Another motivation to exercise - Exercise keeps BONE MARROW from becoming flabby.

[snagglepuss]

Source NYT

Article discusses a new reason why exercise for kids is especially important but the findings apply to all people.


snip


For those requiring additional reasons to show up at the running path or at the gym in the dreary heart of winter, science has come up with a compelling new motivation. Exercise can, it appears, keep your bone marrow from becoming too flabby.

snip

... the fate of marrow stem cells determines the strength and quality of the bone. If a stem cell becomes a fat cell, then the portion of the skeleton to which it might have migrated as a bone cell will be that littlest bit punier. In a study published late last year by researchers at the University of Southern California, the femurs of healthy adults, some in their 20s, others past age 55, were scanned with magnetic resonance imaging. The researchers found that, in both young and old, the amount of fat in the leg’s bone marrow was inversely related to the amount of bone. The more fat in the marrow, the less bone in the thigh.


snip

“Stem cells love to become fat cells,” Dr. Rubin said. “It’s discouragingly easy to nudge them in that direction.”

But... when stem cells were... exercised, they did not all become fat cells.


snip


Still, one lesson is indisputable. Don’t sit still more than you need to, Dr. Rubin said, and don’t let your children loll about either. “One of the concerns raised” by these experiments, she said, “is that if you make fat cells when you’re young, then you’ve lost any opportunity to have that particular cell be bone,” and the fat cell will remain just that, for life.





http://well.blogs.nytimes.com/2011/02/02/phys-ed-more-bone-and-less-fat-through-exercise/