Top CEOs are obsessed with this $300 Oura Ring that tracks sleep and health metrics

Fitness trackers have become an essential accessory for high performers. The global wearable technology market size crested over $61 billion in 2022 and is expected to grow 14.6% between 2023 and 2030. Of all the offerings out there, one device appears repeatedly on the fingers of C-suite execs: the Oura Ring. Meta's Mark Zuckerberg is a fan, so are Square's chief executive Jack Dorsey and Casper CEO Neil Parik.

In 2013, Oura entered the market with the promise of better sleep data. The company educated wellness-minded masses on the importance of rest at a time when other wearables emphasized metrics such as steps, calories, and heart rate. This message continues to resonate: A decade after the tech’s release, over two million Oura Rings (and counting) have been sold.

“We started in sleep, which was a really conscious decision,” says Oura CEO Tom Hale, who joined the company in 2022. “Sleep is something that everybody does at least once a day, yet no one really knew what was going on with them while they were asleep,” he says. While daytime fitness data amounted to heart fluctuations due to stress, exercise, and more, sleep offered an opportunity for a new kind of experiment. What could be discovered about your well-being during those mysterious eight hours of sleep? And, eventually, how could you change your daytime habits to coax yourself into a better night of rest?

How the Oura Ring works

Oura sleep metrics, which include buzzwords such as latency (or the amount of time it takes you to fall asleep) and restfulness (which tracks your wakeups and nighttime movements), offered new avenues for thinking about sleep health. Hale himself remembers the sudden availability of his sleep data as an instant life boost. “I had kids and then had a very demanding career. I would drink coffee in the morning and then drink wine at the end of the day—that was how I managed,” he says. Wearing the Oura made him realize that skimping on sleep affected everything, including how he showed up at the gym, at work, and in his personal life. “That change for me was transformative. It's actually what got me into the company,” he says.

Nowadays, Oura has expanded its offerings to include many pillars of health and well-being, including fitness, cycle tracking, stress, and more. For many users, including high-powered C-suite, wearing their Oura Ring amounts to a holistic map of their well-being.

CEOs say Oura helps them perform better

Lindsay McCormick, founder and CEO of oral health company Bite, relies on the device to assess her energy levels. “Energy management is so important as a CEO. With my Oura Ring, I can see when I didn’t sleep well, when I’m not getting enough exercise when I’m stressed so I know when I can push harder and when I need to take a break,” she says.

McCormick, who’s used the device for about two years, even goes as far as planning her days around her Readiness Score, a number from one to one hundred that represents how prepared you are for the day based on your lowest overnight heart rate, how much activity you did the day before, your body temp, heart rate variability (HRV), and more. “I check my Oura metrics every morning before checking our company dashboards. If my sleep quality and readiness score starts trending down, which happens during periods of sprints or stress, I structure my day so the important tasks are in the morning and early afternoon to make sure nothing slips through the cracks as my energy dips,” says McCormick.

Over time, the ring has even convinced her to give up her night owl tendencies in favor of an early bedtime and a productive morning routine. “I’ve seen my sleep score, readiness score, and stress levels all improve, and the quality of my work is better,” she says.

Sleep has also been the principal focus for Carly Kremer, founder and CEO of Beekeeper’s Naturals. “Prior to using the Oura Ring, I didn’t know what specific conditions I needed to create to have a restful night of sleep,” she says. “Tracking my sleep has been hugely informative and led me to significantly refine my bedtime routine.” She says that after seeing how interacting with technology negatively affected her sleep, she now tries to put her phone away before 7 p.m. and wears blue light-blocking glasses if she has to be on her devices after dark.

She’s also been more mindful of how to use light to wake up and wind down her brain. In the mornings, she goes outside to soak up a bit of sunshine. At night, she turns down the lights in her home to send the message to her brain that sleep is near.

Oura ring during sleep.

What’s Next for Oura

While it’s fair to say that the word “Oura” and the word “sleep” have practically become synonymous in the wellness community, the company is committed to pushing other facets of health to the forefront. For example, the company’s foray into reproductive health last year has allowed users to learn more about how to care for themselves in tandem with their menstrual cycle. The Oura Ring tracks your temperature and predicts when you may start your period or begin ovulation.

The company has also made strides in illness tracking and plans to continue focusing on this in the future. “We were one of the first wearables to have really, really good, accurate temperature measurement,” says Hale. Oura uses spikes in body temperature to forecast that you may be falling ill (though it’s not considered a medical device).

“An individual’s body temperature typically changes by about 1 °C (1.8 °F)  between its highest and lowest points each day,” reads the company website. Temperatures that fall outside of that range may be an indication that something is challenging your body and immune system. “Now we'll warn you that you're getting sick, and you might want to go into what we call ‘rest mode,” says Hale. Rest mode indicates a time period where you’re actively choosing to recover rather than head out for that run or spend a 10-hour day at the office.

More on sleep and stress:

• Your ultimate guide to getting a good night's sleep

• I took Headspace’s guided sleep course. Here are the 5 habits I learned

• Do men really sleep better than women? Experts explain

• How stress is making your biological age older than it actually is

This story was originally featured on Fortune.com