Why Not Use Heel Lifts?

There are issues which can affect you if you choose to put heel lifts in your shoes. These are seldom severe, and the therapeutic value of the lift will generally far outweigh the issues it may cause in most cases, but be aware that nothing comes without a cost.

Placing heel lifts in your shoes creates secondary effects similar to the wearing of any high-heeled shoes; cowboy boots, ladies' high-heels, and many types of fashion shoes cause similar adaptations in the wearer's stride, gait, foot, and lower leg, and can create foot and ankle problems if the added height is excessive or the shoe is not well-engineered for you.

Potential Long-Term Side-Effects of Using Heel Lifts:

• If a lift raises only the heel, then there can be "bridging" between the heel and the ball of the foot. This lack of mid-foot support can cause arch problems, particularly if a soft lift is constantly pushing the foot upward against the tongue of the shoe.
  This can be avoided by using a lift which is long enough to support the mid-foot almost all the way forward to the metatarsal area, and which does not compress when walking. A well-designed heel lift should effectively tilt the foot bed or insole forward as if it were part of the last of the shoe, rather than leaving the mid-foot unsupported. In heel lifts, longer is better.
• The addition of a lift in the heel of a shoe causes the foot to be resting on a slope downward toward the toes. This can cause fore-and-aft slippage in the shoe when walking, and can result in calluses under the metatarsal or ball of the foot or the large toe. This effect is very dependent on the person's gait and stride, and is seldom serious unless the calluses become corns, but can be annoying.
  Such calluses can be avoided or reduced by the use of cushioned or silk socks, to reduce skin friction while walking.
• Achilles' tendon issues; since a heel lift raises the foot within the shoe, it can cause inflammation of the tendon due to the pressure and rubbing of the narrower top part of the heel cup or heel counter pressing against the tendon, and, can cause shortening of the tendon and hamstrings due to the reduced angle at the ankle from the steeper slope on which the foot rests. Tendons which are not stretched regularly tend to shorten. The reduction in tension on the Achilles' caused by use of a heel lift can be beneficial, if the therapeutic goal is to allow for tendon healing.
  Achilles' tendon shortening can be counteracted by regular stretching exercises which stretch the calf and bend the foot and ankle gently upward under light tension.
• All molded foam in-shoe lifts are soft enough to create appreciable vertical motion in the shoe when walking or running, and the increased rubbing of the heel can cause calluses and blisters, inflammation of the Achiles' tendon, and excessive wear on socks and shoes. Also, the constant pressure of a soft shoe lift pressing upward against the foot has the potential to cause or aggravate mid-foot and arch problems.
  Unless you are trying to cushion or reduce impact on inflamed pressure points such as plantar warts or heel spurs, the use of compressible gel or foam heel lifts should be avoided.
• Badly-designed height inserts are also very uncomfortable for your foot; placing a badly-shaped lump of foam in your shoes will not be comfortable for walking. Period. For a review of one such product, HeightShoeReview.com offer their impressions. Don't waste your money on these, they are unusable.

A Short-Term Issue

In the short term, the most acute problem likely to come from using shoe lifts is associated with "height-enhancing" heel lifts which place more than 1/2" inside common types of shoes; if the height inserted is more than 1/2", the heel will not be firmly held in place by the shoe, and the wearer will tend to walk out of the shoe, and be prone to sprain or break an ankle after losing control when the ankle rolls to the side with the foot tucked under. Shoe inserts which add more than 1/2" of height should be avoided, due to this risk. 

A much safer alternative for adding more than 1/2" of apparent height is to use one of the many shoes which are specifically designed for the purpose, which raise the full foot rather than just the heel, and which have heel-cup and side support designed to keep the heel in place while adding height.

Only you can determine whether possible issues resulting from the use of therapeutic or height-enhancing shoes or lifts are acceptable for you and your body, but the use of in-shoe heel inserts is probably best prescribed and monitored by a health-care professional such as a Podiatrist, Physical Therapist, Chiropractor, or Orthotist.