1. Physiology, Health & Exercise Lesson 17 z Osteoporosis- cause & effects zPrevention & role of exercise

2. 2 Osteoporosis Includes: zOsteoporosis & bone growth zEffects of exercise on bone density

3. 3 What is osteoporosis? zLong term condition. zBones become progressively more porous & brittle zLiterally means “porous bones” zIncreased risk of fractures zSometimes called the “silent thief”

4. 4 What is osteoporosis? zEven minor falls e.g. stepping off a kerb, can cause fractures zMost common sites of fractures: yWrist ySpine yHip zBones tend to break into fragments (rather than a clean break) zImpossible to reassemble, so can require surgical treatment

5. 5 What is osteoporosis? Other effects zLoss of height zCurvature of the spine zChronic back pain

6. 6 Bone density zBones is living zConstantly renewed throughout life zBones grow in size during adolescence & childhood zCan completely renew skeleton in 2 years at this stage (takes 7-10 years for adults) zFrom late adolescence bones stop growing in length & instead become stronger- more dense

7. 7 Bone density zif adequate calcium intake in diet & are physically active then: zPeak bone density- in late 20s to early 30s zAt age 35 balance between bone breakdown & new formation  stable bone density zAfter 35 bone loss increases  part of natural aging process zRate of approx 1% per year for females zAfter menopause rate loss 2-3% a year

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9. 9 Who gets osteoporosis? zMen zWomen zChildren zMost common in menopausal women z20-50% of women over 50 are affected z75% of women over 90 are affected z1 in 12 men in UK affected zMen at lower risk because tend to have larger and stronger bones

10. 10 Risk factors for osteoporosis Women zLack of oestrogen caused by yEarly menopause (before age of 45) yMissing periods for > 6 months (excluding pregnancy) as a result of over exercising or over- dieting

11. 11 Risk factors for osteoporosis Men zLow levels of testosterone

12. 12 Risk factors for osteoporosis Both men & women zDiet lacking calcium & Vitamin D zVitamin D required for absorption of calcium by digestive system zFamily history zSmoking & excessive alcohol consumption- both increase rate of bone loss zLow body weight zLong term immobility zGetting old!

13. 13 What causes osteoporosis? z99% of body’s calcium is found in skeleton zWhen diet low in calcium, body draws on reserves in bones to make up deficit zSo advantage to “bank” more calcium in bones before reach peak bone density- in late 20s to early 30s

14. 14 What causes osteoporosis? zOestrogen maintains bone tissue by stimulating the formation of new bone zOestrogen yenhances intestinal calcium absorption yLimits calcium withdrawal from bone zLow oestrogen levels yReduce the activity of bone cells yIncrease risk of calcium loss from bones

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16. 16 Exercise those bones! zBones require regular weight-bearing exercise zE.g. walking, dancing, jogging, tennis zWhy not swimming or cycling? zExercise: yPuts force through the bone to stimulate growth yStrengthens bones yStrengthens tendons, ligaments & point of attachment at joints

17. 17 Exercise those bones! zResistance exercise also strengthens bones zE.g. weight training zBed-ridden individuals have increased bone loss as do astronauts in zero gravity

18. 18 Treatment of osteoporosis zNo cure! zCan halt or reverse progress of disease with: yExercise yOestrogen in form of HRT (hormone replacement therapy) or calcium supplements zCaution choose exercise carefully if have osteoporosis – need moderate intensity- why?

19. 19 Treatment of osteoporosis zPrevention is better than cure: yRegular weight bearing exercise yAdequate dietary calcium & vitamin D zBoth before late 20s

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22. 22 Female athletes & osteoporosis zExtreme levels of exercise by young athletes can cause osteoporosis Reason zVery intensive training zRestricted diet zCombined reduce body fat zCan cause periods to stop & drop in oestrogen levels

23. 23 Female athletes & osteoporosis zWorrying as at a time of max potential bone growth zSome young athletes have bone density of women in their 70s zThese bone losses are irreversible zFemale athlete’s triad yIntensive training & yRestricted diet & yLow body fat