I woke up one morning with my right hand completely dead. Not tingly — dead. Like someone had replaced my arm with a rubber prop. It took ten minutes of shaking and flexing before feeling came back. I panicked and googled “stroke symptoms.” It was not a stroke. It was how I was sleeping.

Your Sleeping Position Is Crushing Your Nerves

The most common cause of nighttime hand numbness is positional — you are compressing a nerve while you sleep. Three nerves run from your neck to your hand, and each can get pinched in a different sleeping position.

The median nerve gets pinched if you sleep with your wrist bent — the “fetal position with curled hands” is the worst for this. The ulnar nerve gets compressed if you sleep with your elbow bent sharply. The radial nerve gets squished if you sleep with your arm under your body or under your partner’s head.

How to Tell Which Nerve

• Thumb, index, and middle fingers numb → median nerve. Fix: wear a wrist brace at night. The kind with a rigid insert that keeps your wrist straight. Ten dollars at any drugstore.
• Pinky and ring finger numb → ulnar nerve. Fix: wrap a towel loosely around your elbow to prevent it from bending past 90 degrees. Or sleep with your arm straight at your side.
• Back of the hand numb → radial nerve. Fix: stop sleeping on your arm. Hug a pillow instead so the arm has somewhere to go that is not under you.

When It Is More Than Position

If changing your sleep position does not fix it within a week, see a doctor. Carpal tunnel syndrome, a pinched nerve in your neck from a disc problem, and diabetic neuropathy can all cause similar symptoms. Red flags: numbness during the day, weakness dropping things, or pain that shoots up your forearm.

My problem was the ulnar nerve. A towel around my elbow for three nights fixed it completely. I felt a little ridiculous going to bed with a towel strapped to my arm, but it beats waking up with a dead hand.