Peripheral neuropathy, the chronic nerve illness caused by conditions such as diabetes, cancer, infections and autoimmune diseases, was thought to be completely irreversible. But recent case studies suggest early onset of neuropathy has a chance to be reversed using something everyone can afford: exercise.
“Exercise will help any healing process,” says physiatrist and chronic pain specialist Andrea Furlan. However, we need more evidence about what type of exercise helps because not all neuropathic pain can be reversed, adding there are no clinical guidelines for exercise prescription that can support nerve health while managing peripheral neuropathy (PN). The typical 150 minutes of moderate to vigorous exercise a week recommended for the general population is all clinicians and patients have to follow.
Approximately one per cent of adults worldwide have PN. Symptoms include numbness, loss of sensation or motor control in one’s peripheral nerves – the wires of nerves that travel across the body receiving and sending signals to and from the brain and spinal cord. Although diabetes is the leading cause in most Western countries, there are more than 100 types of PN and 200 causes, including injury and genetics.
“Almost all peripheral neuropathies usually start in the small nerve fibers, that’s why pain is the biggest symptom,” says neurologist Ahmet Hoke, professor of neurology and neuroscience and director of the Merkin Peripheral Neuropathy and Nerve Regeneration Center at the Johns Hopkins University School of Medicine.
The small nerve fibers are responsible for sensation such as pain and temperature changes. Hoke says that the small nerves have some capacity to regenerate, but they do so very slowly. On average, peripheral nerves can regenerate at a rate of one inch per month, which is consistent across all species. Taller people are more susceptible to developing PN and peripheral nerve regrowth can be challenging since their nerves are longer, says Hoke.
Although there are no clinical treatments for reversing PN, symptoms can be managed with pain relievers, lifestyle changes and exercise though Hoke says that for many patients with neuropathy, walking can be painful, so introducing exercise can be a challenge.
“You have to be very careful. You can’t go hard. You have to do every kind of exercise at a more moderate level because otherwise you could do more damage to your muscles,” says Linda Petiot, president of the Calgary Neuropathy Association. “I can still build strength, I know I can do that, but I just have to do everything slowly. And I think that’s true of anybody with peripheral neuropathy.”
Petiot attributes exercise and lifestyle changes to keeping her neuropathy, Charcot-Marie-Tooth (CMT) disease, from “not getting worse.”
There are more than 160 types of CMT. The condition is genetic and early symptoms can include tingling, muscle weakness and challenges with balance, leading to tripping and falling. Though Petiot says she’s always struggled with the disease, though with lighter symptoms, she was only diagnosed after her father was diagnosed later in life when his symptoms worsened. After genetic testing, she, her father and her son were all found to have the same gene expression that causes CMT.
“I had symptoms all my life, like falling down and nerve pain and weakness,” says Petiot. “I don’t really know that I can manage the progression. I like to tell myself that I am by doing all the things that are healthy: I don’t drink alcohol anymore, I try to avoid sugars, I try to exercise.”
She consumes a healthy diet and combines strength training with low-impact cardio, such as biking, swimming and using the elliptical machine.
Hoke and Furlan both suggest that patients start with small bouts of aerobic and resistance training that feel doable, and then slowly build stamina over the course of introducing exercise.
Often, patients with diabetes who develop neuropathy cannot run or walk, says Hoke. He recommends those patients swim or use a stationary bicycle and combine resistance training with weights or resistance bands.
“That combination seems to make the biggest impact,” says Hoke. “We want to promote the microenvironment surrounding the nerve. And you also want to support the nerve growing forward toward the muscle.”
Exercise releases exerkines – molecules released from various tissues to regulate metabolism and promote wellbeing – and nerve growth factor, which support the growth and protection of nerves. Furlan tells her patients about the benefits of exercise on brain and nerve health, and how these molecules released during exercise can prevent dementia, Alzheimer’s, memory loss and cognitive impairment.
Pain is a neurological phenomenon that is more than just biological damage to a structure in the body, says Furlan. In clinic, she uses the biopsychosocial model to address how the patient is interpreting the sensory information that stems from thought, worries, emotions and environmental factors.
With exercise prescription, she tries to encourage social activities that patients enjoy to ensure consistency, such as recreational sports with friends or playing with grandchildren. If the patient already has a relatively active lifestyle due to the nature of their work, she encourages that movement to continue.
There are instances where exercise may not always be beneficial at first. Furlan mentions sciatica, a form of entrapment neuropathy in the lower spine, that requires rest until the inflammation decreases and the nerve recovers. As soon as the recovery begins, gentle exercise can help and the condition can be treated.
The evidence that exercise can reverse PN is shown in animals and a few human case studies, says Furlan. The timing of starting an exercise regimen is crucial and dependent on the condition; however, she adds that the research is concentrated on the pharmacological interventions rather than the exercise prescriptions that could benefit patients.
Petiot mentions that patients who attend support groups at the Calgary Neuropathy Association don’t always have access to resources needed to exercise for their neuropathy. She was able to see an athletic therapist and physiotherapist early-on, but that is not the reality for most patients. She stopped seeing a neurologist after receiving a diagnosis and then had to advocate for herself at her family doctor’s office to be referred to a neuromuscular clinic that supports her CMT.
Most patients with chronic pain are treated by a family physician, says Furlan but adds that an interdisciplinary team consisting of a physiotherapist, mental health provider and pharmacist is needed.
Out-of-pocket costs for physiotherapy, massage therapy and mental health services can be costly, says Petiot, especially when private insurance is limited to a certain number of sessions. She notes that some patients don’t have private insurance because they are unable to work due to their neuropathy pain.
“If we ask every neurologist: ‘Do you think exercise is beneficial for your patient?’ Everybody will say yes,” says Furlan, “The thing is how do you communicate that with patients? And how do you address the barriers that patients have? I think that’s what’s lacking in training.”
In the meantime, the next step for researchers and neurologists is to create clinical guidelines for exercise prescription that can support nerve health when managing PN.
“In terms of disease-modifying treatments, exercise is the only one where we have some clinical trial data,” says Hoke.
