Apple Watch's heart rate sensors alert man to undiagnosed atrial fibrillation

An Apple Watch owner in England was recently rescued by a watchOS alert that his heart rate had suddenly spiked, even though he otherwise felt fine.

Kevin Pearson was already at a hospital accompanying his father to an appointment, when his Watch warned him that his heart had surged to 161 beats per minute, The Independent said on Monday. That rate is higher than what many athletes reach in the middle of intense exercise.

Despite not feeling any symptoms of a heart attack, Pearson said he followed the Watch's instructions and sat down, keeping an eye on his heart rate for several minutes. It ebbed and flowed, down from its original peak but still ranging between 79 and 135 beats per minute.

Pearson was concerned that the Watch was inaccurate, but asked doctors to check regardless. They discovered that he was suffering from atrial fibrillation, and directed him to specialists at a bigger hospital, where the seriousness of the situation was reconfirmed.

He wrote Apple CEO Tim Cook in thanks, and as of today he's set his Watch to alert him to spikes over 120 beats per minute.

"I've used my Apple Watch for calendar events, to complete its targets by exercising, and using it to lose weight," Pearson remarked. "The heart rate wasn't really of any particular value, and I didn't even know it could alert you if it was too high."

Though the accuracy of the Watch's heart rate sensors isn't infallible — it can sometimes fluctuate widely, including during exercise — Apple has made a particular point of emphasizing health uses. The company is even running the Apple Heart Study in conjunction with Stanford Medicine, one benefit being people who receive alerts similar to Pearson's can be put in touch with professionals and even sent an EKG patch.

36 Comments

cjk91108 14 Years · 9 comments

About 6 years ago

Good story and great feature but your HR info is a bit off. As an amateur bicycle racer, my max HR is above that and I’m low for my peers. So to say that 161 is higher than most during intense activity may be a disservice. Max has to do with training, age and size and one should never assume from another’s max or working HR.

frantisek 11 Years · 760 comments

this one of the ways where Apple put its bets for future. Phone becomes commodity but helping people being more healthy, can bring number of valuable customers.It will not be as easy to replicate as doing "we can do it as well" phone.. At leas not by cheep knock offs.

Soli 9 Years · 9981 comments

cjk91108 said:

Good story and great feature but your HR info is a bit off. As an amateur bicycle racer, my max HR is above that and I’m low for my peers. So to say that 161 is higher than most during intense activity may be a disservice. Max has to do with training, age and size and one should never assume from another’s max or working HR.

That sentence in the article could be better, but it's not wrong. The "rate is higher than what many athletes reach in the middle of intense exercise," with the the use of many giving no specific number (not even a ballpark figure) and athletes spanning any age or sport. Golfers are athletes but I doubt their heart rate spikes at any age, and an octogenarian running a marathon are athletes who's peak max shouldn't be over 140±11 using the 220 minus age formula.

My heart rate peaks at just under 170 when my workout is intense. I know this because of the Apple Watch, but I also don't need my Watch to tell me I'm at my max as I can feel my pulse rate through every part of my body (without even using my fingers to count). Of course, I wear my Watch because one day warn me about an atypical situation. I also wear my Watch to bed and use the app Sleep Watch. On days that I burn 475+ Active Calories in a single session I have 6% better sleep that night.