Amazon Halo Sleep Score: Getting an Accurate View of How Your Sleep Affects Your Health

William C. Dement, M.D., Ph.D., the father of modern sleep medicine, said “Sleep is an essential part of life — but more important, sleep is a gift” [source: “The Promise of Sleep: A Pioneer in Sleep Medicine Explores the Vital Connection Between Health, Happiness, and a Good Night’s Sleep”]. At Amazon Halo, we agree! When it comes to connecting your habits to how you feel, sleep is just as important to understand as your activity or nutrition. That’s why Halo goes beyond tracking how long you’re asleep to help you understand your sleep patterns, like how long you’re in each sleep stage and how many times you wake up in the night. These data points help to form your Halo Sleep score, which is designed to help you easily track the quantity and quality of your sleep so that you can make informed choices to improve your rest and feel your best throughout the day.

Why is sleep important?
According to the Nature and Science of Sleep Journal, obtaining sleep that is of sufficient quantity and quality is truly a pillar of health. Without it, there can be serious consequences that touch on nearly every aspect of our mental and physical wellbeing. Lack of good sleep can contribute to a number of health issues including:

• Excessive daytime sleepiness or fatigue
• Poor concentration or attention
• Short-term memory problems
• Mistakes and accidents
• Anxiety, depression, and irritability
• Increased pain
• Feeling unwell
• Weight gain

Beyond getting your recommended 7- 9 hours of sleep per night (based on research by the Academy of American Sleep Medicine), the quality of your sleep also matters. The factors that influence this may vary from one person to the next, but most people will find sleep to be more restorative and satisfying when it occurs overnight in a regular pattern with optimized efficiency. Sleep efficiency is defined by the time it takes you to fall asleep, and the number of times you wake up during the night. The less time and disturbances, the higher your efficiency.

How does Halo measure your sleep?
Now that we know why sleep is important, we can look deeper at some of the key factors used to measure the quality of your sleep. These are measured using the sensors on your Halo band that gather heart-rate and motion data:

• Total time asleep
• Total time in bed (awake or asleep)
• Time to fall asleep
• Frequency and duration of sleep disturbances
• Total time in deep sleep
• Total time in REM sleep

Based on these factors, Halo is able to detect and measure your primary sleep session for the day to calculate a sleep score between 0- 100. This Sleep score makes it easy to see how your sleep quality improves (or decreases) over time.

• 85- 100: Great sleep quality
• 70–85: Good sleep quality
• < 70: Fair/Poor sleep quality

Visit the Sleep page within the Halo app to dive into the sub-factors that go into your sleep score and discover where you have the greatest opportunity to improve. You can also see the weekly or monthly trend for your sleep score and key factors to continuously track your sleep.

What are sleep stages?
There are three stages of sleep — REM, light, and deep — each stage is responsible for a different function in your body’s recovery and restoration.

With the Halo app you can see a detailed breakdown of your sleep stages through an interactive chart called a hypnogram.

The hypnogram shows how much time you spend in each stage during the night. Deep sleep typically accounts for less than 20% of your total time asleep, and happens more frequently in the first half of your sleep. The more deep sleep we have, the more rested we may feel. REM sleep typically accounts for 20 to 25% of total time asleep and increases with each sleep cycle, often accounting for more time in the last third of your sleep. Finally, light sleep makes up the rest of our sleep stages.

To get more information about each sleep stage, you can tap any point of the interactive hypnogram on the sleep domain page which will show you the time period, duration, and stage of sleep.

Sleep accuracy
Whether it is related to our sleep data, or any of our other health and wellness tools, accuracy is a key focus for the Halo team. We developed the Halo Sleep score and validated sleep algorithms conducting sleep studies in both a sleep laboratory and at home. Sleep data was collected using sensors on the Halo band in addition to a full polysomnography (PSG) recording that collects different body signals measured during sleep. Each PSG recording was scored by three different technicians and a sleep doctor to generate a ground truth sleep report and a sleep quality score (1–100). The scored report was compared to the data Halo collected to measure the performance of our sleep algorithm. The algorithm was validated on data from more than 150 sleep sessions, on more than 100 unique voluntary participants. The Halo team regularly conducts sleep studies to measure and improve algorithm accuracy.

Here are some tips to ensure that Halo tracks your sleep as accurately as possible:

• Double check your Band fit — To capture the most accurate sleep data, we recommend wearing your device just above your wrist, and snug enough so that the sensors on the bottom of your band have direct contact with your skin at all times.
• Make sure sleep is sleep — There are some situations, like if you’re lying down watching a movie or reading a book before bed, where Halo may think you’ve fallen asleep. If you review your data and think this has happened, you can now edit last night’s sleep by tapping on the pencil above the hypnogram on the sleep page and trimming the start or end times to be more accurate.

How can Halo help you improve your sleep?
Halo can help you identify patterns to connect your routines to the quality of your sleep. For example, you might notice an increase in your sleep quality after starting a bedtime meditation routine. Tap Discover within the Halo app to explore a variety of expert-backed programs designed to help you sleep better, including a series of bedtime meditation or relaxing sounds (in partnership with Relax Melodies and Headspace), or helpful tips from the Halo team that you can use to improve your sleep habits.

We always strive toward achieving the highest possible standard of accuracy and experience for our customers. As always, we are inspired by your feedback, so keep it coming! We look forward to hearing what you think about the Halo sleep score, as well as the Halo recommendations and strategies that help you rest your best.

Be well.