Already multitool smart devices, Apple Watches added another buzzworthy feature last month: an app to detect sleep apnea . Sleep apnea is a condition that causes a sleeper’s breathing to pause when the muscles of the throat relax too much and the airway collapses. It can contribute to loud snoring, which the sleeper may not even be aware of.

Typically, a partner or roommate picks up on the problem first. The condition has been linked to a host of health problems, primarily wear and tear on the cardiovascular system, including high blood pressure, stroke, heart attack, heart failure and heart rhythm problems such as atrial fibrillation. It’s also been tied to dementia and daytime sleepiness.

And people with sleep apnea are more likely to be involved in traffic accidents, too. Millions of people are thought to have this disrupted breathing condition but have not been diagnosed, and experts say the new app could be a valuable tool to point people to medical care. The sleep apnea notification is available on the latest Series 10 Apple Watches and some older models after a software update.

As with any kind of new technology, however, the sleep apnea feature has limitations and can have unintended consequences, including worse sleep if someone becomes too focused on the information or anxious about the results. “We are seeing this phenomenon called orthosomnia. It’s people that get overly anxious about their sleep data and how they maximize and improve their sleep.

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