Why do we rub our eyes when we’re tired?
Maybe now you have a good excuse after an all-night Disney marathon.
Asked by: Matthew Cahill, Liverpool
Tired eyes get dry, and rubbing stimulates the lacrimal glands to produce more fluid. Tiredness also closes your eyes, so you may rub to keep them open. Finally, there’s a connection between the muscles that move your eyes around and your heart. When these muscles are stimulated, a reflex slows the heart. This might be relaxing if you feel very tired.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.
