A dog resting
on September 17, 2026

Dog Panting at Night: Causes & When to Worry (UK Guide)

A dog panting at night is usually just regulating their temperature or working off some leftover excitement — but in a calm, resting dog, especially an older one, it isn't always nothing. There's a specific, named condition behind a lot of unexplained night panting in senior dogs that most owners have never heard of. This guide covers the harmless causes, the medical ones worth ruling out, the real reason so many older dogs get restless specifically after dark, and when it's time to see a vet.

Written by Jamie Sinclair, who writes about canine health, nutrition, and everyday care for Doggy Dailies — focused on translating veterinary research and real ingredient science into practical, honest guidance UK dog owners can use.

A dog resting

Table of Contents

Normal, Harmless Causes

  • Heat — a warm bedroom, thick bedding, or poor airflow can trap heat around a sleeping dog, and panting is how dogs regulate temperature since they don't sweat the way we do
  • Leftover excitement or stimulation close to bedtime — a late walk, play, or an exciting event in the evening
  • Anxiety or stress — thunderstorms, fireworks, a change in routine, or being away from familiar people can all trigger panting as a stress response
  • A medication side effect — some common medications list panting as a known effect

A dog who pants briefly after settling down, then relaxes into normal sleep, is very likely dealing with one of these. The pattern that's genuinely worth paying attention to is different, and it's covered next.

Sundowning: The Named Condition Most Owners Have Never Heard Of

This is the piece most generic panting articles skip entirely, and it specifically explains a pattern a lot of senior-dog owners notice without knowing what it's called: restlessness, pacing, and panting that reliably starts in the evening or after dark. It's called sundowning, and it's part of canine cognitive dysfunction syndrome (CCDS) — the canine equivalent of dementia. Sundowning specifically disrupts a dog's sleep-wake cycle, making the evening and night hours the time when confusion, restlessness, and anxiety-driven behaviours like panting are most likely to show up, even though the same dog might seem largely normal during the day.

Vets use a memorable framework — DISHAA — to describe the range of cognitive dysfunction signs: Disorientation, changes in Interaction with people or other pets, Sleep-cycle changes, House soiling, changes in Activity, and increased Anxiety. Night panting tied to sundowning usually comes alongside at least one or two of these — pacing, seeming lost in familiar rooms, or a dog who now sleeps through the day and is awake and unsettled at night.

This isn't a rare, edge-case condition — cognitive dysfunction becomes common with age. A peer-reviewed cross-sectional study of 325 geriatric dogs (aged nine and over), published in the Journal of Small Animal Practice, found signs of cognitive impairment in 22.5% of them — roughly one in four to five — based on structured interviews with owners. Prevalence and severity increased significantly as the dogs got older, and the same study found females and neutered dogs were significantly more affected than males and entire dogs. Given how common it is, unexplained night panting and restlessness in an older dog is genuinely worth raising with your vet as a possible early sign, rather than assuming it's "just getting old" with nothing to be done. Management options exist — from environmental changes to specific medications your vet may discuss — and starting them earlier tends to help more than waiting.

Other Medical Causes Worth Ruling Out

  • Cushing's disease — a hormonal condition, more common in older dogs, causing excess cortisol; along with panting, watch for increased thirst, increased appetite, and hair loss
  • Heart disease — conditions like mitral valve disease can cause laboured or heavy breathing that's often worse lying down and worse at night, sometimes alongside a cough
  • Respiratory disease — anything from a collapsing trachea to airway inflammation can compromise normal breathing; blue, purple or grey gums or tongue alongside panting is a genuine emergency
  • Pain or discomfort — arthritis, an injury, or stomach upset can all cause panting that's worse when a dog is lying still, since there's nothing to distract from the discomfort
  • Heatstroke — a genuine emergency if a dog has been in a hot room or car and is panting heavily alongside drooling, vomiting, weakness or confusion

Reading the Pattern: What Makes This Different From Daytime Panting

The context matters more than the panting itself. A dog panting after a walk, in a hot room, or during a thunderstorm is behaving completely normally. What's genuinely not normal is a calm, resting dog — not hot, not stressed, not recently exercised — panting persistently once settled for the night. That specific pattern, in an otherwise resting dog, is the one worth taking seriously rather than assuming it will pass.

