Our bones are a living organ which provide our body with a hard skeleton giving us shape, structure and protection to our internal organs. These bones are made up of both collagen and calcium giving both the flexibility and strength that we need to move. They are constantly remodelling themselves, both breaking down old bone and building up new bone.
Bone formation originally starts as a foetus and completes around late adolescence or early adulthood. During this time, it is important to maximise our peak bone mass (maximum size and strength of our bones). While our genes play a role in determining peak bone mass, what we eat and how we exercise can change the level you reach. There is a limited time frame in which this can be influenced. The best time for building bone mass is during our growing years as most people will reach their peak around their 20’s or 30’s.
By the age of 40 our bone mass starts to decline. This is unavoidable, but we can influence the rate that it happens by staying healthy and ensuring that we have enough calcium within our diet, enough vitamin D to aid absorption and perform appropriate exercise.
99% of the bodies calcium is found in bones. Calcium is not only essential for maintaining both the strength of bones and building new bone but also for keeping the heart, muscles, blood and nerves functioning. Bones are the bodies calcium “bank” therefore if you do not take in enough calcium then your body draws calcium out of your bones to top it up. If this continues then slowly your bone density would decrease.
Osteoporosis Australia recommends that the best way to get enough calcium is through adequate calcium rich food intake. The level that you need differs depending on life stage. Calcium uptake becomes less efficient as we get older there you need to take in more calcium to maintain adequate levels.
We don’t absorb all the calcium that we eat but there are reasons that can lead to impaired uptake. Low vitamin D levels, lots of caffeine or alcohol, certain diets or medical conditions can all decrease the amount of calcium absorbed.
Vitamin D helps the body absorb calcium. While this can be absorbed from diet and supplements, sunlight (exposure to Ultraviolet B- UVB) is the most common source. Surprisingly the amount of sun exposure needed is still relatively low though this can vary depending on your skin type or the season.
Now you might be wondering, how do you manage to get enough UVB exposure to produce vitamin D without increasing your skin damage. Osteoporosis Australia and Cancer Council both recommend avoiding the midday sun when the UV level is 3 or above. The number of minutes you need to spend in this differs significantly with location and season.
Our bones adapt to the amount of stress that is put through them. With regular impact exercise our bones become stronger. Weight-bearing exercise is therefore particularly important for the maintenance of bone mass.
Exercise to be effective must be regular and not just a once off. Current general guidelines state at exercise should be completed at least three times per week. While swimming and cycling are good for general cardiovascular health they are unlikely to change your bone health. Exercise such as walking, running, resistance training or tennis have increased impact therefore can be better for maintaining bone density. It is also important to vary the type of exercise you do and progress this exercise over time.
Contact the team at Bend + Mend Physiotherapy in Sydney’s CBD if you have any questions regarding bone health or you would like to discuss exercise to prevent bone mass decline.