 |
|
Rest vs. rust |
|
| Rest may be just what the doctor orders for an attack of
muscle breakdown. But while rest helps the damaged muscle cells recover, inactivity can weaken the healthy muscle cells. That makes pacing a comeback from muscle injury very tricky, says Christine Kasper, Ph.D., R.N., director of doctoral programs at Johns Hopkins University. “We used to believe that exercise would not harm muscle that had atrophied from lack of use. But we now know that muscle weakened from disuse can be seriously damaged when people are pushed beyond the point of pain.” Kasper first noticed this problem 20 years ago when she studied a group of people who had been forced to rest for four weeks before starting a moderate walking program. To her surprise, microscopic examination of muscle revealed that the exertion was destroying muscle cells, not rebuilding them. “After a month of enforced rest, even moderate walking proved too much,” concludes Kasper. Why does inactivity weaken muscle? Just as your body revs up when you work out, so it gears down when you slack off, says Kasper. Because your muscles are using less oxygen, your body cuts back on the production of oxygen-carrying red blood cells. Blood volume drops and heart rate speeds up. Eventually, the number of capillaries in the muscle decreases, lung capacity drops and muscle cells begin to atrophy or shrink. With as little as four to eight hours of inactivity, the effects of down-gearing can be observed. In that state, muscles simply can’t perform up to snuff, says Kasper. “Trying to exercise as usual with weakened muscles is like trying to hold up a heavy weight with a rope that’s too thin,” she says. “Just like the fibers in that rope, muscles that are over-stressed will begin to rip and tear.” How to balance rest and exercise while injured muscles recover? Kasper suggests going slow and listening to your body. “If you’re short of breath or have pain, stop and rest,” she says. She also advises gentle stretching before exercise. Stretching improves flexibility, which in turn helps to protect the muscle from further injury. |
|
|
|||
|
|||
|
|||
| Related
links: Exercise-induced increase in serum creatine kinase is modified by subsequent bed rest  Abstract of a 1997 study in Finland. Heat helps muscle in immobilized limbs University of Florida study that found atrophy was 32% lower in inactive rats treated with heat therapy. Stretching: A key to avoiding athletic injuries A new resource from Mayo Clinic. Type II muscle fiber atrophy Microscopic views of three kinds of atrophy, including disuse atrophy. Muscle
atrophy Rebuilding
wasted muscles |
|
|
|
|
|||
To read patient comments about balancing rest and exercise, visit 
You can do a disservice to yourself when you stretch past the
point of pain. We always say you should never hold a painful
stretch. You should back off just to where it's not painful,
and that's what you want to hold during the duration of the
stretch. 
