I don’t know if you remember, but there was a time when we were all crazy about wearables. Fitbit was in its heyday and it made fitness tracking super popular. It was also around when sleep tracking started picking up. 

These days, the hype has died down a bit but sleep tracking is still popular especially for people who want to boost their productivity or are worried they are not getting good quality sleep. More devices than ever, from smartwatches to smartphones and even smart mattress pads, can track your sleep. 

But are sleep trackers really helpful? Can you improve your sleep quality by monitoring your total sleep time, sleep phases, sleep latency, sleep efficiency and other metrics? Or are all these just vanity metrics that don't really help us much? Are they even accurate? 

Ok, enough with the questions. Here’s the lowdown on sleep tracking, including its benefits and limitations. 

What Do Sleep Trackers Track?

Sleep tracking features and capability vary among different sleep trackers. But generally, they promise to track the quality and quantity of your sleep, with the aim of using this data to help you sleep better. 

Here are the most common things sleep trackers track. 

• Sleep duration — How long you have slept. Trackers have sensors to detect whether you are active or not, so they can sense when you go to sleep and when you wake up. 
• Sleep disturbances — The motion sensors in sleep trackers can also capture nighttime awakenings such as when you wake up to use the bathroom or if you wake up from a bad dream. 
• Sleep latency — How long it takes for you to sleep once you get into bed. Your sleep latency can tell you a lot about your sleep quality. If you fall asleep after just a couple of minutes, you are probably sleep-deprived. If you take longer than 20-30 minutes, that could be a sign of insomnia. 
• Sleep stages/phases — Some sleep trackers can also detect which sleep stage you are in and measure how much time you spend in each stage. Data about your sleep phases can tell a lot about the quality of your sleep. Tip: Trackers with a heart rate sensor offer more accurate sleep stages measurements. 

Other metrics measured by sleep trackers include heart rate, heart rate variability (HRV), respiratory rate, blood oxygen level and environmental disturbances like light and noise. 

Are Sleep Trackers Accurate?

Obviously, a sleep tracker cannot match the accuracy of a sleep study, also known as a polysomnography. During a sleep study, which usually happens at a clinic, a specialist tracks your brain waves, blood oxygen, heart rate, breathing and other metrics.

The equipment at a clinic will be far more precise and accurate compared to the tiny sensors in your wrist smartwatch. 

One study compared sleep trackers to a polysomnography and found that trackers are accurate 78% of the time. That sounds pretty good, right? But there’s a catch. This was only when they were tracking wakefulness and sleep.  

That’s like one of the easiest tasks for the trackers using built-in motion sensors. 

However, they performed terribly (38% accuracy) when measuring how long it took for people to fall asleep (sleep latency). That’s because people generally don't move around until they doze off. There’s a period where you get still even though you are still awake. 

Sleep trackers also perform so-so when tracking sleep stages and sleep duration, usually getting things right only 50% of the time. Sleep trackers with a heart rate monitor are a bit more accurate, but many still underestimate or overestimate certain metrics.   

Do Sleep Trackers Help or Hurt Your Sleep?

On the surface, sleep trackers seem like an essential tool for people who want to improve their sleep quality. But oftentimes, they end up not helping at all. 

The biggest issue with sleep trackers is their low to medium level accuracy. Most of the data you are getting from the sleep tracker is not accurate. So relying too much on it to determine and improve your sleep quality is not a good idea. 

This is particularly the case for people already experiencing sleep problems like insomnia, which is a lot of us nowadays. A sleep tracker may be even more inaccurate because it can’t detect all the time you spend in bed laying still trying to sleep. A sleep tracker will not give you an accurate picture or diagnosis of your sleep problems. 

Sleep trackers can also create phantom problems. They have been known to underestimate sleep duration. This can lead to sleep anxiety, a serious problem that can worsen your sleep quality. 

If you are just interested in your sleep data, a sleep tracker is fine. But if you become obsessed with the metrics, you are creating harmful anxiety around sleep. 

What To Do Instead of Using A Sleep Tracker

If you suspect you are having serious sleep problems, the solution is not to get a sleep tracker but to see a sleep specialist. They will perform a sleep study where they can more accurately measure sleep duration, sleep stages and other important metrics. 

If you just want to improve your sleep quality, you don't need a sleep tracker for that. If they were highly accurate, then maybe they could be helpful. But the data you get likely doesn't reflect your sleep quality. If anything, it will just make you more anxious about sleeping, which makes it harder to sleep. 

To get better sleep, there is plenty you can do. Have a regular sleep routine that gives you 7-9 hours of sleep, don’t use your phone in bed, avoid caffeine and alcohol in the afternoon or evening, and so on. 

It also helps to create a sleep-friendly bedroom. Keep it cool, quiet and dark. Your bed matters a great deal as well. Invest in good sheets like our Jax Sheets, get a high quality mattress that has adequate support, get a good pillow and use a breathable comforter. 

Don’t focus so much on specific metrics. You will know when you have slept well. You will feel rested, energized and you will be in a good mood. 

You will also know when something is off with your sleep. You will be moody, irritable, tired and have difficulty focusing. Instead of creating more anxiety with a sleep tracker, simply try to sleep better and longer. 

If you have persistent poor quality sleep, it might be a sign of a sleep disorder. This is where going in for a sleep study will help. Problems like sleep apnea and chronic insomnia may require medical treatment.