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A squashed cable

Why Does Your Foot Go to Sleep?

Sitting on a nerve interrupts its signals, and the pins and needles are the signals coming back.

1 You sit on anerve2 Signals areinterrupted3 Restartingfeels like pinsand needles
The tingle is recovery, not damage.

  1. Step 1 of 5

    Nerves are cables, and cables can be pinched.

    Sitting cross-legged A nerve pinched againstbone

    Sensation travels as electrical signals along long fibres. Pressing hard on a nerve where it runs near a bone squeezes those fibres shut.

  2. Step 2 of 5

    Numbness is the absence of a signal.

    Normal Steady stream ofsignalsPinched Nothing arriving —feels absent

    Your foot has not gone anywhere. Your brain simply stops hearing from it, and a limb it cannot hear from feels absent and heavy.

  3. Step 3 of 5

    Blood supply matters less than you think.

    What causes itPressure onthe nerveReduced bloodflow

    People assume it is blood, but pressure on the nerve itself is the main cause. Nerves are more delicate than the vessels beside them.

  4. Step 4 of 5

    Pins and needles are the restart.

    1 Pressurereleased2 Fibres fire outof order3 Read asprickling

    When pressure lifts, fibres wake up unevenly and fire bursts of nonsense at once. Your brain reads that noise as prickling.

  5. Step 5 of 5

    It fades in a fixed order.

    1 Sharp tingling2 Dull ache3=Back to normal

    The thick, fast fibres recover first and the fine ones last, so the sensation goes tingling, then aching, then normal — usually within minutes.

    Numbness that arrives without pressure, or does not fade, is worth a doctor's attention — that is a different problem entirely.

The short version

Sitting on a nerve blocks its signals, so the limb feels absent, and the pins and needles are its fibres restarting out of order.

Try it yourself

Rest your elbow on a hard table for a minute. The tingling in your little finger is the same nerve, squashed at the elbow.

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