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Human aging, muscle mass, and fiber type composition

Lexell, Jan LU (1995) In Journals of Gerontology. Series A: Biological Sciences & Medical Sciences 50. p.11-16
Abstract
To assess the age-related loss of muscle mass and to determine the mechanisms behind this aging atrophy, the muscle structure and fiber type composition have been estimated, using invasive and noninvasive techniques. Limb muscles from older men and women are 25-35% smaller and have significantly more fat and connective tissue than limb muscles from younger individuals. Comparisons of muscle biopsies from younger and older individuals reveal that type 2 (fast-twitch) fibers are smaller in the old, while the size of type 1 (slow-twitch) fibers is much less affected. Studies of whole muscle cross sections also show a significantly smaller number of muscle fibers, a significantly lower relative type 2 fiber area, and a significant increase in... (More)
To assess the age-related loss of muscle mass and to determine the mechanisms behind this aging atrophy, the muscle structure and fiber type composition have been estimated, using invasive and noninvasive techniques. Limb muscles from older men and women are 25-35% smaller and have significantly more fat and connective tissue than limb muscles from younger individuals. Comparisons of muscle biopsies from younger and older individuals reveal that type 2 (fast-twitch) fibers are smaller in the old, while the size of type 1 (slow-twitch) fibers is much less affected. Studies of whole muscle cross sections also show a significantly smaller number of muscle fibers, a significantly lower relative type 2 fiber area, and a significant increase in fiber type grouping with increasing age. These results indicate a gradual decrease in size/volume with advancing age, accompanied by a replacement by fat and connective tissue. This aging atrophy seems to be due to a reduction in both number and size of muscle fibers, mainly of type 2, and is to some extent caused by a slowly progressive neurogenic process. (Less)
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organization
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type
Contribution to journal
publication status
published
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in
Journals of Gerontology. Series A: Biological Sciences & Medical Sciences
volume
50
pages
11 - 16
publisher
Gerontologial Society of America
external identifiers
  • pmid:7493202
  • scopus:0028863055
ISSN
1758-535X
language
English
LU publication?
yes
id
d76e5cf0-5781-4ca6-8e37-be68d381fa89 (old id 1109532)
date added to LUP
2008-07-28 16:32:56
date last changed
2017-08-06 04:32:53
@article{d76e5cf0-5781-4ca6-8e37-be68d381fa89,
  abstract     = {To assess the age-related loss of muscle mass and to determine the mechanisms behind this aging atrophy, the muscle structure and fiber type composition have been estimated, using invasive and noninvasive techniques. Limb muscles from older men and women are 25-35% smaller and have significantly more fat and connective tissue than limb muscles from younger individuals. Comparisons of muscle biopsies from younger and older individuals reveal that type 2 (fast-twitch) fibers are smaller in the old, while the size of type 1 (slow-twitch) fibers is much less affected. Studies of whole muscle cross sections also show a significantly smaller number of muscle fibers, a significantly lower relative type 2 fiber area, and a significant increase in fiber type grouping with increasing age. These results indicate a gradual decrease in size/volume with advancing age, accompanied by a replacement by fat and connective tissue. This aging atrophy seems to be due to a reduction in both number and size of muscle fibers, mainly of type 2, and is to some extent caused by a slowly progressive neurogenic process.},
  author       = {Lexell, Jan},
  issn         = {1758-535X},
  language     = {eng},
  pages        = {11--16},
  publisher    = {Gerontologial Society of America},
  series       = {Journals of Gerontology. Series A: Biological Sciences & Medical Sciences},
  title        = {Human aging, muscle mass, and fiber type composition},
  volume       = {50},
  year         = {1995},
}