# What causes older people to become slow and inflexible exactly, and is it avoidable **URL:** \ **Category:** Factual Questions\ **Created:** [July 25, 2004, 2:19pm UTC](https://boards.straightdope.com/t/what-causes-older-people-to-become-slow-and-inflexible-exactly-and-is-it-avoidable/256801 "2004-07-25T14:19:48Z")\ **Posts on this page:** 12\ **Page:** 2
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [July 26, 2004, 12:54am UTC](https://boards.straightdope.com/t/what-causes-older-people-to-become-slow-and-inflexible-exactly-and-is-it-avoidable/256801/21 "2004-07-26T00:54:15Z")
> [@KarlGauss](#): > > **dtilque** : Sorry, didn’t see your post. It came while I was composing mine. That’s OK. You had a lot of technical detail that I didn’t know. Thanks. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [July 26, 2004, 1:27am UTC](https://boards.straightdope.com/t/what-causes-older-people-to-become-slow-and-inflexible-exactly-and-is-it-avoidable/256801/22 "2004-07-26T01:27:41Z")
Since it appears that reactive oxidation plays a large role in aging, wouldn’t antioxidants be a help in retarding aging? In addition to which, exercise increases the numbers of free radicals, requiring additional antioxidants. ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [July 26, 2004, 1:41am UTC](https://boards.straightdope.com/t/what-causes-older-people-to-become-slow-and-inflexible-exactly-and-is-it-avoidable/256801/23 "2004-07-26T01:41:07Z")
> [@barbitu8](#): > > Since it appears that reactive oxidation plays a large role in aging, wouldn’t antioxidants be a help in retarding aging? In addition to which, exercise increases the numbers of free radicals, requiring additional antioxidants. As you can imagine, this is a huge and growing area in clinical and experimental medicine. [Here is one tantalizing study](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=14594788). And, [here is a rather optimistic review](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12882341). In truth, most of the randomized controlled trials have been negative or of marginal significance. Many of the ‘postiive’ studies have used “surrogate markers” (eg. theoretically favourable biochemical changes) rather than outcomes of real relevance (eg. death or heart attack). So, the usual cliche applies: More research is needed. ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [July 26, 2004, 1:58am UTC](https://boards.straightdope.com/t/what-causes-older-people-to-become-slow-and-inflexible-exactly-and-is-it-avoidable/256801/24 "2004-07-26T01:58:53Z")
Every living thing ages and undergoes changes, for the worse, in the process. During the depression a Bernard McFadden published a magazine regarding exercise and health. Bernard was of the opinion, and promoted, exercise as the way to live to a ripe old age in excellent. As I recall he didn’t put out his magazine one month and never heard of him again except n retrospect. ---
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [July 26, 2004, 2:07am UTC](https://boards.straightdope.com/t/what-causes-older-people-to-become-slow-and-inflexible-exactly-and-is-it-avoidable/256801/25 "2004-07-26T02:07:19Z")
> [@barbitu8](#): > > When I hijacked this thread and asked that question, I did not recall reading about it, but after I posted and after I wrote about fast-twitch muscles, my aging and feeble mind recalled reading an article a few years ago on exactly this topic. Actual studies and biopsies were done on muscles of runners, and it was concluded that the fast-twitch muscles do degenerate in time, becoming more similar to slow-twitch muscles. Now is that because of age, or adaptation to the demands of running? ---
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [July 26, 2004, 2:46am UTC](https://boards.straightdope.com/t/what-causes-older-people-to-become-slow-and-inflexible-exactly-and-is-it-avoidable/256801/26 "2004-07-26T02:46:59Z")
btw, the time to peak contraction for slow-twitch fibers is not that much less than that for fast-twitch. I want to say that we’re looking at 70 ms rather than 40 ms–I don’t know if those are the exact right numbers, but it’s pretty close to the order of magnitude. I don’t think that’s enough of a difference to make you really slow\*. Inflexibility can make you slow, no doubt, but I’d also be curious about the effects of peripheral and central nervous system degeneration. \*And I actually recall reading about a study that found that individual fibers can have multiple fiber types at different points, cause they’re long. So that’s probably not it. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [July 26, 2004, 8:45pm UTC](https://boards.straightdope.com/t/what-causes-older-people-to-become-slow-and-inflexible-exactly-and-is-it-avoidable/256801/27 "2004-07-26T20:45:55Z")
The degradation is due to age. Although you say that it doesn’t make much difference, it surely does. There are two types of fast-twitch, type IIa and type IIb, type 1 being slow twitch. Only IIa is really fast twitch. The difference you note is about twice as fast, which is really quite a bit. The article I remember reading (but I don’t remember in what periodical - probably _Peak Performance_) did not state that the fast twitch became slow twitch, but the muscle fibers and structure degraded, so that it became more like slow twitch. It was the conclusion of that article that this is the reason we slow down as we age. However, the decrease of VO2 obviously plays a part. Sprinters may have as much as 80% fast twitch; whereas, endurance runners may have as much as 80% slow twitch. It is a known fact that even tho we slow down as we age, our ability to perform in endurance events is not noticeably diminished. The real question is why these changes occur, as they are unavoidable. And the answer for this probably resides in the posts provided by **KarlGauss** and **dtilque**. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [July 26, 2004, 9:02pm UTC](https://boards.straightdope.com/t/what-causes-older-people-to-become-slow-and-inflexible-exactly-and-is-it-avoidable/256801/28 "2004-07-26T21:02:53Z")
