Osteoporosis literally means porous bone and is characterised by low bone mass and poor bone quality.
As our bones become more porous and fragile, the risk of fracture is greatly increased. The loss of bone often occurs silently and progressively. Generally there are no symptoms until your first fracture occurs.
Osteopenia is when your bones are weaker than normal but they are not likely to break easily, unlike osteoporosis.
Bone is divided into cancellous (or trabecular) bone and cortical bone. Cancellous bone is more metabolically active and is formed by interconnecting latticework. Cancellous bone is surrounded by the less delicate cortical bone.
Bone is remodelled (or turned over) throughout adult life by discrete remodelling units of osteoclasts (cells that resorb bone) and osteoblasts ( cells that lay down new bone).
After about 50 years of age, the volume of bone resorbed is greater than the volume formed in each remodelling unit. This process accelerates during menopause. This is because decreasing oestrogen levels enhances the rate of bone resolution. This continues in old age (ie over 70 years of age).
Osteoporosis prevalence increases with age , but usually has no symptoms until a fracture occurs.
Exercise and bone maintenance are inextricably linked. Exercise helps to build and maintain strong bones and prevent falls and fractures by improving balance, co-ordination, muscle strength and agility. To have an effect on bone and maximise bone adaptation, exercise needs to be
Rapid, short bursts of high intensity and/or high impact activities such as jogging, jumping and rope skipping are more stimulating to bone cells than sustained, low impact activity such as walking,
Lifting heavy weights, particularly when lifted rapidly seems more effective than lifting light weights.
Novel forces, such as changing directions and different heights of jumps are more stimulating than repetitive force patterns.
Exercising in shorts bouts with rest periods seems to be more effective than continuous, long periods of exercise.
Continuous progression of the weight moved, balance exercise difficulty and jump height is the most critical element of the exercise prescription for bone health. If the progression stops, so does the adaptation in the bone and muscle.
If you need any advice on exercise once diagnosed as osteoporotic or osteopenic consult a physiotherapist.
Graded exercise programs such as the exercises featured on Physio on a Roll are ideal for enhancing bone density and improving strength. Even exercises such as roller jumps have a low impact version ideal for building bone strength.
If you would like more information click on this link to the “exercise is medicine” fact sheet on osteoporosis