A Degree of Relaxation That Defies Dignity

If you’ve ever walked onto my property unannounced, there’s a decent chance you’ve been greeted by a 35-plus kilo dog lying completely spread-eagle on the grass.
Legs in the air. Belly exposed. Zero shame.

Affectionately, he’s known as Sammy Sunshine, because he’s always smiling. But his private nickname is Moses - because when we walk down the street, people tend to part the footpath as if he’s leading an exodus. Which is ironic, really, because beneath his size and presence he’s one of the gentlest dogs you could ever meet.

Sammy is a rescue dog. A big, mixed-breed softy who gets along with everyone, feels comfortable everywhere, and sleeps like he’s auditioning for a yoga lifestyle shoot. On his back. Always. Completely relaxed. Often in places that make visitors stop mid-sentence and laugh.

At first, I just thought it was funny. My mother once told me that as a baby, I had a habit of sleeping with one leg straight up in the air, so maybe there’s a family precedent for bizarre but apparently comfortable sleep positions.

Interestingly, babies often end up in some very creative sleeping positions, including the classic one-leg-in-the-air pose. It’s thought to be a natural way to get comfortable, settle the body, and even relieve digestive discomfort, while also supporting early muscle use, coordination, and temperature regulation as their nervous systems develop.

Anyway, back to the dogs… When I looked more closely at how Diesel - and every dog I’d lived with before him actually slept, I started to form a theory. You see, Sammy is the first of my dogs to sleep this way.

Diesel, for example, is friendly, affectionate, and gentle - but he’s also alert. He’s aware of his surroundings. He chooses spots in the house where he can see doorways, hear movement, and respond quickly if needed. Even when he’s relaxed, there’s a sense that he’s “on duty.” Diesel only shows his belly for rubs.

Two very different dogs. Two very different sleeping preferences.

And then there were Augustine and Faith.

Both beautiful dogs. Both deeply bonded. Both loving. Augustine was generally very trusting of people, but could be reactive around dogs she didn’t know.

Faith came to me at 11 months of age from an abusive environment, where she had been physically hurt. That early trauma shaped her lifelong sensitivity to change and unfamiliar situations. Both dogs were aware, sensitive, and watchful - and neither of them ever really embraced the upside-down, legs-in-the-air lifestyle, except during again, for belly rubs. That difference got me thinking.

Is this really about comfort… or is it about something deeper?

The “Belly-Up” Position Is Vulnerable on Purpose

Sleeping on the back is one of the more vulnerable positions a dog can choose. The abdomen and chest are exposed. Getting upright takes a fraction longer. If you picture survival instincts, it’s not exactly a tactical posture.

Which is why it’s commonly interpreted as showing a dog feels safe and relaxed in its environment. Behaviour explainers that break down dog sleeping positions often describe belly-up (and other exposed-belly positions) as linked with comfort and security.

And when you put that next to my two dogs, it makes sense.

Sammy feels safe everywhere. New people. New environments. New noises. He doesn’t feel the need to monitor or control space. His body language - including how he sleeps - reflects that.

Diesel, Augustine, and Faith weren’t unhappy dogs. They were just more tuned in. More watchful. More likely to keep one ear open, even when they were resting.

This isn’t a personality contest. It’s simply different nervous systems doing what they’re wired to do.

Why Every Dog Experiences the World Differently

Dogs don’t all experience the world in the same way, even when they’re living in the same home. Behaviourists often describe dogs as having different default behavioural strategies - shaped by genetics, early life experiences, and individual temperament.

Some dogs naturally lean toward a more protective or monitoring role, staying aware of their surroundings and maintaining a degree of distance, even when relaxed. Others are more social, tactile, and affiliative, seeking closeness, physical contact, and connection as their baseline state. These tendencies can quietly influence everything from how affectionate a dog is, to where they choose to rest, to how deeply they are able to switch off.

In that context, behaviours like sleep position aren’t random - they’re often a reflection of how a dog’s nervous system is wired to relate to safety, connection, and the world around them.

It's a Cooling Strategy

There’s a physical side to it too.

That belly-up posture can help with thermoregulation. Exposing the underside of the body increases surface area and can help a warm dog cool down, which is one reason many dogs choose a sprawled, open posture in warmer conditions.

