Eight Sleep Mars+ Smart Mattress Review

In 2014, the bed-in-a-box concept began to pick up speed, and this is when Eight Sleep was founded. They saw the innovation involved with allowing consumers the ability to shop for their mattress without the pressures of the retail experience. They didn’t stop their with their cutting-edge approach, however. Eight Sleep has gone a long way in helping people understand their sleep to the point of using technology to reveal important information to achieve the best sleep possible.

I recently received the Mars+ mattress. This is the most luxurious model of the three offered by Eight Sleep, and it has a lot to offer people who carry a lot of weight and/or sleep hot. This product is a total of 11 inches thick, and I was especially impressed with the material you’ll find in the first layer as it takes a unique approach in balancing contour and bounce. If you suffer with pressure points and have mobility issues, you’ll definitely want to keep reading.

Buying online is very convenient, but you have to take your time. After all, there are many options, and you want to ensure you’re investing in the one that’ll prove to be the best fit for you. The great news is that I’ve done all the hard work for you. I’ve performed various tests and looked at the Mars+ mattress both inside and out. Keep reading our complete Mars+ mattress review to get a better idea of how it could work out for you.

The Good

  • Included AI-Powered Sleep Coach allows you to track biological data that can help you sleep better
  • Keeps motion transfer low
  • Sleeps cool
  • Great combination of bounce and contour in layer one
  • Materials are Certi-Pur US certified
  • 100-night sleep trial
  • Thin cover helps you engage with foam layers
  • Innersprings offer good edge support
  • Medium-soft firmness accommodating for most shoppers

The Bad

  • Expensive
  • No firmness options

Our Score

For every product I hand test, I take a moment to provide a rating so you can take a quick look at what to expect. In the case of the Mars+ mattress, here’s the breakdown:

  • Comfort
    • 9.0
  • Pain Relief
    • 9.0
  • Edge Support
    • 9.0
  • Durability
    • 8.5
  • Offgassing
    • 9.0
  • Back Sleeping
    • 9.0
  • Side Sleeping
    • 9.5
  • Stomach Sleeping
    • 8.0
  • Warranty and Support
    • 8.5
  • Value
    • 9.0

What It’s Made Of

Before we get too in-depth into how this product feels, let’s take a look at what’s inside. This gives you a better idea of how it works to keep you sleeping soundly. The Mars+ is a hybrid mattress, and this means it uses a combination of different material types to come up with a combined unit that offers superiority in things like support, contour, and overall comfort. Let’s look at the breakdown of the 11 inches of the Mars+ mattress.

The Comfort Zone

There are four total layers, and the first two comprise the comfort zone. It starts off with two inches of Reactive Foam. This is a unique concept as it was designed by Eight to hug like foam but react like latex. Traditional memory foam was notorious for excessive sinkage, but this unique feel addresses that problem without cutting back on the contouring ability.

Layer two is composed of another two inches of Comfort Transition Foam. It works as a buffer between the comfort and support zones and relieves pressure in the hips and back.

The Support Zone

Beneath the transition foam is a four inch layer of sleeved coils. Innerspring units are well known to provide great support, but they can be too bouncy. I like that the coils in the Mars+ are individually-wrapped. This allows you to move around with minimal disruption to your sleep partner. They also offer:

  • Cloud-like bounce
  • Excellence in air flow
  • Polyfoam cover to help mattress sleep cool

At the bottom of the Mars+ mattress lies a final layer of high density support foam. By incorporating high density, Eight Sleep works to ensure good durability.

The Cover

I found the cover to be very comfortable, and it’s composed 100 percent of polyester. It’s very thin, and I think this works well, especially for people who don’t weigh a whole lot. This is because it allows you to engage well with the comfort layers. When you lie down, it does cause a little bit of bunching on the layers. However, it’s pretty easy to straighten them out by running your hand over them.

A Look at the AI-Powered Sleep Coach

Most of us are aware that you need around eight hours of sleep. We also generally understand the importance of sleeping cool. However, how do we know for sure our sleep temperature, time spent sleeping, and other intricate information so critical to restful sleep?

Eight Sleep provides their AI-Powered Sleep Coach with the purchase of any of their three mattresses. Using a cover discreetly armed with sensors in the chest area, it monitors and records heart rate, respiratory rate, bed temperature, and room temperature. Using this information, it can determine:

  • When you fall asleep
  • When you wake up and how long you lie in bed before getting up
  • Tosses and turns

Every morning, your app that connects with the hubspot that plugs into the cover tells you how well you slept. It recognizes patterns and potential problem areas to help you make the most out of every hour spent in bed. It can also connect with smart devices like Alexa, making it among the most innovative sleep products I’ve tried out.

Hands-On Mars+ Mattress Review

Using the online business model in the quest for your next mattress, you eliminate a lot of stress from the experience. Not only do you avoid driving from one retailer to the next, but you also get to avoid being hustled by fast-talking sales people.

