Eversleep 2 - by 

Darius Zoroufy, M.D. 



I tested the EverSleep 2 sleep tracking and management system.   

Over the last few years patients are asking more and more about the data their wearable devices tell them about their sleep.  The majority of these devices rely on an accelerometer to detect movement.  To understand how a fitness tracker can detect sleep, first we need to understand how it detects activity like counting your steps each day.  Fitness trackers use a very small system of capacitors to detect acceleration. Remember that acceleration is not velocity or speed.  That’s why your FitBit will not count any movement as you sit in seat 26E (middle seat) even though you are flying at 583 mph in a 737.    

In case your physics is a bit rusty, remember that acceleration is the change in velocity occurring in a specific time.  a = Δv / Δt  So when your wrist changes speed during your stride, the acceleration is detected and from that wrist movement, body movement is extrapolated.  Of course, your wrist may undergo acceleration and the accelerometer signals may be decoded incorrectly.  For example, I drove for 2 hours on a very bumpy road a couple of years ago. As my car bounced along, so did my wrist.  At the end of the drive my Fitbit had counted almost 4000 steps, even though I had only been sitting.   

(Here is a great demonstration of activity detected by a wrist accelerometer.)   

(If you really want to know how accelerometers work, check this out.

Even though fitness and activity trackers are not perfectly accurate, they can provide helpful information to guide our behaviors.  For example, my outdoor thermometer may be 3 or 4 degrees off, but it is accurate enough to let me know if I should wear a jacket.   

By 2016 more than 100 million fitness and activity trackers were made per year, and the market continues to grow.  The devices are getting better and adding more functions to distinguish themselves.   

Sleep occurs when cortex of the brain changes state and the electrical activity of the cortical cells begins to slow.  Sleep stages are measured by using an electroencephalogram in a controlled environment by a trained EEG or sleep technologist.  Electrodes are attached to the scalp to measure microvolt signals.  These recordings are interpreted using specialized equipment that costs hundreds of thousands of dollars.  Interpreting the data correctly requires years of training and experience 

Fitness and activity trackers shortcut this process by measuring sleep using the same accelerometer to estimate how deeply asleep you are.  These devices use record movements in a manner similar to a validated clinical sleep testing process called actigraphy.  Estimating sleep by recording wrist movement might seem wildly inaccurate, until you think about how your hands move while you are awake.  Beginning in infancy humans move their hands continuously as the output of their cognition and as their means for interacting with the world.  As we become drowsy and fall asleep, our sensory processing and cognitive activity decrease and consequently so do our hand movements.  The recorded wrist movements from an activity tracker can be interpreted to estimate sleep stages.  Fitness trackers that also measure heart rate can include that data to improve the accuracy of sleep stage determination.   

Recently, I bought an EverSleep 2 device, because it had features, I have not seen in other wearable devices.  EverSleep 2 was successfully crowdsource funded by IndieGoGo in 2017, receiving 224% of their target funding.  Since then EverSleep has become increasingly popular due to its many features that record physiological data and then present it in an organized, user-friendly app that provides interpretations of the data that are meaningful.  The app has additional features not seen in many other trackers:  it provides personalized sleep advice to modify behaviors to improve sleep quality.   

EverSleep 2 presents data in the app in an easily understood "Overview” display that give the user data about their sleep plotted on a graph that shows their specific numbers in relation to normal values.   


Under the “Details” tab the EverSleep app graphs the oxygen saturation, heart rate, motion, and sleep.  You can expand the graph to get a closer look at specific parts of the night.  They have even added a feature that is very helpful to sleep specialists:  the numerical and graphical data can be exported as a PDF to review with your physician.  The format of the PDF report is similar to the reports generated by clinical oximetry recording devices, so a physician will find it easy to integrate the data into a clinical assessment.   

Perhaps the most useful aspect of EverSleep 2 is the “Coaching” tab.  This feature takes the data from the nightly recordings and provides comments that reinforce positive data such as  

“Your profile says that you sometimes wake up during the night, but not last night!” 

“Sweet! CPAP seems to be working for you!” 

Each message has the option to “Read More” for more detailed information.   

The Coaching tab also provides specific comments that integrate the recorded data with the user-supplied data to provide personalized advice.   



Recording oxygen data is unusual for a consumer sleep tracker, but it is a very helpful feature.  EverSleep is careful to note that this is not a medical device, so it has not been validated to diagnose disorders or to direct treatment.  Nevertheless, the oximetry data can draw attention to potential areas of concern.  For example, if EverSleep detects episodes of low oxygen, it could suggest that sleep apnea or other respiratory disorders could be contributing to poor sleep.  If the person is already using CPAP or some other treatment for sleep apnea, EverSleep can confirm how well sleep apnea is controlled.   

Eversleep also records and detects snoring which could be a sign of sleep apnea, which can interfere with sleep quality and can increase the risk of cardiovascular disease.  In many cases, a person has no idea that they have sleep apnea.  Although EverSleep does not diagnose sleep apnea, it can detect snoring and oxygen changes that may suggest that further testing for sleep apnea is warranted.   

