Our skeletal system is a unique, complex and amazing structure. Most of us have 206 bones in total, although a small number of people have an extra rib and others have an extra bone or two in their hands or feet.
Our skeleton is also extremely efficient, despite supporting the weight of our entire body. The dry weight of a healthy human skeleton averages only around 7% of total body mass – so blaming excess weight on ‘big bones’ is not exactly an excuse!
For a relatively light structure the skeleton is also very strong, particularly under compressive loads. Under strict conditions a healthy human adult’s femur (thigh bone) can be capable of withstanding compressive loads of up to 5 x 104 N which is over 5,000kg of load under the force of gravity.
However, with age comes the potential for weakness in our bones. That’s why it’s important to start taking steps to improve or maintain your bone density as early as possible, particularly for women where reduction in bone density can start early in life.
Osteopenia is the precursor to Osteoporosis and is characterised by the decrease in bone cell density. This can be due to a number of factors such as physical inactivity, a history of eating disorders, poor diet or nutrient absorption (specifically lack of Calcium and Vitamin D) and smoking. Females are more at risk than males due to hormonal differences, particularly during menopause.
A reduction in bone density can eventually lead to Osteoporosis and may result in a higher incidence of fractures and postural deformities. Until a sudden trauma or incident, you may not even know that you are at risk or that your bone density has decreased.
If you feel you may be at risk you can evaluate your bone mineral density with very good accuracy by undertaking a DEXA scan. With a referral by a GP, some people may even be eligible to claim the Medicare rebate. Alternatively, you can go directly without a referral to a facility with DEXA availability.
Maintenance of bone density is preferable to trying to address the problem after symptoms have already presented, so there are some key strategies to consider to maintain healthy bones:
Getting adequate calcium from dairy or fish with edible bones such as sardines can assist in strengthening bone. Vegans may choose options such as spinach, kale and almonds.
Exposure to the sun in small doses is essential for Vitamin D, but it’s extremely important not to overdo it and risk sunburn and skin cancers.
Exercise is also critical to bone health and should involve impact or ground force. Activities like running and resistance training in the gym provide the necessary force to strengthen bone. With adequate nutrition our bones strengthen in response to the lines of force generated by these activities, becoming stronger and less prone to fracture.
Activities like swimming or cycling, while good for general fitness, are not appropriate to improve bone density because they lack impact. If it’s an option for you, a personal trainer or fitness professional such as an Exercise Physiologist will be able to assist with exercise that are most appropriate for you.