From a physiological perspective, this makes sense. Areas such as the abdomen, inner thighs, and chest have less fur and greater blood flow, allowing excess body heat to dissipate more efficiently when exposed to cooler air or surfaces. By opening up these regions, the body can release heat more effectively than it can when curled up or lying on its side.

But here’s the interesting part: plenty of dogs get warm. Not all of them flip upside down. So yes, comfort matters but feeling safe enough to be that exposed matters more to them.

The Cortisol Connection

This is the part I wanted to approach carefully, because it’s very easy to make a leap that sounds convincing but isn’t actually supported by evidence.

Cortisol is a normal and essential hormone produced by the adrenal glands as part of the hypothalamic–pituitary–adrenal (HPA) axis. It plays a role in how a dog responds to challenges, mobilises energy, and maintains normal daily rhythms. We also know that stressful situations can increase cortisol in dogs, and that chronic, ongoing stress can place strain on this regulatory system over time.

Conditions such as Addison’s disease and Cushing’s disease are not diagnosed based on behaviour or cortisol levels alone, but are typically confirmed through veterinary blood testing, often using specific adrenal function tests (such as ACTH stimulation or suppression tests) to assess how the adrenal glands are responding.

So does sleeping on the back reduce cortisol?

I can’t say that - and it’s important to be clear about that. There’s no evidence to suggest that sleep position itself is a proven cortisol-lowering intervention, and it would be misleading to claim that dogs who sleep belly-up have a lower risk of adrenal disease simply because of how they rest.

What is reasonable to say is something slightly different - and, in my view, far more useful.

If a dog is calm enough to consistently sleep in a posture that exposes their most vulnerable areas, that dog is likely spending more time in a low-threat, relaxed state within their environment. In general terms, animals that spend less time in a chronic vigilance or stress state are less likely to be living with sustained stress physiology. Chronic stress is the pattern most commonly associated with cumulative strain on regulatory systems, including the HPA axis that governs cortisol production.

So the “cortisol connection” isn’t that back sleeping fixes the adrenals.

It’s this: belly-up sleeping can be a behavioural clue that a dog feels safe, settled, and downregulated, and that kind of baseline calm is generally compatible with healthy stress regulation.

There are always exceptions. Some dogs roll onto their backs because it feels good on their spine, and some dogs can be confident and relaxed without ever choosing that posture at all.

But as a broad behavioural signal, it’s still a meaningful one.

A Quick Note on Adrenal Problems

When people talk about “adrenal issues,” they often mean a wide range of things.

True adrenal diseases, such as Addison’s disease (hypoadrenocorticism) or Cushing’s disease (hyperadrenocorticism), have specific causes and diagnostic pathways. Addison’s, for example, is most commonly the result of immune-mediated destruction of the adrenal cortex, often arising without a clear or controllable trigger.

So while reducing stress and supporting a calm, secure lifestyle is absolutely beneficial for overall wellbeing, it wouldn’t be accurate to suggest that a dog’s sleeping position predicts or prevents these endocrine conditions.

Why Sammy goes full spread-eagle

Sammy doesn’t just sleep on his back. He commits to it.

Legs wide. Belly up. Head twisted sideways. Sometimes blocking hallways. Sometimes directly in front of guests. Always completely unbothered.

And honestly, it’s hilarious. He looks ridiculous. He knows it. And he doesn’t care.

That ease is what made me curious enough to look deeper. Because when you compare him to Diesel - who is equally loving, but far more monitoring the room - you start to appreciate how much a dog’s default nervous system style shapes everything, right down to how they rest.

Should You Worry If Your Dog Doesn’t Sleep This Way?

No.

Some dogs are observers. Some dogs are guardians. Some dogs just prefer other positions. Side sleeping, curled sleeping, belly-down sleeping - none of that automatically means stress or a problem.

But if your dog does sleep belly-up regularly, it’s usually a lovely sign that, at least in that moment, they feel safe enough to fully let go.

And if your dog never does? It doesn’t mean you’re doing anything wrong. It may just mean you’ve got a Diesel, not a Sammy.

Final thought

Watching Sammy sleep upside down all over the house didn’t just give me endless photo opportunities. It reminded me that behaviour is often the clearest window into how a dog truly feels.