It sounds like a crazy way to improve your health—spend some time on a platform that vibrates at about the same frequency as the lowest string on a double bass. But recent research indicates that the procedure, known as whole-body vibration, may be helpful in illnesses from cerebral palsy to chronic obstructive pulmonary disease. Now, a new study of obese mice reveals that whole-body vibration provides similar metabolic benefits as walking on a treadmill, suggesting it may be useful for treating obesity and type II diabetes.
“I think it’s very promising,” says exercise physiologist Lee Brown of the California State University in Fullerton, who wasn’t connected to the study. Although the effects are small, he says, researchers should follow-up to determine whether they can duplicate them in humans.
Plenty of gyms feature whole-body vibration machines, and many athletes swear the activity improves their performance. The jiggling does seem to spur muscles to work harder, possibly triggering some of the same effects as exercise. But researchers still don’t know how the two compare, especially when it comes to people who are ill. So biomedical engineer Meghan McGee-Lawrence of the Medical College of Georgia in Augusta and colleagues decided to perform a head-to-head comparison of exercise and whole-body vibration.
The researchers tested mutant mice resistant to the appetite-controlling hormone leptin, resulting in obesity and diabetes. McGee-Lawrence and colleagues divided their animals into three groups. One group lived in cages on a platform that shook gently for 20 minutes each day, subjecting the animals to whole-body vibration. The second group scurried on a treadmill for 45 minutes per day, whereas animals in the control group could laze about to their hearts’ content.
After 12 weeks, the researchers found that exercise and whole-body vibration provided comparable health benefits. All three groups of mice gained weight during the study, but those in the exercising and shaken groups put on slightly less than the indolent rodents. They also had less fat and thicker leg muscles.
What’s more, mice in the two “active” groups showed signs of a healthier metabolism. People who are obese often have abnormally high levels of insulin but are resistant to its effects. Whole-body vibration and exercise reduced insulin levels by similar amounts in the mice and increased their responsiveness to the hormone, the scientists report online today in Endocrinology. And the team detected another positive effect. In patients who are obese or have type II diabetes, fat often accumulates in the liver, sometimes leading to organ malfunction and even death. But the mice that worked out on the treadmill or lived in the vibrating cages harbored about one-third as much fat in the liver as did the control rodents.
One area in which the shaking didn’t seem to help was skeletal health. Putting the skeleton under stress typically stimulates bones to reinforce themselves. But whole-body vibration didn’t strengthen the animals’ bones or increase their bone density. “Overall, the mice had poor skeletal health, and the interventions we tried did not reverse that,” says McGee-Lawrence. She notes, however, that the researchers did detect increased levels of osteocalcin, a hormone that indicates bone formation. That could mean that a longer study might uncover skeletal benefits that hadn’t appeared after only 12 weeks, she says.
But couch potatoes might not want to launch into a La-Z-Boy workout routine just yet. Whole-body vibration doesn’t provide the cardiovascular or respiratory benefits of physical activity, Brown notes, and “it’s not going to replace exercise.” McGee-Lawrence agrees, but adds that it could be an option for the many people who can’t work out because of time limitations or poor health. “The fact that whole-body vibration might be an alternative is pretty exciting,” McGee-Lawrence says. The next step, she says, is adapting the shaking regimen for human patients.