It's bad luck to sleep with socks on

This superstition comes from the practice of putting white tabi socks on people when they die. Imitating death by wearing the same clothes as a dead person is said to bring one's own death closer.

Verity:

If mimicking a condition of death actually did bring one's death closer, then it seems more likely that other activities would actually be the cause rather than just wearing socks.

For example, the usual position for a corpse is lying on their back. Sleeping on your back could certainly be inadvisable if you have apnoea syndrome, and your doctor might have advised you to sleep on your side to reduce the risk of suffocating. (Your doctor might tell you not to "adopt a supine recumbent posture", but that just means don't lie on your back in bed, and charge you extra for using posh words.)

Another way to bring death closer is to adopt the breathing condition of a dead person; i.e., stop breathing.

Please don't try that.

Actually wearing socks in bed, white or any other colour, is quite a healthy way to sleep. Your body increases melatonin production near the end of the day to prepare you for sleep by dropping your core body temperature. It does this by increasing blood flow to the hands and feet, a natural process (called distal vasodilation) which is helped by wearing socks.