EverSleep 2 is extremely lightweight;  I barely felt that I was wearing it.  Since it is not an exercise tracker, it does not have to be rugged and waterproof.  The tracker itself is shaped like a watch with a thin band that hold it on the wrist.  The oxygen sensor probe extends from the tracker and wraps around a finger.  EverSleep suggests the user secure the sensor with a small piece of tape.  Once the tracker and sensor are in place and the app has been started it is easy to forget that it is there.  In the morning, simply remove the tracker and stop the recording.   

EverSleep 2 is currently for sale for $199, which purchases the sleep tracker that records sleep quality and sleep interruptions, sleep duration, movement, and snoring, as well as the oximeter which records oxygen levels and heart rate.  It also includes the app which interprets the data and provides meaningful, personalized assessments and recommendations.  I believe that EverSleep 2 will be a valuable tool to help many people improve their sleep quality and their health.   

 Check out EverSleep on Twitter: @GetEverSleep

Zinus Pressure Relief Memory Foam Cloud Mattress Review

In sleep medicine clinic one of the more common and easily solvable problems interfering with good sleep is an old, bowing, uncomfortable bed.  After spending thousands of dollars at a department store mattress department or a bed store in a strip mall, people are reluctant to discard their investment and spend thousands more with a high pressure salesperson.  Buying a mattress has been about as fun as buying a used car.  They are pleasantly surprised when I tell them that buying a mattress in 2018 is much easier and much less expensive than it has been in the past.   After reviewing and recommending mattresses for patients and Twitter followers it was finally time to upgrade my own bed.  Our 10-year-old Spring Air pillow top mattress has served us well.  But now even with a memory foam mattress topper Holly and I have been feeling stiff in the morning.  It was time to follow my own advice and buy a comfortable mattress at a good price.  The advice I offer to my patients is to research the available products online by first checking Consumer Reports for their comprehensive, objective reviews.   Other online mattress reviews can be biased by payments from mattress manufacturers.  Beginning in 2006 online mattress companies have been taking over the mattress industry with high quality, value-priced mattresses that can meet nearly everyone’s needs.  The hard part is choosing the best mattress for our own bedroom.  

The Black Friday sales this year brought the already great prices on many of these mattresses even lower.  I decided that now was the time buy.  You have probably heard of many of the highly rated brands such as Tuft & Needle, Casper, Tempurpedic, and Purple.  The luxury brand Duxiania makes wonderful, well-designed beds, but at $5000-15,000 they are well out of my price range.   A few months ago my daughter needed a new mattress for her apartment at college.  I wanted a comfortable mattress for her, but cost was also an important factor.  The Zinus Green Tea Memory Foam Pressure Relief Mattress was available on Amazon.com and was available for Prime shipping.  She found it to be “comfy” and her roommate (her sister) needed a mattress, to replace her lumpy, second hand mattress so I bought the same mattress for her.  Not to be left out, my third daughter got the same mattress.  

A few days ago our new Zinus Pressure Relief Memory Foam Cloud Mattress arrived at our front door.  Today we opened it up.  This is my first “bed-in-a-box” and I found that the process could not have been easier.  

The interior flap of the box cheerfully greeted me with, “Hello, wonder has arrived.”  Opening the box revealed the mattress wrapped in clear plastic and an envelope with instructions that describe the process of unpacking the mattress.  Less than 5 minutes later the mattress was unfolded and expanding on my Zinus SmartBase Platform Bed Frame.  The mattress was already taking shape 60 seconds later.  The cover is made of attractive, soft quilting and quality edge piping.  It already seemed like this was $300 well spent for this queen sized mattress.   

It can take a bed-in-a-box 4 – 6 hours to expand to 90% of its full size and then another 4 – 6 hours to expand to its full size.  We left the mattress to do its thing for the afternoon.  Then we made the bed.  It is always a good idea to use a mattress protector to keep dust from accumulating in the quilted cover of your new mattress.  We are using the SafeRest Premium Hypoallergenic Waterproof Mattress Protector.  

Then it was time to take the mattress for a spin.  The mattress is “plush” and soft.  It cradles pressure points when lying on my side and is supportive when lying on my back.  Both of us tend to have back pain and we prefer to sleep on a bed that is in that Goldilocks zone of neither too hard nor too soft.  The old wisdom that having an extra firm mattress if you have a back pain is simply false.  The best mattress for people with back trouble is one that is supportive and yields to the body’s contours.  This mattress does that very well.  Movement on one side is stabilized when one person rolls over the other side does not feel vibration.  

Even though Consumer Reports does not rate Zinus beds, my verdict on the Zinus Pressure Relief Memory Foam Cloud Mattress is positive.  Not only is it better than the Spring Air Mattress it is replacing, but it is simply an excellent bed.  It is too early to tell how durable this mattress will be.  

I will be recommending this bed to my patients who want a comfortable, inexpensive replacement to their old bed.  If you want a comfortable mattress at a great price, I suggest that you consider Zinus.