Alcohol drops the density of fluid in your inner ear's balance sensor, so it fires spinning signals when you lie down.
A Mass Eye and Ear vestibular specialist explains the cupula ends up lighter than the surrounding fluid, moves wrongly, and your brain reads rotation. It passes as blood alcohol falls. Manage it with side-lying, water, and stillness. The boundaries: vertigo persisting into the next day, vertigo with double vision, slurred speech, weakness, or severe headache, or vertigo without drinking needs assessment, since sudden vertigo can signal a stroke or a vestibular disorder, and the NHS says recurring vertigo deserves a GP.
What to do
Common questions
Why do I get the spins when I lie down after drinking?
The spins are your inner ear lying to you. Each inner ear holds semicircular canals filled with fluid, and a sensor called the cupula floats in it; when alcohol enters your bloodstream it lowers the density of the cupula's fluid relative to its surroundings, so the sensor moves when it should not and your brain reads spinning. A vestibular specialist at Mass Eye and Ear explains this is why the spins classically hit when you lie down and close your eyes after heavy drinking: the position change moves the mismatched sensor. The room-spinning can come with nausea and cold sweats, and it passes as your blood alcohol falls, which is why it often wakes you a few hours in or fades by morning. What to do in the moment: lie on your side with one foot on the floor if it helps you feel anchored, keep the room cool, sip water, and do not try to drive or walk stairs. Spinning that continues the next day without alcohol in your system, arrives with double vision, slurred speech, weakness, or a severe headache, or starts happening without drinking is not the spins: sudden vertigo can signal a stroke or a vestibular disorder, and the NHS says vertigo that will not go away or keeps coming back needs a GP.