In July 2014, a mother in her 30s stood in her kitchen staring at a pot of boiling water while her kids played nearby.

She was exhausted, far beyond typical fatigue. For months, in fact, she'd felt drained, struggling just to get out of bed each day.

Her doctors hadn't found anything wrong, so she had pushed through.

But just then, she felt a tickle in her throat, and it turned into this violent coughing fit.

She struggled to breathe, and when it finally stopped, she wiped her mouth with a dish towel.

And the moment she pulled the towel away, she froze because it was covered in blood.

From Ballin Studios and Wondry, I'm Mr. Ballin, and this is Mr. Ballin's medical mysteries,

where every week we will explore a new baffling mystery originating from the one place we all can't escape, our own bodies.

So, if you like today's story, please sneak into the Follow Button's house during the holidays

and replace all their

presents under the tree with boxes full of old computer parts, then call in a bomb thread on

their house on Christmas morning.

This episode is called Running on Empty.

In early 2014, Sarah Weber walked through the front door of her home in Massachusetts

after a long day at the sports supply company she started with her husband Paul.

They were both avid runners, and they had turned their passion

into a business, selling water belts and other sports products online. But owning their company

meant the workday was never really done, and so sometimes Sarah's life felt like a three-ringed

circus. As Sarah took off her jacket, her three kids, ages three, five, and seven, came running up to her to give

her a hug. Sarah liked to get down on her knees and greet all three of them at their level,

but tonight, the effort made her wince. She'd been feeling so tired lately that she hadn't run

in a while, and now just bending down she could feel all this strain in her muscles.

...