Does Breed Make a Difference?

Brachycephalic (flat-faced) breeds — Bulldogs, Pugs, French Bulldogs, Boston Terriers and similar breeds — have a narrower airway to begin with, so they naturally pant more heavily and more often than other breeds, including at night, simply to move enough air. This baseline needs to be factored in before assuming something's wrong: a Bulldog panting more than a Labrador isn't automatically a red flag. That said, brachycephalic breeds are also more prone to genuine respiratory problems (brachycephalic obstructive airway syndrome), so a real change from that dog's own normal — noticeably worse than usual, or new noisy or laboured breathing — is still worth a vet check rather than being written off as "just how the breed is." Large and giant breeds are also somewhat more prone to heart conditions that can show up as night breathing changes, which is another reason breed context is worth keeping in mind alongside the pattern itself.

Keeping Track Helps Your Vet

If night panting isn't clearly explained by heat or a one-off trigger, a few days of simple notes make a real difference at the vet visit: roughly when it happens, how long it lasts, whether your dog seems distressed or just restless, and anything else going on — thirst, appetite, mobility, mood. A short video on your phone of an episode is genuinely useful too, since panting and breathing patterns are hard to describe accurately from memory and can look different by the time you're in the consult room. This kind of detail often speeds up getting to the right cause rather than needing a longer diagnostic process to rule things out one by one.

What You Can Do at Home

For heat-related panting, a cooler room, less bedding, and good airflow usually solve it quickly. For anxiety-driven panting around specific triggers like fireworks or thunderstorms, a calm, familiar space and a consistent evening routine help; our guide to calming treats that actually work covers options worth considering for a dog with a clear pattern of situational anxiety. For suspected sundowning, keeping a stable routine, reducing bright lighting in the evening, and avoiding disruptive changes to the home environment can genuinely help some dogs, alongside whatever your vet recommends after an assessment. None of this applies to panting with any of the medical red flags below — those need a vet, not a home adjustment.

When to See a Vet

  • Persistent panting in a calm, resting dog with no obvious trigger (heat, exercise, stress)
  • Panting alongside coughing, laboured breathing, or blue/purple/grey gums or tongue — treat this as an emergency
  • Panting alongside increased thirst, increased appetite, or hair loss (possible Cushing's)
  • Panting that seems linked to pain — reluctance to move, limping, a hunched posture
  • New night restlessness, pacing, or confusion in an older dog alongside the panting (possible cognitive dysfunction)
  • Any signs of heatstroke — heavy panting with drooling, vomiting, weakness, or confusion after heat exposure

FAQ

Why does my dog pant at night for no reason?

It's often heat, leftover excitement, or mild anxiety. In older dogs, unexplained night panting alongside restlessness or pacing can be a sign of sundowning, part of canine cognitive dysfunction, and is worth mentioning to your vet.

What is sundowning in dogs?

Sundowning is restlessness, confusion, and disrupted sleep that specifically worsens in the evening and night, part of canine cognitive dysfunction syndrome (the canine equivalent of dementia), which becomes increasingly common with age.

Is night panting a sign of a heart problem in dogs?

It can be. Heart conditions like mitral valve disease can cause laboured breathing that's worse at night or lying down, often with a cough. This needs a vet check rather than waiting it out.

How common is cognitive dysfunction in older dogs?

It's common and increases significantly with age. A study of 325 geriatric dogs (aged nine and over) found signs of cognitive impairment in 22.5% of them — roughly one in four to five — with females and neutered dogs significantly more affected than males and entire dogs.

When is dog panting at night an emergency?

When it comes with blue, purple or grey gums, collapse, continuous panting while fully at rest, or signs of heatstroke like drooling, vomiting and confusion. These need immediate veterinary attention.

Sources

This article is for general information only and isn't a substitute for veterinary advice. If your dog's night panting is persistent, unexplained, or paired with other symptoms, please contact your vet.

Related: More Senior Dog Guides