Calcified Tissue International

, Volume 36, Supplement 1, pp S146–S150

Disuse osteoporosis: Physiological aspects

  • G. Donald Whedon
Article

DOI: 10.1007/BF02406148

Cite this article as:
Donald Whedon, G. Calcif Tissue Int (1984) 36(Suppl 1): S146. doi:10.1007/BF02406148

Summary

Immobilization in plaster, bed rest, and the weightless state all result in calcium loss which if continued for a few months will result in detectable demineralization of the lower extremities. The upper extremities are “different” bones (presumably differently programed genetically), for they have not been seen to develop X-ray-detectable demineralization except after several months of severe paralysis. The substantial losses of calcium in inactivity are accompanied by sizeable losses of nitrogren, reflective of muscle atrophy. Hence, we do not know how much of the bone loss in disuse is mediated by diminished direct physical forces on bone, how much by decreased muscle pull on periosteum, and how much perhaps by circulatory or other changes.

Key words

Space flight weightlessness Bed rest Immobilization Demineralization 

Copyright information

© Springer-Verlag New York Inc. 1984

Authors and Affiliations

  • G. Donald Whedon
    • 1
  1. 1.The Kroc FoundationSanta Ynez