How much should you trust your fitness tracker?

SALT LAKE CITY — From smartwatches to smart rings, wearable devices can collect vast amounts of information about daily activity, sleep and heart rate.

But how much can fitness trackers actually tell us about our health, and what might they miss?

For Courtney Stowe, tracking health data became personal after her husband experienced heart failure.

"After he had his health scare, I just started doing it," she said. "It gives you great peace of mind."

She's far from alone. Nearly 60% of U.S. adults now own at least one wearable or connected health device, like Apple Watches or Oura Rings. These gadgets can help people move more — a research review published in The Lancet Digital Health found activity trackers helped people take roughly 1,800 extra steps a day.

But understanding those numbers requires context. A 2026 review of Apple Watch studies found heart-rate readings were generally close to reference measurements, while calorie estimates were often off.

"You shouldn't ever just assume that the data you're getting from your tracker is completely accurate," said Dr. Clark Madsen, an Intermountain Health sports medicine physician.

According to Madsen, basic physical movement can easily throw off a sensor's accuracy, meaning an unexpected spike or dip on your screen doesn't necessarily mean something's wrong.

"One of the biggest issues we have is people will come in worried about one little blip instead of looking at the bigger trend," he said.

Madsen noted that he sees patients become anxious over the numbers. He encourages users to consider device information along with how they actually feel physically, rather than focusing exclusively on a screen.

"We shouldn't rely on that data to tell us that everything's okay when it's only measuring small data points and not giving us the full picture," Madsen said.

Madsen recommends following up with a medical provider about repeated unusual readings or a health alert.

"It shouldn't replace a provider, and it shouldn't replace your own general idea of how you're doing," he said.

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