What’s Really the Best Sleep Position? A Scientific Breakdown

Sleep Positions

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In this article, I hope to give you a unique perspective on which sleep position is truly optimal for the human body.

After having spent hundreds of hours pouring over hard-to-find books and research papers and having spent years trying out a variety of sleep positions myself, I’ve come to the conclusion that the best sleep position is the neutral body posture, better known as the zero-gravity position.

Let’s go over just why that is!

Advantages and Disadvantages of Typical Sleep Positions

First, let’s lay some groundwork on each of the main sleep positions and what I believe their pros and cons to be.

While there are many variants of each of these positions, the base position itself remains mostly the same.

The Lateral or Fetal Position

The vast majority of humans prefer to assume this position during sleep due to its intrinsic comfort.

Pros:

  • Fully relaxed: It’s likely this position is preferred by many due to the possibility of bending the hips and knees, allowing for full relaxation of the sacroiliac muscles as well as the lumbar spine.
  • Neutral spine: It’s possible to assume a neutral spine in some lateral positions.

Cons:

  • Facial deformation and aging: It’s very likely that facial compression leads to the advanced formation of wrinkles and general deformation of the face over long periods of time. [R] [R] [R]
  • Tossing and turning: Side sleepers will toss and turn throughout the night as the body attempts to compensate for excessive compression of tissues. This of course interrupts sleep processes that can only occur when the motor functions of the body have been shut down, such as REM.
  • Appendage numbness and circulation: Loss of circulation and numbness in the extremities is common in this position, limiting blood flow and the excretion of metabolic waste.
  • Head congestion: Assuming you’re sleeping on a flat surface, whatever side you choose to sleep on will get congested overnight. Many people with sinus issues and allergies will know this, as they will wake up with one side of the body effected more than the other. [R] [R] [R]
  • Non-neutral spine curvature: The fetal position can cause the spine to be curved into a non-neutral position, possibly reducing the effective rehydration of intervertebral areas as well as contributing to back pain.
  • Abdominal compression: Trunk flexion can increase intra-abdominal pressure, which can limit diaphragm expansion and negatively impact breathing fullness.
  • Odd spinal rotations: Some positions can cause odd lumbar and sacral rotations due to the unsupported top leg. This can be alleviated with a pillow between the knees.
  • Breast compression: If your breasts are large enough, the breast closest to the bed will be compressed during side sleeping, limiting blood flow and metabolic waste removal.
  • Trigeminal nerve compression: Side sleeping compresses the jaw, temple, and forehead. You may even notice that you can hear your heartbeat while lying on your side, this is because of the compression of the arteries near the ear. This area is also where the trigeminal nerve exits the skull to supply the facial region with nerve endings. It’s possible that compression of this area could result in pain or discomfort in the face as found in trigeminal neuralgia.

The (Horizontal) Supine Position

The supine sleep position is the second most common sleep position and is far more common in asian countries than in western countries. This could be due to a difference in the lumbar curvature in these respective populations. [R]

Pros:

  • Less movement disruption: Movement, and thus sleep interruption, is lowest in this position due to more weight being distributed across a larger surface area.
  • Minimal organ compression and impingement: Back sleeping keeps organs from pressing upon one another and keeps the heavy back off of the organs, unlike stomach sleeping.
  • Neutral spine: Baring a terrible mattress system, the supine position is the easiest with which to maintain a neutral spine.

Cons:

  • Breathing difficulties: Breathing difficulties are most common in this position due to gravity ultimately narrowing the esophagus at night.
  • Lumbar discomfort: Depending on your ethnicity (asians seem to have less lumbar curvature) laying flat on your back can cause a pressure spike in the lumbar area.
  • Iliopsoas discomfort: Again, a curved lumbar area means your Iliopsoas muscles won’t feel fully relaxed unless your hips and knees can be bent, hence the preference for lateral positioning.
  • Ulnar nerve impingement: By laying on your back and placing your hands and arms across your abdomen, you run the risk of compressing the ulnar nerve. This can be mitigated by inclining the torso (less pressure), keeping your arms at your sides, and/or by placing pillows at your sides to distribute pressure more evenly across the elbow area.

