--- title: "Fitness Trackers Say This Coffee Cup Has a Pulse. Wait, What?" description: "Chinese website Abacus found that a toilet paper roll had a pulse using Xiaomi's latest fitness tracker. The reason why is not as surprising as you think." date: "2018-10-10" modified: "2018-10-10" authors: - name: "Victor Tangermann" job_title: "Senior Editor" link: "https://futurism.com/authors/victor" url: "https://futurism.com/neoscope/fitness-trackers-coffee-cup-pulse" categories: - "Health & Medicine" tags: - "fitness tracker" - "heart rate" - "the digest" - "xiaomi" --- # Fitness Trackers Say This Coffee Cup Has a Pulse. Wait, What? ![]() *\Image: Emily Cho\* ## Toilet Pulse It's the stuff of nightmares: a stuffed animal with a beating heart. After spotting viral posts on social media about users strapping fitness trackers to rolls of toilet paper, Chinese website *Abacus* [tried it with]() a Xiaomi wristband. The surprise result: The fitness tracker detected a heartbeat. The toilet paper's "heart rate" ranged from 59 to 88 beats per minute, according to *Abacus*. A banana and a coffee mug showed similar heartbeats. And yes, one user even got a [pulse from a teddy bear](). https://youtu.be/wwhb3IFX_DM ## Green Light So what the hell is going on? These wonky results are a quirk of how the devices determine your heart rate in the first place. The fitness tracker shines a green light toward your wrist, which blood absorbs because it's red. During beats, more blood passes, and it absorbs more green light, so the tracker can count the pulses and estimate your heart rate. But that tech — also called photoplethysmography — is [easily confused by things that reflect light](). That's not a big concern when the device sits flush against your skin, but it leads to weird results from inanimate objects. ## Heartthrob That doesn't spell the end of the wrist-based fitness tracker — just because the trick works on a banana doesn't mean it's wrong about your pulse. The industry might also move past photoplethysmography. The Apple Watch Series 4 managed to [cram in an EKG scanner](), which measures electrical signals instead of light — a godsend for people with chronic heart conditions. Besides, the less sophisticated fitness trackers out there are mostly meant to do one thing: get you off the damn couch. Do you really want your toilet paper to burn more calories than you do? **Read more:** [Why People Are Putting Fitness Trackers on Toilet Paper in China]() \[*Gizmodo*\] **More on heart rate monitors: [The New Apple Watch Transforms What a “Medical Device” Can Look Like]()** ## Author I've been at Futurism since 2017, where my role has evolved to encompass design, writing, and increasingly editing. I've always been fascinated by space exploration and advanced transportation, which I've leaned into by interviewing luminaries in those fields while closely following the dimensions of policy and regulation that allow next-generation projects to succeed -- or, sometimes, to fail. I'm also keenly interested in the effects of generative AI on society, policies, and democratic institutions, as well as clean energy, physics and biology, and the vagaries of tech leadership. My work for Futurism has been cited by publications including Ars Technica, Gizmodo, PC Magazine, Jalopnik, Fox News, and the New York Post. I spent my childhood living in locations including Manila, the Philippines, and Geneva, Switzerland, attended McGill University, and now live in Toronto, Canada. Before Futurism I worked at AskMen and a small photography studio. In my free time, I'm an avid gardener, foodie, and craft beer lover, as well as a maker of artisanal hot pepper sauces. I have a magnificent dog named Freida. ### Author social links [Bluesky]()