Effect of changes in weight-bearing exercise on lumbar bone mass after age fifty.
This two year longitudinal study of 40 healthy subjects over age fifty (27 exercisers, 13 non-exercisers) was designed to evaluate the impact of weight-bearing exercise on lumbar bone mineral density as assessed by quantitative computed tomography. In both males and females exercising at moderate levels, a high correlation was found between changes in exercise and changes in bone density (r = 0.78 and 0.91, respectively P less than 0.002). For extreme levels of exercise (greater than 300 min/week in females over age fifty, and greater than 200 min/week in males over age seventy) bone density was low, confirming earlier cross-sectional results. Subjects without change in their exercise levels and non-exercisers lost similar amounts of bone. Increasing body mass index was identified as a protective factor with regard to lumbar bone loss. We conclude that in exercisers continuation of weight-bearing exercise is mandatory to prevent excessive bone loss. Extreme levels of exercise may be detrimental to bone density in subjects over age fifty years.
Michel
B A
BA
Department of Rheumatology, University Hospital, Zürich, Switzerland.
Lane
N E
NE
Bloch
D A
DA
Jones
H H
HH
Fries
J F
JF
D015519:Bone Density / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000453:epidemiology*; D015663:Osteoporosis, Postmenopausal / Q000453:epidemiology*; D012044:Regression Analysis; D012420:Running; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016474:Weight-Bearing / Q000502:physiology