In the 1940s, a podiatrist named Samuel Shulman examined the feet of a few thousand Chinese and Indians who never wore shoes. Their feet were in much better shape than the feet of people who wear shoes regularly.
The resulting complete absence of onychocryptosis [ingrown toenail] should serve to prove that proper nail care plus nonrestrictive footgear are all that is necessary to prevent the condition even in the presence of congenital nail malformations that are considered predisposing factors. . . . One hundred and eighteen of those interviewed were rickshaw coolies. Because these men spend very long hours each day on cobblestone or other hard roads pulling their passengers at a run it was of particular interest to survey them. If anything, their feet were more perfect than the others. All of them, however, gave a history of much pain and swelling of the foot and ankle during the first few days of work as a rickshaw puller. But after a rest of two days or a week’s more work on their feet, the pain and swelling passed away and never returned again.
Chinese parks often have cobblestone-like paths that are extremely painful to walk on barefoot (for me) but that others (usually old Chinese people) walk on barefoot for health. I was surprised how clearly the pain went away day by day of exposure. A 2005 study showed that four months of walking on cobblestone mats reduced blood pressure and improved balance compared to a group that walked the same amount normally:
Participants [average age about 80 years old] were randomized to a cobblestone mat walking condition (n=54) or regular walking comparison condition (n=54) and participated in 60-minute group exercise sessions three times per week for 16 consecutive weeks.
Measurements: Primary endpoint measures were balance (functional reach, static standing), physical performance (chair stands, 50-foot walk, Up and Go), and blood pressure (systolic, diastolic). . . .
Results: At the 16-week posttest, differences between the two exercise groups were found for balance measures (P=.01), chair stands (P<.001), 50-foot walk (P=.01), and blood pressure (P=.01).
Some of the cobblestone walkers walked barefoot, some wore socks. A hypertension expert, apparently not understanding statistics, said he wanted a larger study. I agree with him when he says that the speed of the improvement is what’s most impressive.
Because our ancient ancestors no doubt went barefoot and walked on irregular surfaces, both sets of results — the foot survey and the cobblestone experiment — support conventional paleo theorizing.
I have a cobblestone mat. I tried to walk on it. It was so painful I couldn’t get past the initial difficulty. Maybe I will try again.