The Prone Position

The prone position is the least common of all assumed sleep positions. Which is no surprise really.

Pros:

  • Uhhhhhh: I’ll be honest, I can’t think of any. I suppose some people find it comfortable, so we can count that.

Cons:

  • Facial deformation and aging: It’s very likely that facial compression leads to the advanced formation of wrinkles and general skin deformation. [R] [R] [R]
  • Breast compression: This will be an even bigger issue than in the lateral position. Compression of the breast tissue will limit blood flow and metabolic waste removal.
  • Male sex organ compression: Again, we risk excessive compression of soft tissues in the prone position.
  • Shallow breathing: The rib cage is meant to expand outwards as we breathe, stomach sleepers will have trouble breathing fully or deeply throughout the night.
  • Internal organ compression: Stomach sleeping means that the internal organs must bear the weight of the back, which is composed of mostly bone and muscle, meaning it’s quite heavy. This could result in reduced blood flow throughout the abdominal cavity.
  • Nostril compression: This position can result in partial compression of the nostrils, again producing shallow breathing.
  • Neck rotation issues: Stomach sleeping requires the neck to be turned 90 degrees from baseline, this can cause strain in the cervical spine and pain upon waking.
  • Facial compression: Facial compression will be greater for stomach sleepers than side sleepers. Side effects of this may be a bent nose, puffy eyes, wrinkles, and sinus congestion.
  • More frequent urination: Since the bladder is located near the front of the abdomen and stomach sleeping puts more pressure on the bladder, it will feel fuller, sooner, resulting in more frequent bathroom trips and interrupted sleep.

A Case for the Neutral Body Posture Sleep Position

It’s interesting that the qualities that make the lateral position so attractive and comfortable can be seen in astronauts in microgravity. The neutral body posture (NBP) is the posture the human body tends to naturally assume in microgravity, meaning any deviation from this position requires muscular effort. [R] [R]

3d representation of STS 57 crew member neutral body postures in microgravity
Neutral body postures for six crew members from Space Shuttle mission STS-57. (Source)

The NBP is also used in car seat design, hospitals (semi-fowlers position), and bedding as the “zero gravity position”.

2d representation of fowlers sleep position
Semi-Fowlers Position

So why is this position such a great position to sleep in?

Like the supine position, it’s optimal from a spine and pressure standpoint; and because the upper body is slightly elevated, it prevents brain congestion and breathing difficulties. The knees and legs are also angled (and elevated) to alleviate pressure from the lumbar spine and improve circulation in the legs.

Migraines, Strokes, Glucose and Pressure

The cause of migraines is said to be unknown, but let’s go over some interesting facts that invite a theory for causality.

  1. Low blood sugar (hypoglycemia) is strongly correlated with migraines and headache prevalence. [R] [R] [R]
  2. Headaches and migraines occur most often in the early morning hours. [R]
  3. Women get far more migraines and headaches than men, especially around their menstrual cycle. High estrogen and low progesterone can lead to fluid retention and bloating, likely leading to the higher incidence of female related migraines and headaches. [R]
  4. Both men and women have fewer migraines as they age, possibly due to a decline in Cerebrovasodilator capacitance, with women having the majority of migraines and headaches. [R] [R] [R] [R]
  5. Women who used birth control for >3 years were roughly 2x more likely to self-report with glaucoma and ocular hypertension. Women are also at a 2-3x higher risk for glaucoma than men. [R] [R]
  6. Migraines may be a protective mechanism triggered by the brain. [R] [R]
  7. Migraines frequently cease after vomiting, which severely increases blood pressure to the head, likely producing a huge flushing of extracellular fluid. [R]
  8. Longer sleep durations are associated with an increased risk of stroke. [R] [R]
  9. Strokes tend to occur in the first half of the day and early morning, with most occurring in a two-hour window following waking. [R] [R] [R]

I think it can be postulated that migraines and headaches likely have something to do with intracranial pressure, hypertension, sleep, and blood sugar levels in the brain.

