Why does sweat sting your eyes, but tears do not? © Getty Images

Why does sweat sting your eyes, but tears do not?

Awww, dry your eyes.

Asked by: John Radford, High Wycombe

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Tears and sweat both have approximately the same salinity, but sweat contains oils and hormones that could irritate the eyes. The sweat that runs into your eyes has also run over your hair and forehead first, so it has had plenty of opportunity to pick up dust and grime along the way.


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