How Do Sleep Trackers Work? (And Are They Worth It?)

March 5, 2024

We’ve all had one of those nights: We drift off into a fitful sleep, wake up at two in the morning, and lie awake until five.

After a night like that, dawn comes too early. It’s time to get up and start your day… but you do it drowsily and not at peak performance.

If you experience “one of those nights” more than once in a blue moon, you may be considering a sleep tracker: a wearable device that monitors sleep patterns to identify possible sleep disorders.

But if you’re unfamiliar with wearable tech, you may be asking, “How do sleep trackers work?”

How Do Sleep Trackers Work?

Sleep trackers provide insight into that six-to-eight-hour window in which you’re unconscious and unaware of what’s happening in your body.

Most sleep trackers monitor various aspects of your sleep patterns and behaviors using some combination of motion detection and physiologic signals (like heart rate and breathing patterns). More advanced trackers monitor room temperature or levels of light and noise in the sleeper’s vicinity.

Your tracker can:

  • Understand how many hours of actual sleep you get each night and what your wake windows (periods of non-sleep) look like.
  • Gather information about the time you spend in the primary sleep stages — light sleep, deep sleep, and vivid dreaming (REM) — all crucial to a healthy, rested body and mind.
  • Monitor the consistency of your sleep by observing patterns or inconsistencies in your sleep-wake cycle.

How Useful Is the Data?

Data from your tracker can be quite useful, depending on how you (and your doctor) interpret it.

For example, Fitbits deliver total sleep and wake times, which may be eye-opening (no pun intended): “Wow, even though I go to bed at nine, I only get five hours of sleep every night! Maybe I spend too much time watching Netflix in bed…”

Your Priority Physicians always welcome useful data points. We determine if a lack of sleep may compromise your health and how, together, we can improve it:

  • A look at your breathing patterns can indicate possible sleep disorders, like sleep apnea or too-shallow breathing. If we notice any issues, we may recommend a sleep study, a CPAP machine, or pulse oximetry to see if your blood oxygen levels dip when you sleep.
  • Heart rate can be a key biomarker. It normally dips during sleep, but if we find it doesn’t — or if it increases — it can alert us to underlying dysfunction or perhaps a psychological stressor that needs to be managed.
  • Your sleep stages may yield important metrics, too. Maybe you’re wondering why you always feel like you need a nap, even after seven hours of sleep. Your data may show that you spend six hours of your slumber in light sleep, with less than an hour of deep, restorative sleep.

Quote: How Do Sleep Trackers Work? (And Are They Worth It?)

Pros and Cons of Using Sleep Trackers


Your wearable sleep tech improves your awareness of your sleep.

You track changes and identify patterns that could be helping or hampering how long and how well you sleep. And you may find some surprising connections to your lifestyle patterns (for example, if you find your REM sleep is limited on Friday nights, you may identify Happy Hour with your coworkers as the reason).

When you can correlate your daily behaviors with your sleep quality, you take the first step toward making small but helpful lifestyle adjustments. Your doctor can also review your tracker data to help flag any potential issues.


Not all sleep trackers are 100% accurate. Some may be good at, say, detecting and tracking total sleep time, but are less accurate in differentiating sleep stages. I like to have an honest conversation with my patients to set realistic expectations about the data you’ll get from your tracker.

Also, constant monitoring for “ideal” stats or sleep patterns breeds anxiety. If you worry excessively about achieving “perfect data” — say, if you didn’t spend adequate time in all your sleep stages last night — you stress yourself needlessly. And that, in turn, may negatively impact the quality or length of your sleep.

Want to Track Your Sleep?

Now that you know how sleep trackers work, maybe you’re interested in trying one out. Here are a few recommendations:

  • Remember that sleep trackers are still in their infancy. Even in 2024, the data they provide is an estimation and not 100% accurate. You won’t get a perfect score every night, and there’s no cause for concern if your data is occasionally abnormal.
  • Explore the range of available devices and choose one that’s right for you. Whether that’s Fitbit, WHOOP, Apple Watch, Oura Ring, or another device, each has a unique set of features, with potential advantages and disadvantages. Pick one that:
    • Is comfortable to set and use
    • Is easy to sleep in
    • Monitors the data you’re looking for

I use the Fitbit tracker, which offers basic data about my sleep stages, heart rate variability, and sleep duration. You may care about additional variables, such as skin temperature. Choose the tool that suits your preferences.

Infographic: How Do Sleep Trackers Work? (And Are They Worth It?)

Taking Action

Sleep tracking data is good only when it’s actionable. When you use a sleep tracker, be prepared to make lifestyle changes that may improve your sleep (like opting for soda at next week’s Happy Hour). If you’re unwilling to make adjustments, tracking your data may not be worthwhile.

Need a crash course on “how do sleep trackers work?” Your Priority Physicians would love to have that chat with you… or take a look at your data if you’re already using sleep tech.

Dr. Jacob Brandon

Dr. Jacob Brandon is a board-certified Internal Medicine physician from Fishers, Indiana. Dr. Brandon completed his undergraduate studies at Indiana University-Purdue University in Indianapolis, followed by medical school at Indiana University and Ross University School of Medicine. He completed his internal medicine residency at Ascension St. Vincent hospital in Indianapolis, serving as Chief Resident his final year before then joining a traditional primary care practice in Indianapolis. Throughout his education and career, Dr. Brandon has been fascinated by the ever-evolving landscape of healthcare technology. He has a particular interest in exploring and implementing innovative applications of AI and machine learning to improve the health outcomes of his patients. By leveraging these cutting-edge tools, he strives to stay at the forefront of medical advancements, ensuring that his patients receive the most comprehensive and effective care possible. Beyond his professional endeavors, Dr. Brandon feels incredibly blessed to have a supportive and loving family. He and his wife, Tessa, are raising two wonderful children, Finn and Noa. Their children bring immeasurable joy to their lives and serve as a constant reminder of the importance of health and well-being.

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