Weight-bearing exercise, overexercise, and lumbar bone density over age 50 years.
This cross-sectional study of 78 healthy subjects older than age 50 years was designed to examine the association between weight-bearing exercise and lumbar bone mineral content as assessed by quantitative computed tomography. In women, a strong correlation existed between bone density and the amount of exercise for up to 300 min/wk. However, 5 of 28 women exercising 300 min/wk or more had surprisingly low bone density, not explained by other factors. In 50 men, we also found a strong positive correlation between exercise and bone density for those up to age 65 years. Over age 65, 3 men had low bone density despite extremely vigorous exercise. We conclude that moderate weight-bearing exercise may increase lumbar bone density, but we raise the hypothesis that extremely vigorous exercise actually may be detrimental to bone density in individuals after age 50.
Michel
B A
BA
Department of Medicine, Stanford (Calif) University School of Medicine.
Bloch
D A
DA
Fries
J F
JF
D000368:Aged; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology*; D002118:Calcium / Q000008:administration & dosage; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000033:anatomy & histology*; D008297:Male; D008875:Middle Aged
D002118:Calcium