When sleeping horizontally, your body must lower its heart rate and blood pressure as the pressure in the brain increases.

This leads to fluid retention and swelling in the brain over the course of the 8 hours that the brain and heart are at the same level.

Ask yourself, do you ever wake up with puffy eyes, congested sinuses, eye gunk, general grogginess, or maybe even a headache?

These are all signs of excess fluid pressure buildup in your cranium. If you experience any of these things, simply sleep elevated for a couple of days and watch them disappear!

It seems that given all the interesting facts above, for some – especially women – the increase in cranial pressure during the night decreases blood circulation, starving the brain of optimal glucose levels for hours. In the morning, once normal pressure is attained, the brain seizes this opportunity by opening the neck arteries wide, allowing fresh blood, oxygen, and glucose to replenish the brain. This results in an episode of extreme pain as the expanding blood vessels and arteries push up against nerve tissue.

If you’d like to learn more about this, I highly recommend checking out “Get It Up”. While the title is a turn-off for most, it’s a treasure trove of information, and it’s the only book I’ve found that truly explores the pros and cons of certain sleeping positions.

Sleep Apnea and Sleep Position

Many of us are deterred away from back sleeping due to sleep apnea being positively associated with this position, luckily elevating the torso slightly can severely diminish this issue. [R] [R] [R] [R]

It’s interesting to note that sleep position doesn’t seem to affect sleep apnea prevalence in young children, as it does for older children and adults. [R] [R] [R]

My guess is that sleep apnea prevalence begins to appear as bad lifestyle choices begin to take hold and things like insulin resistance, inflammation, and weight gain start to affect breathing patterns.

It’s also well known that mouth breathing is associated with Obstructive Sleep Apnea (OSAS) . [R] [R] [R] [R] [R]

If you’ve been diagnosed with OSAS and want to try elevated sleeping, just make sure to keep track of your symptoms. You may want to consider mouth tape, nasal dilators, and maybe even a pulse oximeter.

You can read through my guide on nasal breathing for more information on how to get a handle on that.

Bed/Seat Design and Pressure

Again, it’s interesting that we see the neutral body posture continue to show up in a variety of different ways.

  • Fifteen patients were selected by a hospital to find the optimal bedding position for contact pressure distribution. It was found that head and foot at 30° was best. [R]
  • In this study, which assessed which reclined position would best distribute weight in an autonomous car, it was found that a position very similar to the neutral body posture was optimal. However, it’s worth noting the subjects did prefer the more relaxed position (in black). [R]
human outlines of seat pan positions from study
Longitudinal space requirement of the biomechanically preferred position (grey, 40°–155°), as compared to the subjectively preferred configuration (black, 20°–165°) (Source)

How to Sleep on a Zero Gravity Bed

So if you’re ready to begin, let’s talk about how this works!

First, if you’re already a back sleeper, you’re obviously in luck, this will be a lot easier for you.

If you don’t currently sleep on your back, imma be upfront with you, it probably won’t be easy for you to change that. It’s going to take time, and no small amount of frustration…but you got this!

Luckily, there are ways to make the transition easier which we will now discuss.

Learning How to Sleep on Your Back

For the veteran back sleepers out there, start out slow by adding a slight incline. A sudden dramatic shift in the incline might cause you problems, so we definitely want to make the adjustments gradually.

For you side sleepers, and those weird stomach sleepers (you know who you are), you’ll want to take things even slower and implement some strategies to make this transition a bit more comfortable.

