By Eva Boland – Exercise Physiologist
Bones, we don’t often give them much thought, unless of course we break one. Did you know that if you are aged over 50 and you are female, your lifetime risk of sustaining a fracture is 1 in 2 (yep, 50%!); if you are male, your risk is 1 in 5.
Unfortunately, our bodies don’t give us early warning signs and, in many cases, the first sign of reduced bone health is a broken bone. One of the first bones to succumb is the distal radius of the wrist when an individual places their arm out to cushion a fall. If you are over 50 and this has happened to you, please speak to your GP about getting a DEXA scan.
A DEXA scan is very low-level x-ray that can tell you how strong your bones are by measuring how dense the bone is, termed bone mineral density (BMD). It compares the BMD of your bones to that of a reference person aged 20-30 years and calculates how far your bones are from that reference using standard deviations. This is termed a T Score. T scores are then used to classify your bones as either 1/ normal, 2/ osteopenic or 3/ osteoporotic.
IMPORTANT: We know there is strong relationship between BMD and your risk of fracture.
The following T score categories can help you determine the strength of your bones: 🦴💪
Osteopenia is a warning sign that the bones are beginning to lose their mineral content. It should be a call to action from you and your healthcare team. The most common sites for fracture are the spine and hip, with the majority resulting from a fall.
What about calcium and vitamin D? 🥛🌞
Bones are our body’s major storage pool of calcium, phosphorus and magnesium, which is why it’s essential you get enough of these minerals from your diet. If your dietary intake of calcium is low, your body will ‘pull’ (e.g., break down) the calcium from your bones to maintain normal blood levels. For this reason, a blood test won’t be able to determine if your dietary calcium intake is adequate or not. We know that if you are female and over 50, you need 1300mg of calcium from your diet each day; if you are male, you require 1000mg. And don’t forget vitamin D! Our bodies can’t absorb calcium without it. Your GP will analyse your blood levels to check your vitamin D status. You are aiming for 50 nmol/L or more – you may well need to supplement this, particularly in Canberra from autumn – early spring.
Risk factors for low BMD
There are many factors that influence your risk of low BMD, including both non-modifiable and modifiable risks. What we absolutely do know is that achieving a high peak bone mineral density in your teens and 20’s helps to prevent lower BMD in later life.
Non-modifiable Risk Factors: things you can’t change
• Age – as we get older, our risk increases.
• Gender – women at greater risk after menopause.
• Genetics (family history) – one of the major risk factors.
• Menopause – sharp declines in estrogen and progesterone cause accelerated bone loss.
• ‘Secondary osteoporosis’ caused by certain medical conditions (rheumatoid arthritis, celiac disease, chronic liver or kidney disease, overactive parathyroid, malabsorption) and medications (> 3 months on oral corticosteroids).
• Sustaining one fracture means you are at significant risk of sustaining another one.
Modifiable Risk Factors: things you can change (at any age!)
• Engagement in weight bearing exercise and activity.
• Low muscle mass, called ‘sarcopenia’.
• Calcium and vitamin D intake.
• Low body weight or very high body weight (obesity is not protective!).
• Alcohol intake (>3 standard drinks / day).
• Falls risk.
Why is menopause a risk factor?
We know that in the first 5-7 years post menopause, a women can lose between 10-20% of her BMD. This is a huge amount and is a key time in a woman’s life when maintaining BMD becomes the goal. The average age of menopause in Australia is 51 years and sees the main sex hormones, estrogen and progesterone, fall dramatically. Unfortunately, these hormones are key for maintaining bone mass, architecture, and strength. Without them, the rate of bone resorption (break down) exceeds the rate of renewal, and we see an accelerated rate of loss. Hormonal therapy is very useful in the first 10 years post menopause for maintaining BMD, and even better when combined with resistance and impact-based exercise. When a woman is 10 or more years post menopause, her rate of bone loss slows to between 0.5%-1% per year, which may not seem like a lot, but absolutely is. Often the goal of treatment becomes preventing this loss, rather than gaining more bone mass. Therefore, if your follow up DEXA shows ‘no change’- pat yourself on the back- this is a win!
So, what exercise is best? 🏋️♀️
In a nutshell – you need to lift heavy things. Activities like walking, swimming, tai chi, and cycling will not be enough to build or maintain bone. We know from multiple exercise studies that progressing to heavy lifting – things so heavy that you can’t lift them more than 6 times in a row – works. Unless you are an absolute beginner, 3 sets of 15 repetitions will not be enough. You’ll need 3 sessions per week, lasting between 20-60 minutes, to see changes at the 12–18-month mark on your follow up DEXA.
We also know that bones respond very well to impact exercise, things like stamping on the spot, jumping on the spot, step up/down etc. “But I’ve never done any strength or impact training in my life” I hear you say. This is where working with a trained professional like an Exercise Physiologist or Physiotherapist, is key! We can steadily and safely help progress you from complete beginner to feeling competent lifting heavy things. We will also ensure you improve your balance to reduce your risk of falling.
You don’t need to join a gym to build your bones, you just need a dash of commitment, consistency, and the right help! 🤝
Check out these simple exercises you can do at home to increase your bone density:
Daly RM, Dalla Via J, Duckham RL, Fraser SF, Helge EW. Exercise for the prevention of osteoporosis in postmenopausal women: an evidence-based guide to the optimal prescription. Braz J Phys Ther. 2019 Mar-Apr;23(2):170-180.
Bone Source (National Osteoporosis Foundation) Health professional tool kit: https://www.bonesource.org/healthcare-professionals-