Media release

Profiles

‘Invest in your bones:
Make it or Break it’ study highlights

About bones

• Bones begin to thin and weaken as early as age 40
• Most people reach their peak bone mass and bone strength in their 20s
• Bone density remains stable during adulthood and then begins to decline
• Cells continuously renew bone tissue in a well-ordered cycle of breakdown and rebuilding called “bone turnover”
• Bone turnover allows bone to gain strength in response to an increase in load and conversely, bone strength is reduced if the load is reduced

Bone mass and exercise

• Exercise helps to build and maintain strong bones, prevent falls and fractures and speeds rehabilitation
• Bone mass and exercise are inextricably linked
• Exercise builds strong muscles which in turn build strong bones
• Exercise is just as important as a healthy diet, and intake of vitamin D and calcium for the healthy functioning of bone
• Smoking and excessive alcohol intake can contribute to bone loss

About muscles

• Bones help convert muscle power into directional motion
• Improving strength of muscles will cause strengthening of bones, i.e. stronger muscles, stronger bones
• Less use of muscles results in a cutback in the production of new, healthy bone tissue, i.e. weaker muscles, weaker bones
• Less use of muscles means less control exerted by the nervous system, lower reflexes and an increased risk of stumbling or falling
• Exercise improves muscle control, balance and coordination, and reduces risk of falling or suffering a fracture during a fall

Bone health exercise tips

• Bones need a variety of brief, frequent loads every day
• Weight-bearing and high impact exercise is required to stimulate bone formation, e.g. sports that involve lifting weights, running, sprinting, jumping and skipping
• Exercises for bones include walking, jogging, dancing, tennis, volleyball, strength training or resistance training programs
• Intense exercise of short duration builds bone most efficiently e.g. short sprints are better than a long, slow walk
• Two short exercise sessions separated by 8 hours are better than one long one
• If exercise needs to be reduced, it is better to reduce the length of the sessions rather than the number of weekly sessions
• Exercise regimens should be tailored to individual abilities and circumstances
• Don’t overdo it – both male and female athletes who practice excessive exercise without adequate caloric intake are at heightened risk of osteoporosis
• Those who train hard while trying to keep their weight below a certain level for competitive reasons are at particularly high risk of osteoporosis
• Low impact exercises such as cycling or swimming will not have the same ‘loading’ effect on bones even though they are excellent for overall health and muscle strength

The young

• Children should get plenty of exercise to help build their peak bone mass
• How long bones stay healthy depends on how well they were made to begin with
• In girls the bone tissue accumulated during the ages of 11 to 13 approximately equals the amount lost during the 30 years following menopause
• Physically active young girls gain about 40 per cent more bone mass than the least active girls of the same age
• Boys who do vigorous daily activities have 9 per cent more bone area and 12 per cent more bone strength than less active boys

Adults

• Exercise maintains bone density in adults
• It’s never too late to start exercising
• People who exercise should evaluate whether or not their exercise program contributes to bone health
• Studies on “terranauts”, volunteers who remain bed-ridden for weeks or even months, have shown a 15 per cent loss of bone mineral density without exercise
• Women who sit for more than 9 hours a day are 50 per cent more likely to have a hip fracture than those who sit for less than 6 hours a day
• Women who are sedentary have a much lower Bone Mineral Density (BMD) and reach the BMD fracture threshold at a much earlier age than active women

The elderly

• Exercise maintains bone density in the elderly and speeds rehabilitation after fractures
• Strength and balance training are important in preventing the falls which cause fracture among the elderly
• Muscle strengthening exercises can help rebuild bone in those who have developed osteoporosis
• Back strengthening exercises can reduce the chance of getting a fracture by almost threefold
• Postmenopausal women who exercise (2 year back program study) are half as likely to have wedged vertebrae than postmenopausal women who don’t exercise
• People over 80 who exercise regularly have 20% less falls and approximately 35% fewer falls resulting in injury, compared to the elderly who do not exercise
• Patients who exercise after a hip fracture are significantly better at a variety of daily living functions, walking on average 50% and climbing stairs about 30% faster than patients who do not exercise.
  

------------------------------------------------------------------------

For more information about osteoporosis, World Osteoporosis Day and the IOF landmark study, call Osteoporosis Australia on 1800 242 141 or visit www.osteoporosis.org.au.

References

Invest in your bones. Make it or Break it. ‘How exercise helps to build and maintain strong bones, prevent falls and fractures, and speed rehabilitation. 2005. Written on behalf of the IOF Committee of Scientific Advisors by Helmut W. Minne, MD, Chairman IOF Committee of National Societies; Clinic “Der Fürstenhof”, Center of Endocrinology and Metabolic Bone Diseases, Bad Pyrmont, Germany; German Academy of the Osteological & Rheumatological Sciences.