The only hangup is that you don’t get the chance to lie down and feel the mattress before you buy. That’s where we step in. I have had the chance to take a close look at this product, and I’m here to provide you with a non-biased review to help you make an informed decision. So, let’s break down the Mars+ mattress to see what you can expect. Some of the components we’ll examine include:

  •        Firmness
  •        Comfort
  •        Pain Relief & Support
  •        Heat Retention (how cool the mattress remains)
  •        Off Gassing (the odor the mattress emits)
  •        Intimacy


The Mars+ mattress is advertised as a medium-firm product. I found this to be pretty accurate. On a scale of 1-10 with one being very soft and 10 being very firm, I’d rate it at around a 4.8. For the most part, this mattress should be accommodating for the majority of customers. However, due to its slightly plusher firmness, it should appeal particularly to:

  • Sleepers with a BMI of 19-23
  • People who sleep on their sides
  • Those who appreciate a slightly firmer sleep surface


I found the Reactive Foam to be a very interesting material that executed its goal very well. A material combination you see often is memory foam and latex. However, one obviously must be placed above the other, allowing its properties precedence. In the creation of a material that mimics the qualities of both, the Mars+ mattress offers a unique feel that does an excellent job at providing that latex bounce while still offering contouring comfort.

I also appreciate the combination of the transition foam with the coils. This is where the cloud-like comfort comes from. If you like to feel like you’re floating on your sleep surface, this is what it feels like.

Pain Relief and Support

The Mars+ does an excellent job at pain relief, and this is primarily credited to the Comfort Transition Foam found in layer two. It’s designed to provide relief in common pressure point areas like the hips and shoulders. I think Eight did a good job in placing this layer right above the coils to act as a buffer. This smooth transition allows for excellent support without compromising on effective pain relieving properties.

Heat Retention

Your body temperature has to drop before you enter REM sleep. It’s during this state when your body is able to fully recover from the stressors of the day. Eight makes it easy to achieve. Using the AI-Powered Sleep Coach, you can see what percentage of your total sleeping time was spent in REM sleep. The mattress does a great job at cool sleeping, and I think this is primarily due to the naturally-breathing coil unit.


Ahh, the new mattress smell. For some people, it’s no bother. However, others can’t stand it. If you’re in the latter group, you’ll be happy to know that offgassing for the Mars+ mattress doesn’t take very long. It only took about a day and a half for my mattress to air out after I got it out of the box.

If offgassing really bothers you, I’d suggest letting yours air out for a day before you sleep on it. I wouldn’t put on sheets or your AI-Powered Sleep Coach until it’s had some time to air as this slows the process of the release of volatile organic compounds. You should also open the mattress as soon as possible after receiving it to avoid a longer offgassing period.


Mattresses containing spring units are typically pretty good at facilitating intimacy. The sleeved coils along with the reactive foam in layer one work well together to help you engage in easy movement on the mattress surface. You don’t feel like you’re sinking in or having to exert unnecessary energy due to excessive hug.

Sleeping Position Ratings

Of all the possible weird sleep positions you can find yourself in, stomach, back, and side are the most common. You may have a favorite or find that you switch around through the night. Whatever the case may be, it’s important to understand how these positions will work with your sleep surface before you buy.

Let’s take a moment to talk about how the Mars+ mattress accommodates these three primary sleep positions:

  • Side
    • For side sleepers, a medium to soft mattress is your best bet. Since this mattress is a medium-soft, it makes for an ideal firmness to facilitate this sleep position.
      • Side Sleeping Score: 9.5 / 10
  • Back
  • Stomach
    • Stomach sleeping is best facilitated by a medium to firm mattress. Since this mattress is so close to medium, I think it can work well for stomach sleepers. However, if you carry a lot of weight, you may want to look for something more on the firm end of the spectrum.
      • Stomach Sleeping Score: 8.0 / 10

Bed Frame Compatibility

Eight recommends using the Mars+ mattress with a breathable slatted base or box spring. Just make sure your slatted base doesn’t have any gaps more than three inches. Solid foundations like the floor or wood don’t allow for proper breathability. It also makes your mattress more susceptible to the development of mold.

If you want to play it safe, you can always go with a base designed specifically for use with Eight products. Their Simple Foundation only takes minutes to put together and runs $275.

Warranty, Guarantee and Trial Period

  •        Warranty: 10 years
  •        Guarantee: Full money back guarantee for any manufacturing-related issues
  •        Trial Period: 100 nights


Of the three mattresses manufactured by Eight Sleep, the Mars+ is their most luxurious. I think you’ll enjoy the degree of engagement you’ll experience with the thin cover, and I like that it’s medium-soft firmness is well-suited for all three sleeping positions. It can also be a great option for sleep partners with its low motion transfer. Best of all, the included AI-Powered Sleep Coach can help you understand your own sleep patterns better than ever to get the best sleep possible.

Is the Mars+ Mattress Right for You?

So, is the Mars+ mattress right for your needs? Let’s recap the main points to help you decide. Do you:

  • Have a sleep partner?
  • Suffer with painful pressure points?
  • Like the feeling of memory foam but don’t want to feel like you can’t move?
  • Enjoy great edge support?
  • Want to learn more about your sleep patterns?
  • Sleep hot?

If you answered yes to any of these questions, the Mars+ mattress is definitely worth consideration.

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