When people over 60 walked on smooth, rounded cobblestones for just a half-hour a day over four months, they significantly lowered their blood pressure and improved their balance, a study showed.
Behavioral researchers from the Oregon Research Institute investigated the health effects of cobblestones after observing people exercising and walking back and forth over traditional stone paths in China.
"We noticed in several cities we visited that people were walking on cobblestone paths, and people were standing on them, and sometimes dancing on them, doing weight-shifting," said John Fisher, who led the study at the institute in Eugene.
"We thought if we could scientifically measure it, we could see if there were health benefits," he said.
The results surprised Fisher and his fellow researchers, who expected to see some general improvement in health but also saw blood pressure drop measurably among the volunteers during the 16-week study.
"It's very provocative," said Dr. David Ellison, the chief hypertension expert at Oregon Health & Science University in Portland.
"If they had done it over two years and lost 10 pounds I might be less surprised," Ellison said. "To do it that quickly - it's certainly dramatic."
The researchers in Eugene simulated the rounded, river rock cobblestones with a specially designed mat that was 6 feet long and 1 1/2 feet wide. Some of the test subjects walked in their bare feet, others wore socks.
They were compared with a control group who simply walked for an hour, three times per week. The results were published recently in the Journal of the American Geriatrics Society.
Nearly all the 108 volunteers in the study said they felt better after the exercise. But only the half who walked the cobblestones showed significant improvement in balance, measures of mobility and blood pressure, Fisher said.
Although cobblestone-walking is rooted in centuries of Chinese tradition, no controlled scientific studies had been done to evaluate its potential benefits and effectiveness until recently, Fisher noted.
Fay Horak, an Oregon Health & Science University neurophysiologist who specializes in balance, said the study is evidence that finding ways to maintain mobility and balance can delay and even prevent the effects of aging.
"I'm not surprised that working on balance improved balance," Horak said. "There's a lot of evidence that shows no matter who you are, it improves if you challenge it."
The body relies on two complex methods to maintain balance - the vestibular system in the inner ear and the somatosensory system that connects skin and muscles, Horak said.
Normally, people depend on the somatosensory system for about 70 percent of their balance control, and 30 percent on the inner ear.
But when the surface is uneven or unstable, the body switches reliance to the vestibular system and relies on it for about 70 percent of balance control, Horak said.
"It could be very helpful for people who are older because it's common as we age to lose receptors in the vestibular system," she said. "But by challenging people with an unstable surface, they use the remaining vestibular system and probably improve its function."
Ellison, the hypertension expert, said he would like to see a larger study to compare results but called the initial findings were promising.
"It certainly suggests there is something real about the cobblestones," Ellison said.
By William McCall