Why your longest nerves are the first to fail in peripheral neuropathy

Health · Published 29 September 2026 Swipe more like this →

In short: Peripheral neuropathy is not a single disease, but a diverse group of conditions where the nerves outside your brain and spinal cord are damaged. Often starting in the feet, this nerve failure can disrupt everything from your ability to walk to your body's most basic automatic functions.

The peripheral nervous system acts as a vast communication network, connecting the brain and spinal cord to the rest of the body. It is composed of three distinct nerve types: sensory nerves, which process touch and pain; motor nerves, which command muscle movement; and autonomic nerves, which regulate involuntary processes like heart rate, digestion, and blood pressure. When these nerves are damaged, the resulting symptoms depend entirely on which fibers are affected, ranging from tingling and numbness to muscle weakness or even fainting.

The most common pattern of damage is polyneuropathy, which typically begins in the feet. This occurs because the longest nerves in the body are often the most vulnerable to metabolic stress. In a process known as distal axonopathy, the axons—the long, thread-like parts of nerve cells—are damaged in proportion to their length. While diabetes is the leading cause of this condition in the UK, nerve damage can also stem from physical trauma, viral infections like shingles, vitamin deficiencies, or exposure to toxins like heavy metals and certain chemotherapy drugs.

Diagnosis is critical because early intervention can limit permanent damage. Healthcare providers may use electromyography or nerve conduction studies to classify the condition based on the number of nerves involved, such as mononeuropathy, which affects a single nerve, or mononeuritis multiplex, which impacts several disparate nerves. If left untreated, complications can be severe, including chronic pain, infected foot ulcers, and, in extreme cases, amputation. Recent research has also begun to uncover the role of the NAD+/SARM1 signaling pathway in the degeneration of axons, suggesting that the nervous system is deeply intertwined with the body's metabolic health.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

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