It seemed like a normal start to the day for one Chinese man. He woke up, stretched and yawned -- then he felt a throbbing pain in his chest.

Still, he didn't realize anything was amiss and headed to work. It wasn't until later, after his coworkers brought him to the Central Hospital of Wuhan, that the man discovered the source of his pain. According to local news reports, the force of the yawn had made his lung "collapse."

Doctors reportedly diagnosed the 26-year-old, whose full name was withheld in local reports, with spontaneous pneumothorax, a particular type of collapsed lung. The condition occurs when air builds up in the space outside the lung, putting pressure on the organ and stopping it from fully expanding. Though often precipitated by a chest injury or lung disease, pneumothorax can occur without cause.

While bizarre, this kind of collapsed lung isn't entirely out of the ordinary. In fact, Central Hospital of Wuhan treated another man for spontaneous pneumothorax on the same day, according to Changjiang Daily.

Chen Baojun, the hospital director's of cardiothoracic surgery, explained that tall, thin men are particularly susceptible, the Global Times reports. The 26-year-old man was reported to have a lanky frame at 1.8 meters (about 5 feet 11 inches) tall and 60 kilograms (132 pounds).