Symptoms

Carpal Tunnel: Why Your Hands Go Numb at Night and How to Fix It

By Health 656 Editorial Team 2026-03-22 8 min read

You wake at 3 AM with your hand numb, tingling, and on fire. You shake it, flex your fingers, and the feeling slowly returns. It happens again the next night. And the next. Eventually the numbness is there during the day too — when you drive, hold your phone, type at your desk. You drop things. Your grip weakens. Carpal tunnel syndrome (CTS) is the most common nerve compression disorder, affecting roughly 3 to 6 percent of the adult population according to a study in the Journal of the American Medical Association. A study in the Journal of General Internal Medicine estimated that CTS costs the US economy $2 billion annually in medical care and lost productivity. It is particularly common in women (3 times more than men), people who perform repetitive hand movements, and during pregnancy. This guide explains what is compressing your nerve, why it happens, and what treatments have the strongest evidence.

What Is Happening Inside Your Wrist

The carpal tunnel is a narrow passageway on the palm side of your wrist, about the diameter of your thumb. It is formed by the wrist bones (carpals) on three sides and a tough band of connective tissue called the transverse carpal ligament on the top. Through this tight space pass nine flexor tendons and one nerve — the median nerve.

The median nerve controls sensation in your thumb, index finger, middle finger, and half of the ring finger. It also controls the muscles at the base of the thumb. When anything causes the space inside the carpal tunnel to shrink or the contents to swell, the median nerve gets compressed. This compression disrupts the nerve's ability to send signals — producing numbness, tingling, and eventually weakness.

The tendon sheaths are the usual culprits. Repetitive hand movements cause the synovium (lining) around the tendons to thicken and swell. Fluid retention — common in pregnancy, hypothyroidism, diabetes, and menopause — increases pressure inside the tunnel. Inflammatory conditions like rheumatoid arthritis can cause synovial swelling. Wrist fractures or dislocations can narrow the tunnel structurally.

A 34-year-old software developer noticed tingling in both hands during long coding sessions. She bought an ergonomic keyboard, which helped during the day, but nighttime numbness worsened. "I would wake up shaking my hands like I was trying to get water off them," she said. Nerve conduction studies confirmed moderate CTS. A combination of night wrist splints and a workplace ergonomic assessment resolved her symptoms within 2 months.

Symptoms — The Pattern Tells the Story

CTS follows a predictable progression. Early stage: Intermittent numbness and tingling in the thumb, index, middle, and ring fingers, particularly at night (because most people sleep with flexed wrists, which compresses the nerve). Shaking the hand (flick sign) temporarily relieves symptoms. Moderate stage: Daytime symptoms appear during activities that flex or extend the wrist — driving, holding a phone, typing, gripping. Numbness becomes more persistent. Fine motor tasks become difficult — buttoning shirts, picking up small objects. Severe stage: Constant numbness. Muscle wasting at the base of the thumb (thenar atrophy). Weakness — dropping objects, difficulty gripping. At this stage, nerve damage may become permanent if not treated.

An important clue: CTS affects the thumb, index, middle, and half of the ring finger — but NOT the little finger. The little finger is served by a different nerve (the ulnar nerve). If your entire hand is numb, the problem is likely not carpal tunnel.

Nighttime symptoms are often the earliest and most prominent feature. A study in the Journal of Hand Surgery found that 95 percent of CTS patients reported nighttime symptoms, compared to 60 percent with daytime symptoms. The wrist naturally flexes during sleep, increasing pressure in the carpal tunnel for hours.

Diagnosis — Simple and Reliable

Clinical tests: The Phalen test (holding wrists fully flexed for 60 seconds — if tingling or numbness appears in the median nerve distribution, the test is positive) has a sensitivity of roughly 70 percent. Tinel's sign (tapping over the carpal tunnel at the wrist producing tingling) has a sensitivity of roughly 50 percent. These are screening tests — they support the diagnosis but do not confirm it.

