With the advent of wearable biometric tech like smartwatches, consumer-based sleep analysis technologies are gaining in popularity, as a bigger crowd moves to hack their bodies’ functions in our never-ending quest for wellness monitoring, the Wall Street Journal reports. Until recently, the only way to thoroughly assess your shut-eye was to be wired up and observed by doctors in a clinical setting. But along with the wearable activity-tracker revolution came a variety of sleep-monitoring products that promise to optimize your sleep cycle outside of a medical setting.

In a sign of the times, the sleep-tech business is now exploding: It’s projected to be worth about 3x what it was in 2018, and is expected to grow into a USD 27 bn industry by 2025, according to Global Market Insights.

Part of the hype is an increased awareness of the effect of sleep on wellbeing: Sleep disruptions or deprivations can cause a variety of problems, ranging from stress and irritability, to errors in judgement, to headaches and other physical pains. But it’s not just about how much sleep you’re getting, the quality matters too. One study that followed the sleeping patterns of more than 43k subjects for over six years found that those classified as “evening types” — those whose sleep cycles left them more or less constantly jet lagged — experienced a higher risk of cardiovascular disease, and had a 10% increased likelihood of dying.

And covid-19 is exacerbating the problem: While sleep problems are not new, a rising trend of what some sleep experts call “coronasomnia” — a portmanteau denoting the interference in sleep patterns caused by the pandemic — has manifested over the past year among around four in ten people. Routines went out the window, with many reporting “feeling perpetually in sleep debt” and experiencing increased anxiety.

Cue sleep trackers as a solution for those restless nights: These devices claim to help people make informed decisions about how to optimize their sleep cycles by determining bedtime behavioural changes and recording patterns throughout their sleep.

How do sleep trackers work? They collect data points throughout the night and translate this information into a sleep score. Many sleep-tracking technologies use accelerometers to track nocturnal movement and present sleep-stage data, with less movement equated to deeper sleep. They can also listen to your heart rate, trace your breathing patterns, and keep tabs on blood oxygen levels. Some of them even record sleep talking, while others monitor air quality.

CAVEAT- Sleep trackers are not medical devices: Sleep trackers often measure inactivity as a surrogate data point to guesstimate how much you’re actually sleeping. In other words, a wearer who is wide awake but also lying still could get an imprecise sleep summary the next day. Research has found that compared to polysomnography tests — which experts use to diagnose sleep disorders — these technologies are only accurate 78% of the time when identifying sleep versus wakefulness, with their accuracy dropping more than twofold when estimating how long it took participants to fall asleep. Still, sleep-monitoring tech can definitely be useful in helping recognize whether sleep disruptions are occurring, prompting users make environmental changes that could give them better rest.

In case you’re interested, here are the go-to options: Many are smart wearable trackers that users strap to their wrists like the Apple Watch, and Fitbit and Garmin Fēnix’s gadgets, which use the motion-sensing tech inside the watch to detect even minor movements. Wireless sleep-enhancing headbands are another type of wearable tracker that monitor brain activity and use advanced algorithms to detect sleep patterns, promising to boost periods of deep sleep with a meditative and calming soundscape — Muse S and Dreem are just a few of the options available. Other devices can clip on your pillow or sit on your nightstand, like Google’s next-generation Nest Hub — which measures nighttime movements and breathing through sensor strips — or sleep-tracking mats such as Withings Sleep Mat that slip easily under a mattress. Also on the contactless front: sleep-monitoring apps, including Sleep Cycle, SleepScore and Sleep++.