Diabetic Peripheral Neuropathy Understanding Benefits of Safe Exercise Therapy

 Before 2009, a Standards of Medical Care in Diabetes position statement recommended, “in the presence of severe peripheral neuropathy, it may be best to encourage non–weight-bearing activities such as swimming, bicycling, or arm exercises.”1 However, an important study randomised people with DPN into a weightbearing activity group and found that weightbearing activity did not increase the rate of foot ulcers.2 This led to a change in recommendations in the latest Standards of Medical Care paper.3

The current position does not recommend against weightbearing exercise except to caution, “All individuals with peripheral neuropathy should wear proper footwear and examine their feet daily to detect lesions early. Anyone with a foot injury or open sore should be restricted to non–weight-bearing activities.” Nevertheless, patients and practitioners alike may continue to practice an abundance of caution. Studies show a strong association between DPN and reduced activity levels.4,5 Authors have connected the loss of sensation with impaired balance, altered gait, and increased risk of falling.

What’s more, peripheral neuropathy deprives a person of pressure and pain input that typically protects people from foot injury during exercise. Additionally, people with diabetes prove more likely to have tissues that are thicker, stiffer, and more susceptible to injury.6 Despite studies finding that weightbearing exercise among patients with DPN does not increase fall injuries7 and does not increase foot ulcers, the facts of DPN seem to merit serious additional caution. On the other hand, exercise therapy offers important benefits.

The usual patterns of decline can be transformed into patterns of improvement. While the benefits of exercise on metabolic status are obvious, research also suggests that exercise in DPN mediates peripheral nerve plasticity through mechanisms in addition to metabolic status.8

For the tissues of the foot, prolonged levels of low stress lead to decreased tolerance of stress and an even lower threshold for injury.9,10 Patients with diabetic peripheral neuropathy who engage in exercise therapy regularly realize improvements in nerve conduction velocity,11 pain interference,12 general fatigue,13 balance,14 gait,15 and mobility.16 In animal models, exercise in DPN leads to decreased pain,17 normalised epidermal innervation,18 enhanced nerve regeneration,19 and restored electrophysiological function.20

Weightbearing exercise for patients with DPN offers theoretical risks and proven benefits. The solution for managing those risks effectively is a prescription for exercise physiology. To ensure safety, exercise programs closely supervised by an exercise physiologist will include ongoing screening for integumentary, nervous, musculoskeletal, vascular, endocrine, and cardiovascular systems. Footwear will also be evaluated before each exercise session, and patients will be thoroughly trained in all these aspects of safe exercise. Exercise physiology can implement multi-focused, supervised exercise plans designed to achieve aerobic, gait, balance, and strength benefits, while triggering the non-metabolic mechanisms associated with nerve improvement. The treatment plans will give people with DPN the confidence and motivation they need to improve activity levels long-term, empowering them to have greater control over their disease and to reverse the common patterns of decline.

References

1. American Diabetes Association. Stan-dards of medical care in diabetes: 2008. Diabetes Care. 2008;31:S12–S54.

2. LeMaster JW, Mueller MJ, Reiber GE, Mehr DR, Madsen RW, Conn VS. Effect of weight-bearing activity on foot ulcer incidence in people with diabetic peripheral neuropathy: feet first randomized controlled trial. Physical Therapy. 2008 Nov 1;88(11):1385-98.

3. American Diabetes Association. Standards of medical care in diabetes: 2016. Diabetes Care. 2016;39(suppl 1):S1– S112.

4. Maluf KS, Mueller MJ. Comparison of physical activity and cumulative plantar tissue stress among subjects with and without diabetes mellitus and a history of recurrent plantar ulcers. Clinical Biomechanics. 2003 Aug 1;18(7):567-75.

5. Van Sloten TT, Savelberg HH, Duimel-Peeters IG, Meijer K, Henry RM, Stehouwer CD, Schaper NC. Peripheral neuropathy, decreased muscle strength and obesity are strongly associated with walking in persons with type 2 diabees without manifest mobility limitations. Diabetes Research and Clinical Practice. 2011 Jan 1;91(1):32-9.

