A story doing the rounds is claiming that a woman in China “lost 10 years of memories” after going to the toilet with excessive force. As reported by Sky Post, a tabloid newspaper in Hong Kong, a son told the story of how his mother had been suffering from severe constipation. After relieving herself in the bathroom, she found she suddenly suffered some acute problems with her memory.
For the following eight hours, she was seemingly unable to remember anything from the past 10 years, according to her family. She was taken to the hospital where she stayed a night, but her memory had returned by the morning. Doctors carried out an examination on the woman and concluded her health, both physical and mental, was fine. She was eventually sent home from the hospital but still has no recollection of those eight hours after she visited her bathroom.
Granted, Chinese tabloid stories based on anonymous blog posts aren’t perhaps the most reliable of sources. Equally, peer-review medical journals don’t appear to be overly interested in the ins and outs, as it were, of constipation-related fainting and amnesia. All of this makes it fairly hard to confirm the veracity of the story. Nevertheless, it might not be as ludicrous as it first sounds – in theory, at least.
In all likelihood, excessive straining caused her to have vasovagal syncope, commonly known as fainting and losing consciousness. Just like the so-called “weight-lifters’ blackout,” it’s not uncommon to lose temporarily consciousness if you strain too hard and hyperventilate due to a sharp spike in heart rate and blood pressure followed by a dramatic drop, resulting in a temporary reduction of blood flow to the brain.
It’s also possible, although not common, to suffer from temporary amnesia after fainting, especially among older people. This is because the lack of blood flow can temporarily meddle with the brain's regions associated with memory, such as the hippocampus and reticular activating system.
That's the theory, at least. However, it remains unclear whether this case actually happened recently in Hong Kong or whether it's an urban legend for the age of online media. We'll leave that question up to Snopes.