Build a Stronger Skeleton
To have sturdy, healthy bones, you gotta beat 'em up.
Train Smart continued...
Women who overdo it may develop a condition called amenorrhea,
which is triggered when overall body fat drops below 15%-17%. This is basically
exercise-induced menopause. An amenorrheic woman stops menstruating and her
estrogen levels take a dive. With low estrogen levels, bone loss speeds up,
just like it does in post-menopausal women. Many female athletes, DiNubile
says, are pleased with their lean, cover-girl bodies, "Yet they're not
healthy. They've got disease.
"You need to train smart," he says. You should maintain
a healthy weight -- not too plump, but not too hard -- and allow your bone
enough time between workouts to heal and grow.
Clinton Rubin, PhD, a scientist at the State University of New
York in Stony Brook, thinks he may have found another way to build bone:
vibration. His experiments have shown that gentle, high-frequency vibrations
greatly increase bone growth. In a recent study, he had sheep stand on a
vibrating platform for 20 minutes, five days a week, over the course of one
year. The density and volume of their leg bones increased by more than 30%.
Rubin's research is funded by NASA's National Space Biomedical
Research Institute. NASA is interested because bone loss is a bane to
astronauts. According to Rubin, we lose about 2% of our bone per decade here on
Earth. Astronauts lose about 2% of their bone per month in space. Under
no stress from gravity, bone dissolves. "It's doing exactly what it thinks
it should do," Rubin says. That is, a weightless body doesn't really need
bones. It's responding to the environment.
At present, both American astronauts and Russian cosmonauts try
to fight bone loss with intense exercise programs. They spend four hours a day
doing high-impact, bone-building workouts, Rubin says. Still, the bone loss
Rubin thinks a healthy skeleton depends on the body's natural
vibrations, in addition to the strain placed on bone by exercise. Even when
sitting upright or standing still, your muscles are working to maintain your
posture. The muscles vibrate at 10-50 hertz, and Rubin thinks these subtle
vibrations stimulate bone growth. In space, a human body doesn't strain against
gravity to hold its posture. The muscles are relaxed, and bone is not
constantly subjected to muscular vibrations.
If Rubin is right, a vibrating platform could remove one more
obstacle to sending astronauts on a mission to Mars. What's more, vibration
might become a first-line treatment for osteoporosis, as well as a way to
prevent it. Better treatments for osteoporosis are sorely needed. DiNubile says
he worries about what will happen when today's young women go through "the
change" some 40 years from now. "They're not even close on calcium
intake," he says. What's more, teens tend be sedentary and guzzle massive
quantities of soft drinks. All things considered, it looks like an epidemic of
shattered hips may plague us mid-century.