Exercise notes

Several health-related stories caught my eye today, so before I start studying for tomorrow's anatomy & physiology exam, here they are.

THE NATIONAL OSTEOPOROSIS FOUNDATION released new guidelines today. They include:

• For adults over 50, 1,200 milligrams a day of calcium and 800 to 1,000 international units a day of Vitamin D, more D than the government recommends.
• Do regular weight-bearing and muscle-strengthening exercise. (More on this below.)
• Recommend that all men over 70 get bone-mineral density X-ray tests (just as already been recommended for women over 65). Earlier tests are recommended for those individuals with additional risk factors.
• Treat postmenopausal women and men 50 and older who have thinning bones, but not osteoporosis yet, if they have at least a 20 percent risk of any major fracture in the next decade, or at least a 3 percent risk of a hip fracture.
• Check for osteoporosis risk factors in postmenopausal women and men 50 and over, to see who needs a bone test before their senior years.
• A bone test for anyone who has any type of fracture after age 50, or who has conditions associated with bone loss, such as rheumatoid arthritis.

With regard to weight-bearing exercise as mentioned above, here's an article with some specifics on what does and doesn't help maintain bone mass. Both weight training and aerobics are helpful, though the latter has a caveat.

While aerobic activity of all kinds is good for general health, some forms don't help your bones. Those that don't include swimming, cycling, and... StairMasters and StairClimbers at the gym (I forced myself to get on the treadmill instead today).

Bone mass peaks in our 20s. After that it's a long slow decline... we can let it proceed at full speed or slow it with a combination of healthy food choices, adequate exposure to sunshine, and exercise (see the National Osteoporosis Foundation article mentioned above).

NEXT UP... FAT CELLS. When I was a freshman in college, I got the idea from my P.E. class that if I starved myself for six months, I could kill off some of my fat cells. I gave it a try with pretty bad results... during a regular check-up with my doctor, he thought I was become diabetic. He told me to start eating regularly again, and sure enough, I was soon back to normal.

In any case, the latest research indicates that once we enter our 20s, the number of fat cells in our body is pretty much set for the rest of our lives. While it may go up, it's not going to go down, even after weight-loss surgery.

So if you've got kids under 20, try to keep them from becoming overweight, and if they already are, work with your doctor to address the problem.

And if you're over 20 and overweight, what you can do is reduce the amount of fat stored in each fat cell. There's no magic formula: it's eat less and move more.

AND THAT'S GOOD ADVICE for most of us.

"New Jobs for Ancient Chaperones" in the July issue of Scientific American today examines the roles of so-called heat-shock proteins (HSPs) in the human body. Since they were originally discovered in an experiment that exposed flies to high temperatures, HSPs have been found in just about every living organism on earth. Their function is to keep essential cellular processes running, especially when the cell is exposed to stress. While heat was the original type of stress found to activate HSPs, researchers have since learned that other forms of stress do so as well: low oxygen conditions, cancer, infectious disease, etc.

There's some evidence that exercise puts just enough healthy stress on the body's cells--higher body temperatures, oxygen debt, and other metabolic changes--to engage the HSP mechanisms and boost our overall immune response.

So get moving. :-)