I checked my library and the only book I have now which is germane is _Cellular Physiology of Nerve and Muscle_, Gary G. Matthews (1998). On page 197,he states: “The time delay between the occurrence of the muscle fiber action potential and the peak of the resulting tension is not constant across all muscle fibers. The delay to peak tension can be as little as 10 or as many as 200 msec… Samples of isometric contractions in fast and slow fibers are shown in Figure 10-5.” That figure compares the speed of development of isometric tension in fast and slow muscle fibers. Fast fibers reach their peak just shy of 50 msec after activation. Slow fibers reach their peak just shy of 150 msec after activation, making fast twitch fibers three times faster, according to the math I learned when I went to school. ---
**Author:** ![easy\_e](https://avatars.discourse-cdn.com/v4/letter/e/eb8c5e/32.png) [@easy\_e](https://boards.straightdope.com/u/easy_e)\ **Post date:** [July 28, 2004, 3:03am UTC](https://boards.straightdope.com/t/what-causes-older-people-to-become-slow-and-inflexible-exactly-and-is-it-avoidable/256801/29 "2004-07-28T03:03:38Z")
[slight hijack] **KarlGauss** – A few summers ago I worked in a lab that was trying to (eventually) make bioartificial blood vessels. In other words, made in a lab but of living cells and matrix. They were really weak, and one of the ways to increase their strength was to add sugars (I believe they used glucose) to cross link the collagen “scaffolding”. They got the idea from the hardening of arteries in diabetics. ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [July 28, 2004, 3:09am UTC](https://boards.straightdope.com/t/what-causes-older-people-to-become-slow-and-inflexible-exactly-and-is-it-avoidable/256801/30 "2004-07-28T03:09:11Z")
Isn’t that something! Very interesting, indeed. Thanks, I’d never have known that. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [July 29, 2004, 1:12am UTC](https://boards.straightdope.com/t/what-causes-older-people-to-become-slow-and-inflexible-exactly-and-is-it-avoidable/256801/31 "2004-07-29T01:12:11Z")
I just received the July 10, 2004 issue of _Science News_ (along with the July 17 - better late than never). I’m going to quote from sections of an article titled “Dying Before Their Time.” > [@](#): > > …Remaining within the mitochondrion itself, however, is a small loop of DNA harboring 13 assorted genes. It is this DNA that some researchers suspect may hold the keys to aging. Because mtDNA isn’t sequestered in the nucleus, it’s exposed to potentially damaging molecules floating around the cell’s cytoplasm. What’s more, mtDNA doesn’t have the benefit of the repair enzyms available to genes in a nucleus. > > Also, the very work that mitochondria do may damage their DNA. The act of creating ATP spawns toxic by-products called free radicals that can rip nearby molecules to shreds. That, conceivably, could underlie various aspects of aging. > > “All cells depend on mitochondria for energy, and if the mitochondria begin to fail, then you would expect to see a general slowing of activity throughout all the cells of the body,” says [David] Samuels. “And that description fits with aging.” [snip] > > Those researchers [in the May \*Trends in Genetics]/i]] put the mitochondrial theory of aging to a direct test by creating mice with a defective gene for the enzyme that copies mtDNA. [snip] At birth, mice with this defective enzyme look and act healty. Five months into their lives, however, they already seem to be getting old. They start to lose hair and weight and to develop osteoporosis, which leads to a curvature of the spine. Their hearts enlarge, and the mice become anemic and infertile. All of the rodents in Larsson’s study were dead within 14 months; in contrast, a typical lab mouse lives 24 to 36 months. [snip] > > That said, the new study leaves many questions unanswered. For example, how does an increase in mtDNA mutations cause so many aging-related problems? One possibility is that key cells may die or fail to perform necessary duties as their mitochondria produce less ATP. Another is that deteriorating mitochondria may, as they struggle to make ATP, unleash a flood of extra free radicals that disrupt other cellular functions. ---
**Author:** ![tygerbryght](https://avatars.discourse-cdn.com/v4/letter/t/a9a28c/32.png) [@tygerbryght](https://boards.straightdope.com/u/tygerbryght)\ **Post date:** [July 30, 2004, 2:50am UTC](https://boards.straightdope.com/t/what-causes-older-people-to-become-slow-and-inflexible-exactly-and-is-it-avoidable/256801/32 "2004-07-30T02:50:47Z")
> [@barbitu8](#): > > I just received the July 10, 2004 issue of _Science News_ (along with the July 17 - better late than never). I’m going to quote from sections of an article titled “Dying Before Their Time.” There are some very interesting articles in the current (in your bookstore) Scientific American special edition _ **The Science of Staying Young** _. It includes several pertinent articles. I have been trying to figure out how to let people here know that there’s an article on atherosclerosis (artery blocking) that is amazingly clear and understandable. Unlike most of their Special Editions, this one does not have a “pull date” on it, so I don’t know how long it will be available. I do know that it has been mentioned in a couple of recent issues, so it’s been out for several months (I’m just slow getting it). [Previous page](https://boards.straightdope.com/t/what-causes-older-people-to-become-slow-and-inflexible-exactly-and-is-it-avoidable/256801.md?page=1)