Q. I've heard that vibration therapy can help to improve bone density. Can you tell me more about it?
A. Our bones are in constant flux, as old bone is broken down and new bone is created. If old bone is broken down faster than new bone is created, low bone density and eventually osteoporosis develops.
After menopause, women are more prone than men to develop osteoporosis. One reason is that their natural estrogen levels drop, and estrogen helps preserve bones. Women are advised to stimulate their bones through physical activity, particularly weight-bearing and resistance exercise. That's because stress placed on the bones through activities such as running and weightlifting makes bones denser and stronger. Many drugs are also used to prevent and treat osteoporosis.
But for some women, exercise and medication may not be enough. As they age, health problems may limit women's ability to get bone-enhancing exercise. And many women can't tolerate or prefer not to take osteoporosis medications.
That's where vibration therapy might come in.
Low-intensity vibration devices gently stimulate muscle and bone. (Don't confuse them with high-intensity, whole-body vibration, which is used mainly for exercise training.)
In low-intensity vibration therapy, you stand on a platform that resembles a bathroom scale. The device oscillates up and down a barely noticeable amount. Both the size and speed of the vibration are set to match the natural stimulation that occurs as your muscles relax and contract to maintain your posture.
How vibration therapy promotes bone density isn't well understood, but researchers have several possible explanations. Vibration enhances circulation to muscle and bone, boosting the supply of nutrients to these tissues.
Exposure to low-intensity vibration has been used to prevent bone loss in people who are unable to perform any weight-bearing exercise whatsoever -- patients with spinal cord injuries, for example.
But does it work for age-related osteoporosis? We don't know yet. For now, it's not clear who is most likely to benefit from low-intensity vibration, what an effective dose is, and how long it should be done.
There are also safety concerns. The very people who are most likely to benefit from this therapy -- frail older people with osteoporosis who are at risk of falling -- are also the most likely to hurt themselves trying.
So I can't recommend vibration therapy to you, based on current evidence. Fortunately, today there are many effective therapies to protect against losing bone density and developing osteoporosis, most of them developed in the past 30 years. Many different types of medicines are effective: calcium and vitamin D, bisphosphonates, hormone therapy, selective estrogen receptor agonists, parathyroid hormone, calcitonin and others. Not all of them are right for everyone.
If you haven't already, talk to your doctor about whether you need to take any treatment right now and, if so, what your options are. I'll keep my eyes open about vibration therapy, and if it looks like it might be worth considering, I'll write a column about it.
• Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com.