With the VO 2 max test, you hop on a treadmill or stationary bike and give your maximum effort while wearing a mask that captures your every breath. By analyzing the amount of oxygen you consume, the test determines how efficiently your body extracts and uses oxygen from the air. This makes it the gold standard of fitness markers, as well as a strong indicator of your overall health. "Blood pressure, cholesterol -- those are what we call 'remote markers.' The best predictor of your longevity is going to be your fitness," says Walter Bortz, M.D., a longevity researcher at Stanford University.
Who needs it: Anyone who wants their blood to pump. If your score is under 18 ml/kg/min, talk to your doctor about increasing the intensity of your workouts.
Cost: $110 to $160. The test is available at physical therapy, rehab, or cardiopulmonary centers. Insurance providers won't cover it.
By definition, something "virtual" usually can't compare to the real thing. But with a virtual colonoscopy, you avoid the two downsides of a traditional colonoscopy -- sedation and the risk of a perforated colon -- while still benefiting from the one big upside: test results you can stake your life on. "Virtual colonoscopies have the same sensitivity for detecting large polyps, which are the precursor lesions of colon cancer," says Judy Yee, M.D., a professor of radiology at the University of California at San Francisco. Though the CT scanning technology of a virtual colonoscopy can miss some smaller polyps, a University of Wisconsin study found that these are usually benign anyway. And don't sweat the radiation; you'll receive about 5 to 8 millisieverts, an amount that isn't considered dangerous, says Dr. Yee.
Who needs it: People ages 50 and older, especially those on blood thinners, because an "oops" with a regular scope could cause dangerous internal bleeding. The exception: If your family has a history of colon cancer, you should be screened at least 10 years before the age your relative was when he or she was first diagnosed, Dr. Yee says. People who are overweight or inactive, drink or smoke heavily, or have an inflammatory bowel disease should also consider early screening.
Cost: $500 to $1,000. Many health-care plans now recognize the effectiveness of virtual colonoscopies and increasingly cover them.
Tip: Cut back on calories and chemicals by avoiding the 20 unhealthiest drinks in America.
While it's not a test per se, putting your diet under the microscope could result in a leaner body and a longer life. "The benefits of meeting with a dietitian are accountability, moral support, and troubleshooting if your progress stalls," says Alan Aragon, M. S., the Men's Health Weight-Loss Coach. In a 2008 Kaiser Permanente study, diabetic patients who received nutritional counseling were nearly twice as likely to lose weight as those who had no guidance. To find a registered dietitian who can see beyond the food pyramid, Aragon recommends going to the American Dietetic Association's Web site (eatright.org)and clicking on "Find a Nutrition Professional." Then call the R.D. and ask how he or she stays up on the latest research, which should include reading journals such as the American Journal of Clinical Nutrition or the Journal of Applied Physiology.
Who needs it: Anyone who should lose weight or simply wants to know how they can eat to beat disease.
Cost: $40 to $75 a session. Your insurance company may reimburse you if you have a condition that can be improved with diet changes. Ask your doctor for a referral.
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