOF) Rehabilitation Working Group, the study highlights the importance of not only engaging in regular exercise but also minimizing hours spent sitting. Findings reveal that even modest daily activities can enhance bone health and lower the risk of fractures.
The review examined various studies, including systematic reviews and meta-analyses, to investigate the relationship between physical activity, sedentary behavior, and bone health. Professor Olivier Bruyère, Co-chair of the IOF Rehabilitation Working Group and the study’s lead author, emphasized the study’s critical message: “Bone health depends not only on engaging in regular physical activity but also on reducing the hours we spend in sedentary behavior.”
The analysis focused on two primary outcomes: bone mineral density (BMD) and fracture risk. BMD is a key indicator of bone strength, measuring the mineral content in bones, such as calcium and phosphorus. The review incorporated data across all age demographics, including children, adolescents, adults, and older individuals, and paid special attention to studies using objective measurements like accelerometers.
Impact on Children and Adolescents
The findings indicated that prolonged sitting, particularly from screen time, correlates with lower BMD at critical weight-bearing sites, such as the neck of the femur. Engaging in weight-bearing and impact activities, such as running, jumping, and resistance training, was shown to significantly enhance bone mass during growth phases. Importantly, benefits from early interventions, like school-based activity programs, were found to persist for years, though sustained activity is necessary to maintain these improvements.
Benefits for Adults and Older Adults
In adults, regular physical activity—especially moderate-to-vigorous weight-bearing and resistance training—was associated with higher BMD and a decreased risk of fractures. The review found that sedentary behavior negatively impacted BMD, particularly at the hip, femoral neck, and pelvis. Prolonged, uninterrupted sitting was more detrimental than shorter sitting periods.
For older adults, light activities such as walking or household chores were found to improve BMD and reduce fracture risk, particularly for postmenopausal women. More vigorous or resistance-based activities offered even greater benefits. The review indicated that replacing just 30 minutes of sitting with light activity measurably improved bone health, especially at the spine in women over 50.
The review highlighted that both physical activity and sedentary behavior exert independent effects on bone health. Being active does not negate the negative impact of excessive sitting. Even small adjustments, like substituting sitting time with movement, can lead to significant health improvements. The World Health Organization (WHO) guidelines recommend 60 minutes of daily physical activity for children and 150 to 300 minutes per week for adults, alongside minimizing sitting across all ages.
Professor Nicholas Harvey, President of the IOF, and Eugene McCloskey, Chairman of the IOF Committee of Scientific Advisors, jointly stated, “We urge governments, healthcare providers, and policymakers to implement comprehensive public health strategies that encourage active lifestyles while systematically reducing sedentary behaviors.”
While the review sheds light on important findings, it does have limitations. Many studies relied on self-reported data regarding physical activity and sedentary behavior, which may not be as accurate as data obtained from wearable devices. Furthermore, factors such as nutrition, body weight, and sex differences were not consistently considered, and some evidence remained inconsistent, particularly concerning how sedentary behavior affects BMD in older adults.
Despite these limitations, the review’s findings have practical implications for all age groups. Healthcare professionals are encouraged to assess physical activity and sedentary behavior during routine visits and to prescribe movement as they would medication. Public health policies should prioritize creating environments conducive to activity, such as walkable cities, active schools, and accessible gyms and parks.
The overarching message is clear: increasing daily movement and reducing sitting time can significantly benefit bone health and lower fracture risk throughout life. This study was published in the journal Calcified Tissue International.
