Updated on 4/4/2005
We've all seen those infomercials touting ab stimulators, devices that are supposed to tone and strengthen your abdominal muscles so that before you know it, you'll have washboard abs without the effort and inconvenience of months or years of crunches. Some of the ads for the stimulators actually claim that they'll work while you loll on the couch watching TV. Sound too good to be true? For the most part, it is.
These products are based on technology long used in physical therapy to reduce muscle atrophy in bed-ridden patients. The small jolt of electricity that the devices deliver, usually through electrodes affixed to the skin, are enough to make a muscle contract. As a result, weakened muscles are "exercised" and become stronger. But what works to strengthen weak muscles so that they don't atrophy doesn't necessarily strengthen and tone normal muscles. No independent scientific studies have demonstrated that the stimulation provided by the ab devices work for normal healthy people.
However, the FDA did approve marketing of one of these devices after the manufacturer submitted data showing that women who used the product increased muscle strength by 12 percent in eight weeks compared to no improvement in control subjects who did nothing. According to the manufacturer, you have to continue use the device two to three times a week to maintain results. There was no comparison study to measure improvements in muscle strength after completing traditional gym exercises for eight weeks.
The FDA regulates these products because they're offshoots of the medical devices used for physical therapy. Approved stimulators must demonstrate that they're safe and effective. In the past, the FDA has warned against the non-medical use of the stimulators because they can cause burns and skin irritation and even breathing problems or heart arrhythmia if placed improperly. For the time being, unapproved ab stimulators will remain on the market - the FDA is giving manufacturers time to comply with approval requirements. However, without approval there's no assurance that a device is safe, much less that it will work.
By the way, you should know that some of the other heavily advertised abdominal exercisers - the non-electronic type - don't work any better than the standard abdominal crunch.
If you want to flatten your abs or trim your waist, I suggest you do it the old fashioned way via a combination of diet and exercise. You'll save your money and get better results - and a great deal of personal satisfaction.
Andrew Weil, M.D.