When the Apple Watch was first announced in late 2014, the general public’s reaction was, basically, “Why?” Why do I need a mini phone on my wrist when my phone is in my pocket? Why do I need to pay $350 (or more) for a step tracker when my Fitbit costs less than a third of that? Now, five years later, the answer is becoming clear: Thanks to rapid advances in technology, the Apple Watch and other wearable fitness trackers aren’t so much mini smartphones as they are personalized health-care devices, arming users with easy-to-digest snapshots of their activity and recovery data in order to optimize their health and wellness. And in 2020, new gadgets, features, and health-care applications for this tech will reach more people than ever before.

The smart wearables market is booming—by 2022, it’s estimated to be worth $27 billion, which is double its 2018 value. Market analysis firm CCS Insight projects that 85 million smartwatches will be sold globally in 2019, with the Apple Watch accounting for approximately half of all smartwatch units sold between January and June (the Chinese brand iMoo, Samsung, and Fitbit are second, third, and fourth in sales). In November, Google’s parent company Alphabet threw its weight behind Fitbit, purchasing the step-tracking pioneer for $7.35 per share in cash (the equivalent of about $2.1 billion). That same month, the sleep and activity tracker Whoop secured an additional $55 million in funding for “consumer acquisition, membership services, and product development” in 2020 and beyond, according to a press release.

The wearables on the market today have leveled up from the early days (you could say they’re the Charizards to generation one’s Charmanders). In addition to tracking your steps, they also clock your heart rate, sleep patterns, stress levels, menstrual cycle and fertility windows, and noise levels (the last two being new features that Apple rolled out in September of 2019). “We’ve advanced from simply counting steps to bringing health information once only available from a lab or clinical environment—like heart rate and sleep tracking—directly to consumers’ wrists,” says Shelten Yuen, Fitbit’s VP of Research.

“We’ve advanced from simply counting steps to bringing health information once only available from a lab or clinical environment directly to consumers’ wrists.” —Shelten Yuen, Fitbit’s VP of Research

Whoop founder and CEO Will Ahmed believes the explosion of personal health trackers has coincided with a growing appreciation for a more holistic approach to health care. Your overall health, Americans are coming to understand, is the sum of all the small choices you make each day—what you eat, how much you move, how much you sleep, etc. “Our point of view on understanding your body is that you need to really balance the strain and recovery in your life,” says Ahmed. The applications of this are broad, he says: “If you’re an athlete and you’re overtraining, you’re putting a lot of strain on your body day after day, you can burn out or get injured.” But it’s the same if you work a high-stress job, are traveling a lot, or are chronically undersleeping: Finding ways to balance your stress and recovery is key to better health. “Once you get used to measuring everything about your body, you can start to understand how to change all these different things in your life for the positive,” says Ahmed.

“We believe the more a user understands about their personal health, the more empowered they are to make meaningful behavior changes,” says Yuen. “But it’s not just about giving people more information, it’s about helping them know what to do with it.” For Fitbit, this means a feature called Reminders to Move, which prompts users to take 250 steps each hour. And on December 3, as part of a suite of new features, Fitbit announced that Premium subscribers will receive a personal wellness report of health-boosting recommendations created using your data and “developed in consultation with leading medical professionals from institutions like UCLA and UCSF.”

Alexandra Zatarain, co-founder of “sleep fitness company” Eight Sleep, similarly believes that the data her products gather (including Eight’s marquee product: a smart mattress that dynamically warms or cools based on your body temperature) are only as useful as the healthy changes they help engender. To this end, in January of 2020, Eight will launch a new integration with Google Fit and Apple Health that combines the sleep data Eight collects with the health and activity data your other devices capture to give a more accurate picture of your overall health. In the coming year, Zatarain says Eight also has plans to introduce new tools that allow users to input details about their daily habits (such as how much coffee they drink or when they exercise).

One metric that wearables makers are putting increased emphasis on is heart rate variability, which is calculated by looking at the amount of time between consecutive heartbeats. “What you want is to be in more of a flow state where there’s more variation between each beat. The higher the heart rate variability, the better or less stressed you are,” says Harpreet Rai, CEO of Oura (a sleep and activity tracking ring that was named one of CES’s “most innovative products” in 2016 and made waves in 2018 after Prince Harry was spotted wearing one). Oura packages heart variability with your other biometric data (including your body temperature, resting heart rate, sleep balance, and activity balance) from the previous day and night in order to give users a “Readiness” score each day.

Robin Berzin, MD, founder and CEO of the functional medicine practice Parsley Health, says that in recent years, she’s seen more and more of her patients using wearable devices and smartphone apps to track their personal health data. “When patients actually see data that illustrates how destructive behaviors impact them physically, it can provide additional motivation to more proactively manage their health—such as incorporating appropriate physical activity, getting to bed earlier, being more open to using stress-reduction techniques such as meditation,” Dr. Berzin says.

“As a health-care practitioner, a patient’s personal data can often help to paint a broader picture of a patient’s lifestyle…but it’s important to remember that these devices are still in their early days.” —Robin Berzin, MD

Dr. Berzin adds an important caveat, however: “As a health-care practitioner, a patient’s personal data can often help to paint a broader picture of a patient’s lifestyle…but it’s important to remember that these devices are still in their early days. The accuracy and validity of the data still needs to be strengthened before these trackers can be used to guide medical advice.”

Michael Snyder, PhD, director of the Center for Genomics and Personalized Medicine at Stanford University, is working to gather such research, including how wearables can be used as diagnostic tools for illness and disease. In 2017, Dr. Snyder published a study demonstrating how wearables can be used to indicate the onset of infection (a participant in the study himself, he used the data to discover that he had contracted Lyme disease, which was verified by a doctor). Now, Dr. Snyder and his team at Snyder Labs have created an algorithm that synthesizes wearable sensor data to predict illness, and in 2020, they’ll be rolling out a bigger study to see how well smartwatch data can detect when people are getting sick.

The big guys are investigating the health-care implications of their products as well. “Wearables offer significant opportunities for health care, and we’re exploring ways our devices and algorithms can help detect conditions and then also play a role in the management of those conditions moving forward,” says Yuen. “For example, we’re making early progress in the areas of sleep apnea and [atrial fibrillation], which are two of the most common health conditions worldwide.”

After seeing early success with its Heart Study, Apple announced three new multi-year longitudinal studies along with the launch of its Research app in mid November. With the Heart and Movement, Women’s Health, and Hearing Studies (which are now open for enrollment and expected to gain traction in 2020), Apple aims to leverage the ubiquity of its products to provide research partners (such as the World Health Organization) with user data to inform potential medical discoveries that could improve health care for all.

As Rai sees it, the further proliferation of health tech comes down to three key factors: “If you make it more accurate, if you can make it more meaningful, and if you make it more convenient, you’re going to see greater demand and better consumer adoption,” he says. With the cluster of announcements and releases in the final months of 2019 checking all three boxes, the writing’s on the wall for wearables in 2020: Next-level tech will be able to help even more consumers recharge their health.

But wait, there’s more! Click here to read the rest of our 2020 Wellness Trends predictions.