Nerve conduction study (NCS) and electromyography (EMG): The gold standard for confirming CTS and assessing severity. NCS measures how fast electrical signals travel through the median nerve — slowed conduction confirms compression. EMG assesses whether the muscles supplied by the median nerve are functioning normally. These tests guide treatment decisions: mild CTS with normal EMG may respond to conservative treatment, while severe CTS with muscle involvement may require surgery.

A study in Muscle and Nerve found that NCS had a sensitivity of 85 to 90 percent for CTS diagnosis. However, roughly 10 to 15 percent of patients with clinical CTS have normal studies — clinical diagnosis may still be valid in these cases.

Treatment — Conservative First, Surgery When Needed

Night wrist splints: The most effective conservative treatment. A neutral wrist splint worn during sleep prevents the wrist flexion that compresses the nerve. A randomized trial in the Journal of the American Medical Association found that night splinting improved symptoms in 37 percent of patients at 4 weeks. The splint should hold the wrist in a neutral position (not bent forward or backward). Available without prescription at pharmacies. Wear nightly for at least 4 to 6 weeks before assessing effectiveness.

Corticosteroid injection: A single injection of corticosteroid into the carpal tunnel reduces swelling and provides rapid relief. A Cochrane review found significant symptom improvement at 1 month. However, relief is often temporary (weeks to months), and repeated injections carry diminishing returns. Most useful as a diagnostic confirmation (if the injection helps, the diagnosis is confirmed) and as a bridge to surgery.

Ergonomic modifications: Adjust keyboard height so wrists are neutral, not flexed. Use a mouse pad with wrist rest. Take breaks every 30 to 60 minutes during repetitive hand tasks. These reduce ongoing aggravation but alone rarely cure established CTS.

Carpal tunnel release surgery: The definitive treatment for moderate-to-severe CTS or cases not responding to conservative measures. The transverse carpal ligament is cut, releasing pressure on the nerve. Can be performed as open surgery (2-3 cm incision) or endoscopically (smaller incisions with camera guidance). A study in the Journal of Bone and Joint Surgery found that 70 to 90 percent of patients reported good to excellent outcomes after surgery. Recovery: grip strength returns within 6 to 12 weeks. Most patients return to desk work within 1 to 2 weeks and manual labor within 4 to 6 weeks. The recurrence rate after surgery is less than 5 percent.

A 52-year-old carpenter had CTS in both hands for 2 years. Night splints helped initially but symptoms progressed to constant numbness and weak grip — he could not hold a hammer. Nerve conduction studies showed severe compression with early muscle damage. He underwent carpal tunnel release on his dominant hand first, then the other hand 6 weeks later. Within 3 months, sensation had returned and his grip strength was back. "I should have done it a year earlier instead of suffering through," he said.

Common Questions

Does typing cause carpal tunnel syndrome?

Typing is associated with CTS but is not the sole cause. A large study in Neurology found that intensive computer use was a modest risk factor but that other factors — female sex, obesity, diabetes, hypothyroidism, and wrist anatomy — were stronger predictors. Proper ergonomics reduce risk but cannot eliminate it entirely.

Can carpal tunnel go away on its own?

Mild CTS, particularly when caused by a temporary condition like pregnancy, may resolve on its own. However, most cases that persist beyond a few months without treatment tend to gradually worsen. Early intervention with splinting produces the best conservative outcomes.

Is surgery the only option for severe carpal tunnel?

For severe CTS with muscle wasting (thenar atrophy) or constant numbness, surgery is strongly recommended because nerve damage may become permanent without decompression. For mild to moderate CTS, a trial of conservative treatment (splinting, injection) is appropriate first. If conservative treatment fails after 3 to 6 months, surgery should be considered.

Will carpal tunnel come back after surgery?

The recurrence rate after carpal tunnel release is less than 5 percent. Once the ligament is cut, it heals in a lengthened position, providing more space for the nerve permanently. Most patients experience lasting relief.

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