Physical Training and Activity in People With Diabetic Peripheral Neuropathy: Paradigm Shift

Abstract

Diabetic peripheral neuropathy (DPN) occurs in more than 50% of people with diabetes and is an important risk factor for skin breakdown, amputation, and reduced physical mobility (ie, walking and stair climbing). Although many beneficial effects of exercise for people with diabetes have been well established, few studies have examined whether exercise provides comparable benefits to people with DPN. Until recently, DPN was considered to be a contraindication for walking or any weight-bearing exercise because of concerns about injuring a person's insensitive feet. These guidelines were recently adjusted, however, after research demonstrated that weight-bearing activities do not increase the risk of foot ulcers in people who have DPN but do not have severe foot deformity. Emerging research has revealed positive adaptations in response to overload stress in these people, including evidence for peripheral neuroplasticity in animal models and early clinical trials. This perspective article reviews the evidence for peripheral neuroplasticity in animal models and early clinical trials, as well as adaptations of the integumentary system and the musculoskeletal system in response to overload stress. These positive adaptations are proposed to promote improved function in people with DPN and to foster the paradigm shift to including weight-bearing exercise for people with DPN. This perspective article also provides specific assessment and treatment recommendations for this important, high-risk group.

Figure 1.

Tissue adaptation to physical stress. Reprinted with permission from Mueller MJ, Maluf KS. Tissue adaptation to physical stress: a proposed “physical stress theory” to guide physical therapist practice, education, and research. Phys Ther. 2002;82:383–403.

Figure 2.

Signaling events involved in diabetic peripheral neuropathy pathogenesis. Initiating events (insulin resistance, hyperglycemia, and dyslipidemia) contribute to metabolic pathway dysregulation events that are interactive and collectively result in cellular damage and nerve dysfunction.

Figure 3.

Determination of intraepidermal nerve fiber density from punch skin biopsy. (Left) A 3-mm skin biopsy was removed and processed for protein gene product 9.5 (PGP 9.5) immunocytochemistry. (A and B) Arrows indicate PGP 9.5–positive fibers in the epidermis of a person without diabetes (A) and in that of a person with diabetes (B). Scale bar=50 μm. Photographs courtesy of Douglas E. Wright, PhD.

Appendix.

Preexercise Considerations and Exercise Goals^,