ORLANDO—Resistance training improved symptoms of neuropathy and the cardiovascular risk factor profile of patients with type 2 diabetes mellitus and peripheral neuropathy, according to a recent study. A 12-week program of resistance training improved calf strength, blood pressure, and HDL cholesterol levels, significantly reduced scores on the Michigan Neuropathy Screening Instrument and improved vibration sense in both feet of study participants. “A resistance training program really improves muscle strength and neurologic functioning in the lower extremities—which is where the exercise in this study was directed—and it decreases a number of cardiovascular risk factors,” said Sri Prakash L. Mokshagundam, MD.

Typically, patients with type 2 diabetes mellitus are encouraged to exercise, but for elderly patients with both type 2 diabetes mellitus and peripheral neuropathy, aerobic exercise cannot be recommended since excessive pressure on the feet can lead to callus formation and foot ulceration, Dr. Mokshagundam explained. These patients may also have balance problems, he added. Dr. Mokshagundam is an Associate Clinical Professor in the Division of Endocrinology and Metabolism at the University of Louisville.

“Our aim was to look at resistance training, which basically is the use of weights and machines, to see if that would be an effective way of overcoming the problem of doing routine exercise,” he said. Not only might such exercise improve cardiovascular risk factors such as blood pressure and cholesterol levels, Dr. Mokshagundam said, but the literature concerning patients with nondiabetic neuropathy and those with arthritis suggests that such exercise might also have a beneficial effect on pain symptoms, perhaps by relieving muscle spasm. In addition, if a resistance training program could reduce blood glucose as does aerobic exercise, it could improve glucose control and perhaps reverse the neuropathy to some degree, he suggested.

In this study, which was presented at the American Diabetes Association’s 64th Annual Scientific Sessions, 25 elderly patients with type 2 diabetes mellitus and clinical evidence of peripheral neuropathy participated in a 12-week program of resistance training aimed at the lower extremities. Sessions were 30 minutes long, three times per week. This group is at high risk for complications related to exercise, including angina or hypoglycemia, Dr. Mokshagundam noted, so the program was carried out under medical supervision. Patients exercised with increasing intensity according to their ability.

Before and after the 12-week program a clinical evaluation that included anthropometric measures, blood pressure, fasting glucose, lipid profile, and hemoglobin A^1c was carried out. In addition, neuropathy scores were measured before and after the program using the Michigan Neuropathy Screening Instrument, functional testing was evaluated using the Neuropathy Disability Score, pain scores were measured using a visual analog scale, and participants underwent an evaluation of dynamic muscle strength.

Dr. Mokshagundam noted that the patients participated consistently, with 24 of 25 patients completing the program, resulting in an attendance rate of more than 90%. “Most of them came to the sessions, which was kind of interesting to us because it indicates that if you do provide access to these facilities for them, they will do it [exercise].”

In this group, resistance training resulted in significant increases in muscle strength in the calf and hamstring and performance in the chair exercise, the researchers reported, with improvements ranging from 40% to 60%, depending on the muscles measured. There was also a significant reduction of about 5 cm in the average waist circumference in these patients; waist circumference is a stronger cardiovascular risk factor than body weight, he acknowledged. Blood pressure, both systolic and diastolic, was reduced with exercise by about 10 and 6 mm Hg respectively, and HDL cholesterol increased significantly.

There was also a significant reduction from baseline in Michigan Neuropathy Screening Instrument scores, with average scores decreasing from 7.55 to 6.09. Significant improvements were seen in the Neuropathy Disability Score and visual analog pain scale scores, he observed, “so these patients actually all felt much better.” Vibration sense in the foot measured by the on/off method was significantly improved in both feet after the program.

While tests of “functional fitness,” or effects on activities of daily living, were not systematically measured in this study, patients did report improvements anecdotally. For example, Dr. Mokshagundam related, “Some patients who could not on a regular basis walk to their car could do that very easily after the exercise program.”

Finally, there were reductions in fasting blood sugar levels of about 20 mg/dL on average, and hemoglobin A^1c levels also dropped, although not significantly. In some patients, the reductions required some adjustment of their diabetic medications to prevent hypoglycemia.

Although the study has shown that resistance training is a viable substitute for aerobic exercise, Dr. Mokshagundam said, one drawback is that resistance training requires specialized equipment and facilities that may make access a problem for some. However, “If I tell them to walk, they can do it wherever,” he said.

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—Susan Jeffrey

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