Can your Apple Watch diagnose thyroid issues?

You may already know your Apple Watch can help you hack your treadmill sesh and make your extra-long runs fly by. But another important perk of the device? It could also pick up on healthy symptoms you don’t notice and potentially diagnose your thyroid issues before any doctor. Well, at least that’s what happened to one woman.

When Heather Hendershot’s Apple Watch alerted her that her resting heart rate jumped to a super-rapid 120 beats per minute—much higher than the average of 60 to 100 beats per minute—she was confused, BuzzFeed reports: The 25-year-old lifelong athlete claims to have been healthy her entire life. But when the rate jumped to 160 beats per minute, Hendershot knew something was wrong. The next day, she went to the emergency room and received a surprising diagnosis: She had severe hyperthyroidism.

“To have your heart race and not be aware of it is not normal. It’s interesting that a device told her she was not doing well, and she acted on it.” —Dr. Alan Wynne, endocrinologist

The condition—which occurs when the thyroid gland in your neck produces too much of the hormone thyroxine—can cause symptoms like fatigue, anxiety, rapid heartbeat, and sweating, all of which are easily mistaken for other conditions. Luckily, because Hendershot’s Apple Watch picked up her high heart rate (she didn’t realize it on her own), she was able to catch a potentially life-threatening condition early, before it seriously impacted her health.

“To have your heart race and not be aware of it is not normal,” Alan Wynne, MD, an endocrinologist who treated Hendershot, says. “It’s interesting that a device told her she was not doing well, and she acted on it.”

If Hendershot’s watch didn’t alert her to the increased heart rate, it might have been a long time until she noticed symptoms. “She probably would’ve gone not just days but weeks or months until her thyroid would produce so much hormone day by day that she would start sweating or shaking or having tremors,” Dr. Wynne says.

So, sure, your Apple Watch is great for serving your fitness-centric data. But thanks to its impressively accurate heart-rate monitors, it just might save your life.

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