The holidays are a time of sheer excitement for most kids – but for one mother in the U.K. – she’s hoping her 2-year-old daughter feels anything but thrilled this Christmas.

That’s because little Holly Cleveland suffers from a rare condition called reflex anoxic seizures (RAS), which cause her heart to stop and her breathing to halt if she gets too excited, the Daily Mail reported.

This type of seizure, which is a not a form of epilepsy, is triggered by a temporary cutting off of the blood supply to the brain. It can be induced by unexpected bouts of pain, shock and excitement.

“I have been assured that her heart will always start again, but every time it happens, I can’t help panicking,” Holly’s mom, Tina Cleveland, told the newspaper. “What mother wouldn’t if her baby was lying on the floor not breathing for half a minute? It’s horrendous.”

In an effort to keep Holly’s excitement in check, Cleveland said she even put up the Christmas tree early to try and get Holly used to the bright lights.

“It’s heartbreaking to see her little face light up and then have to immediately calm her down again,” Cleveland said. “I’ve even avoided asking her what present she wants because I don’t want her to get too excited when she sees it.

RAS occurs in an estimated eight out of every 1,000 preschool children. There’s no cure, but the attacks usually grow more infrequent as the child gets older.

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Click here to read more about RAS.