Why do we rub our eyes when we're tired?

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.

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