  • Give it a few weeks or months: If you’ve built up the habit of sleeping one way for your entire life, don’t expect to be able to change it at the drop of a hat. It’s going to take some time, and you should be mentally prepared for that.
  • Fall asleep on your side: Expecting to easily be able to fall asleep on your back is a mistake bound to leave you laying in frustration for hours. Try this instead: Fall asleep in your preferred position initially and when you wake up in the middle of the night, try to fall back asleep on your back instead.
  • Make sure you’re tired: Adjusting to a new sleep position will be a lot harder if you’re going straight from work to bed. See my guide on relaxing before bed for instructions and ideas on how to help your body grow tired naturally.
  • Place pillows by your sides: It can be useful to simulate side sleeping by placing pillows at your sides, this can help make the position change feel less alien.
  • Use an adjustable pillow: A pillow that you can adjust so that it can be pressed around the cranium will work similarly to the side pillows, emulating the feel and familiar comfort of side sleeping.
  • Use a gravity blanket: Gravity blankets can help to quell that restless feeling you might get when sleeping in an unfamiliar position by adding a comforting weight across your body.

Best Adjustable Pillow

  • Shredded Talalay Latex Pillow: This adjustable pillow filled with 100% natural shredded talalay latex will allow you to find the perfect fill for you. The fact that it’s talalay latex will also ensure that it remains a stable breathable temperature all night long.

Best Gravity Blanket

  • Bearaby Tencel Weighted Blanket: While not the cheapest, these are the best weighted blanket options on the market due to their breathable weave. The Tree Napper made of lyocell fabric would be the best from a thermal perspective. Alternatively, the cotton and Nappling blankets are a good budget option that will still breathe infinitely better than beaded weighted blankets.

What Angles are Ideal?

Let’s go over what angles you might find personally beneficial. These are just guidelines to follow, you’ll need to find your own sweet spot.

  1. In general, a minimum of 5° torso elevation is ideal – all we are looking for is the head to be above the heart.
  2. Set a maximum torso elevation of 30° – higher than this may impair your ability to relax properly. Those with pressure related health symptoms may benefit from getting closer to 30°.
  3. Elevate the legs with a slight bend in the knees to a mild level- usually around heart level. But ultimately, the level that you find most comfortable is ideal.

Buying a Zero Gravity Bed Base

When considering a zero-gravity bed base, here are some things to keep in mind:

  • Memory functions: You may wish to make the bed flat sometimes for non-sleep related activities, and it can be a pain to manually put everything back to that perfect spot you spent weeks finding. Pricier bed bases can include a memory function, which might be worth paying for. Alternatively, you can simply measure from the floor to the mattress and write it down. This way, you can always find your way back to that perfect spot.
  • Airflow design: Getting an adjustable base with an open grid structure will help with airflow through your mattress, thus promoting thermoregulation through the night.
  • Split-king setup: While it will cost more up front for two separate bases, this will allow both you and your partner to find your own sweet spot. This will also limit motion transfer disturbances, which is a nice bonus.
  • Slanted leg section: Some bed bases have slanted leg sections and some have flat ones. I’d recommend the ones with slants, as these tend to be a bit more comfortable since they achieve a more neutral position.
  • Mattress selection matters: Depending on your current mattress, you may need a new one. Some just don’t work very well on adjustable frames, as they’re too light or too rigid. Latex generally works the best, while foam and spring mattresses can work, certain kinds just aren’t as friendly. Something to keep in mind.
  • Alternatives to a bed base: If you’d like to try out sleeping in the neutral body posture but don’t have the cash to throw down on a bed base, you can try just using foam wedges with or without bed risers. I’ve included examples of these below. The disadvantage of this option is that is takes up space on your bed and isn’t as customizable like a bed base.

Best Adjustable Bed Bases

  • Lucid Adjustable Bed Base: This is the most affordable bed base I’ve found with a memory function.
  • Open Grid Adjustable Bed Base: This is the best adjustable base I could find with an open structure design. Unfortunately, I have yet to find one with a memory function, so you’ll have to make the call!

Best Alternatives to Bed Bases

  • Brentwood Home Cushions: These look like some of the best foam cushions around, if you’d like an alternative to a bed base.

  • Bed Risers: You can pair bed risers with a leg cushion to simulate the zero gravity sleep posture on the cheap.

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