6. Shah KM, Clark BR, McGill JB, Lang CE, Maynard J, Mueller MJ. Relationship between skin intrinsic fluorescence—an indicator of advanced glycation end products—and upper extremity impairments in individuals with diabetes mellitus. Physical Therapy. 2015 Aug 1;95(8):1111-9.

7. Mueller MJ, Tuttle LJ, LeMaster JW, Strube MJ, McGill JB, Hastings MK, Sinacore DR. Weight-bearing versus nonweight-bearing exercise for persons with diabetes and peripheral neuropathy: a randomized controlled trial. Archives of Physical Medicine and Rehabilitation. 2013 May 1;94(5):829-38.

8. Kluding PM, Bareiss SK, Hastings M, Marcus RL, Sinacore DR, Mueller MJ. Physical training and activity in people with diabetic peripheral neuropathy: paradigm shift. Physical Therapy. 2017 Jan;97(1):31-43.

9. Armstrong DG, Lavery LA, Holtz-Neiderer K, Mohler MJ, Wendel CS, Nixon BP, Boulton AJ. Variability in activity may precede diabetic foot ulceration. Diabetes Care. 2004 Aug 1;27(8):1980-4.

10. Maluf KS, Mueller MJ. Comparison of physical activity and cumulative plantar tissue stress among subjects with and without diabetes mellitus and a history of recurrent plantar ulcers. Clinical Biomechanics. 2003 Aug 1;18(7):567-75.

11. Dixit S, Maiya AG, Shastry BA. Effect of aerobic exercise on peripheral nerve functions of population with diabetic peripheral neuropathy in type 2 diabetes: a single blind, parallel group randomized controlled trial. Journal of Diabetes and its Complications. 2014 May 1;28(3):332-9.

12. Yoo M, D'Silva LJ, Martin K, Sharma NK, Pasnoor M, LeMaster JW, Kluding PM. Pilot study of exercise therapy on painful diabetic peripheral neuropathy. Pain Medicine. 2015 Aug 1;16(8):1482-9.

13. Fisher MA, Langbein WE, Collins EG, Williams K, Corzine L. Physiological improvement with moderate exercise in type II diabetic neuropathy. Electromyography and Clinical Neurophysiology. 2007 Jan 1;47(1):23-8.

14. Akbari M, Jafari H, Moshashaee A, Forugh B. Do diabetic neuropathy patients benefit from balance training?. Journal of Rehabilitation Research & Development. 2012 Mar 1;49(2).

15. Allet L, Armand S, De Bie RA, Golay A, Monnin D, Aminian K, Staal JB, de Bruin ED. The gait and balance of patients with diabetes can be improved: a randomised controlled trial. Diabetologia. 2010 Mar;53:458-66.

16. Kruse RL, LeMaster JW, Madsen RW. Fall and balance outcomes after an intervention to promote leg strength, balance, and walking in people with diabetic peripheral neuropathy:“feet first” randomized controlled trial. Physical Therapy. 2010 Nov 1;90(11):1568-79.

17. Chen YW, Hsieh PL, Chen YC, Hung CH, Cheng JT. Physical exercise induces excess hsp72 expression and delays the development of hyperalgesia and allodynia in painful diabetic neuropathy rats. Anesthesia & Analgesia. 2013 Feb 1;116(2):482-90.

18. Groover AL, Ryals JM, Guilford BL, Wilson NM, Christianson JA, Wright DE. Exercise-mediated improvements in painful neuropathy associated with prediabetes in mice. Pain®. 2013 Dec 1;154(12):2658-67.

19. Malysz T, Ilha J, do Nascimento PS, De Angelis K, Schaan BD, Achaval M. Beneficial effects of treadmill training in experimental diabetic nerve regeneration. Clinics. 2010 Jan 1;65(12):1329-37.

20. Li H, Shen Z, Lu Y, Lin F, Wu Y, Jiang Z. Muscle NT-3 levels increased by exercise training contribute to th