Rat Study Suggests Exercise Can Reduce Nerve PainA new study finds that exercise may be a “new” method to treat pain related to nerve damage.

Researchers discovered exercise reduces certain inflammation-promoting factors called cytokines. This discovery supports the use of exercise as a nondrug treatment for neuropathic pain.

The study is published in the journal Anesthesia & Analgesia.

The results support exercise as a potentially useful nondrug treatment for neuropathic pain.

Neuropathic pain is a common and difficult-to-treat type of pain caused by nerve damage, seen in patients with trauma, diabetes, and other conditions. Phantom limb pain after amputation is an example of neuropathic pain.

In the study, Yu-Wen Chen, Ph.D., and colleagues examined the effects of exercise on neuropathic pain induced by sciatic nerve injury in rats.

After nerve injury, some animals performed progressive exercise—either swimming or treadmill running—over a few weeks. The researchers assessed the effects of exercise on neuropathic pain severity by monitoring observable pain behaviors.

The results suggested significant reductions in neuropathic pain in rats assigned to swimming or treadmill running. Exercise reduced abnormal responses to temperature and pressure—both characteristic of neuropathic pain.

Exercise also led to reduced expression of inflammation-promoting cytokines in sciatic nerve tissue—specifically, tumor necrosis factor-alpha and interleukin-1-beta. This finding confirmed the hypothesis that inflammation and pro-inflammatory cytokines play a role in the development of neuropathic pain in response to nerve injury.

Exercise also led to increased expression of a protein, called heat shock protein-27, which may have contributed to the reductions in cytokine expression.

Pain from nerve damage is characterized by both a burning sensation and by numbness and is often not controlled by conventional pain medications. Antidepressant and antiepileptic drugs may be helpful, but have significant side effects. Exercise is commonly recommended for patients with various types of chronic pain, but there are conflicting data as to whether it is helpful in neuropathic pain.

The new results support the benefits of exercise in reducing neuropathic pain, though not eliminating it completely. In the experiments, exercise reduced abnormal pain responses by 30 to 50 percent.

Researchers also believe the study provides new evidence that inflammation contributes to the development of neuropathic pain. Study results also support use of exercise as a nondrug therapy for neuropathic pain—potentially reducing the need for medications and resulting side effects.

Source: Anesthesia and Analgesia

Rat exercising photo by shutterstock.