When we wear high heels, we look taller and leaner and our derrieres stick out oh-so-becomingly. But: Even heels of a relatively moderate height can permanently damage muscles, tendons and joints, according to two recent studies. 

In the first study, European researchers used ultrasound and MRI to analyze the leg anatomy of women who had worn shoes with a minimum heel height of five centimeters (just under two inches) at least five days per week for two or more years. Compared with women who did not regularly wear heels, the high-heelers had calf muscle fibers that were 13% shorter, on average… Achilles tendons (which attach calf muscles to heel bones) that were thicker and stiffer… and reduced range of motion in the ankles. This explains why long-term heel-wearers often feel pain when they wear flat shoes or sneakers.

The second study, from Iowa State University, assessed the forces acting on the knee joint and the heel strike-induced shock wave that moves up the body when a woman walks in flats… in two-inch heels… or in 3.5-inch high heels. Results: The higher the heel, the greater the compression on the inside of the knee — a factor that could contribute to joint degeneration and knee osteoarthritis. Researchers also found that high heels altered posture by changing the position of the joints at the ankle, knee and hip, which could lead to low-back strain.

Our expert’s views: High heels are OK to wear occasionally, we heard from podiatric surgeon Johanna Youner, DPM, of New York Downtown Hospital, who was not affiliated with the studies. Her advice: Reserve high heels just for special events, or at least avoid wearing them on consecutive days or for more than two hours on any given day, so calf muscles have a chance to elongate. Take off your high heels periodically during the day and stretch your calf muscles… stretch again at the end of the day. Limit the distance you walk in heels — for instance, do not wear them to walk down city streets or trek through the mall.