How can exercise help with osteoporosis?

In an ageing society, the prevalence of osteoporosis and osteopenia continues to increase progressively, with over 66% of Australian adults aged 50 years and over having osteoporosis or osteopenia (1). However, rates of osteoporosis or osteopenia are likely to be much higher as it often remains undiagnosed for many years which is why many people are surprised when they’re told by their doctor that they have it. Unfortunately, many people find out after they’ve sustained a fracture from a fall which most commonly occurs at the wrists, hips or spine(1).

Throughout our lifetime, our bones constantly go through a process called ‘remodelling’. Bone is living tissue with some cells breaking down the bone (bone resorption), while other cells rebuild new bone (bone formation), this is why bones can heal after a break (2). It is typically not until later in life that bone loss begins due to bone breakdown, a process that accelerates around the time of menopause in women. At the same time, bone formation tends to decrease with age in both men and women, typically failing to keep up with the increased rate of bone resorption (2). There are also many reasons as to why we lose bone mass at a faster rate which include things such as changes in sex hormone levels, lack of physical activity, inadequate nutrition(calcium and vitamin D intake), smoking and alcohol intake etc.

Another age-related change that often coincides with osteoporosis is the loss of skeletal muscle mass, physical function, and strength, otherwise known as sarcopenia. Skeletal muscle mass and strength decline in a linear fashion as we age, with up to 50% of mass being lost by the 8th decade of life, which can have significant health consequences for older adults (3). Resistance exercise -commonly referred to as weight training - is recommended as the first-line treatment for counteracting the deleterious effects of sarcopenia in older adults, which will be discussed further shortly.

What is the difference between osteoporosis and osteopenia?

Osteoporosis and osteopenia are classified based on your Bone Mineral Density (BMD). When you go for a bone mineral density scan, you will receive a T-score which represents the density of your bones compared to the average healthy adult. A T-score between -1.0 and -2.5 below the average is classified as osteopenia, meaning low bone mass, while a score -2.5 or more below indicates the presence of Osteoporosis.

What types of exercise help to build bone, and is it safe?

Bone is living tissue that responds well to mechanical loading during exercise. Two types of exercises are important for the formation of bone and/or slowing down further bone loss in addition to increasing skeletal muscle mass:

• Resistance training that progressively increases in load over time targeting the muscles that cross the hips and spine, which is where bone loss is most commonly located. Exercises should be performed at least two days per week and ideally be at a high intensity to stimulate bone formation. Resistance exercise has also been shown to be effective in reducing future falls which may result in a fracture (4).
• Impact loading, which consists of movements that expose bone to load through vertical and multidirectional impact such as running, hopping, jumping, skipping etc.

The bone remodelling process can take anywhere from 4-8 months to occur, so it is recommended to engage in these types of exercise consistently for at least 6-8 months to see improvements in bone mineral density (5). For exercise training to stimulate new bone growth, the mechanical load applied to the body should exceed that encountered during daily activities, which is why general weight-bearing exercise alone may not be sufficient (6). So, whilst regular walking is beneficial for a wide range of health benefits, it has little to no effect on the prevention of bone loss (7).

These types of exercises have not only shown to be efficacious but safe for people with osteoporosis and osteopenia. However, it is important to adopt a graded approach to these types of exercises to allow the body to positively adapt to increasing intensity over time. A recent study by Watson et al in 2018 showed that even at high intensities and heavy loads, resistance training was safe and effective for post-menopausal women with low and very low BMD (5). Traditionally people with low bone mineral density were perceived to have an increased risk of fractures with heavy loading, so more conservative approaches to resistance training were recommended. However, this trial shows that we might not need to be as conservative as we once thought and that the body can tolerate and positively adapt to high loads, even in people with very low bone mass (5).

If you have osteoporosis or you want to improve your bone health, muscle mass and strength, please get in contact with us at The Biomechanics. Our team are skilled and qualified to prescribe exercise for those with osteopenia or osteoporosis and will work alongside your GP to ensure exercise prescription is safe and effective.

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References:

1. Abimanyi-Ochom, Julie & Watts, Jennifer & Sanders, Kerrie. (2013). Osteoporosis Costing all Australians. A New Burden of Disease Analysis 2012-2022.
2. Office of the Surgeon General (US. (2004). The basics of bone in health and disease. In Bone Health and Osteoporosis: A Report of the Surgeon General. Office of the Surgeon General (US).
3. Walston, J. D. (2012). Sarcopenia in older adults. Current opinion in rheumatology, 24 (6),     623.
4. El-Khoury, F., Cassou, B., Charles, M. A., & Dargent-Molina, P. (2013). The effect of fall prevention exercise programmes on fall induced injuries in community dwelling older adults: systematic review and meta-analysis of randomised controlled trials. BMj, 347.
5. Watson, S. L., Weeks, B. K., Weis, L. J., Harding,     A. T., Horan, S. A., & Beck, B. R. (2018). High‐intensity resistance and impact training improves bone mineral density and physical function in postmenopausal women with osteopenia and osteoporosis: the LIFTMOR     randomized controlled trial. Journal of Bone and Mineral Research, 33     (2), 211-220.
6. Hong AR, Kim SW. Effects of Resistance Exercise on Bone Health. Endocrinol Metab (Seoul). 2018 Dec;33(4):435-444. doi: 10.3803/EnM.2018.33.4.435. PMID: 30513557; PMCID: PMC6279907.
7. Ma, D., Wu, L., & He, Z. (2013). Effects of walking on the preservation of bone mineral density in perimenopausal  and postmenopausal women: a systematic review and meta-analysis. Menopause, 20     (11), 1216-1226.

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