Last spring, I made the mistake of wearing flip-flops on a couple of long walks with my dog. “What does it matter?” I thought. “It’s just an hour walk.” But after doing this a couple of times, I noticed that my knees were sore and my ankles were stiff.

Fortunately, I was bright enough to make the connection between the flip-flops and my discomfort, so I tossed the flip-flops. After switching to a good pair of walking shoes, my joints were no longer sore.

Every summer, thousands of folks slip out of their regular walking shoes and start piling on the miles in flip-flops. As a result, many end up having to visit a doctor.

I asked Dr. Michael Sommers, a chiropractor in Roncasvilles, Toronto, to explain why this innocent-looking footwear can lead to such a dramatic onset of pain.

According to Dr. Sommers, “There is nothing remotely healthy about wearing flip-flops, especially during long walks. They provide little or no support to the ankle and only minimal shock absorption during weight-bearing activity – leading to wear and tear in the joint surfaces of the ankle, knee, and spine. Flip-flops were designed for the beach. That’s really only where they should be worn.”

A study presented at the American College of Sports Medicine found: “When people walk in flip-flops, they alter their gait, which can result in problems and pain from the foot up into the hips and lower back. When subjects wore flip-flops, they took shorter steps and their heels hit the ground with less vertical force than when they wore athletic shoes.”

The researchers concluded that you should wear flip-flops only for a short period of time. So chuck your thong sandals and replace them with walking shoes. Your feet will thank you.

[Ed. Note: Sometimes, super-simple lifestyle changes can have a major effect on your health. Learn how to start feeling better and getting healthier right here.

If you’re looking to lose weight and get fit, try fitness expert Craig Ballantyne’s Turbulence Training Program.]

Craig Ballantyne

Craig Ballantyne is the author of The Perfect Day Formula: How to Own the Day and Control Your Life. Craig has been a contributor to Men's Health magazine for over 17 years. Today he teaches his gift high-performing entrepreneurs how to squeeze more out of their days, increase their income, and make more quality time for their families in his Perfect Life Workshop and Work-Life Mastery programs. Craig used his own advice to overcome crippling anxiety attacks in 2006, and he'll teach you his 5 Pillars of Success so you can increase your income, decrease your work time, and live the life of your dreams. Learn more about Craig at craigballantyne.com