French Bulldog or Pug harness: why choose it over a collar?

Bouledogue français bringé en harnais, gueule ouverte, debout sur une allée pavée près d’un banc de parc

For a French Bulldog, a Pug or an English Bulldog, it is better to clip the lead to a well-fitted harness than to a collar: the PDSA and the RSPCA, two major UK animal welfare charities, both advise it, because pressure on the neck can make breathing problems worse in these short-nosed dogs. The harness still has to be right for a French Bulldog or Pug: a front strap that rides up onto the throat, or a walk in the heat of the day, cancels out part of the benefit.

Why is the neck of a short-nosed dog so sensitive?

Brachycephalic breeds have a short skull and a flat face. In many of them, the tissues of the nose, throat and larynx obstruct the flow of air: this is brachycephalic obstructive airway syndrome, or BOAS. The PDSA lists the Pug, French Bulldog, British Bulldog, Shih Tzu, Pekingese and Boston Terrier among the breeds commonly affected.

The BOAS Research Group at the University of Cambridge points out that a dog with a normal upper airway breathes quietly: snoring and snorting are signs of obstruction. In some moderately affected dogs, these signs only appear during exercise or excitement. The PDSA also lists excessive panting even at rest, being unable or unwilling to exercise, and struggling in hot weather.

With airways that are already narrow, every extra constraint counts, so the question “Pug: harness or collar?” has a clearer answer than for most other breeds.

Harness or collar for a French Bulldog: what the sources say

The advice is consistent:

  • The PDSA advises attaching the lead “to a well-fitted harness instead of a collar as pressure on their neck can make breathing problems worse”. It adds that a harness helps the dog pant and cool down.
  • The RSPCA recommends walking a brachycephalic dog on a harness rather than a collar and lead, “to avoid putting pressure on their neck”.
  • The UK Kennel Club, in its advice after BOAS surgery, also recommends a harness instead of a collar to avoid putting pressure on the airway.

Two studies provide figures, with their limitations. Carter, McNally and Roshier (2020, Veterinary Record) measured the pressure exerted by seven collars and a slip lead on a plastic neck model: between 83 and 832 kPa depending on the collar and the force applied through the lead. No collar tested gave a pressure low enough to mitigate the risk of injury when the dog pulls. Limitation: an inanimate model, not specific to short-nosed breeds.

Bailey, Packer and Wills (2025, Veterinary Medicine and Science) compared a flat collar and a Y-shaped harness in 10 brachycephalic and 10 long-nosed dogs. In the brachycephalic dogs, the collar raised the pressure inside the eye as soon as the lead was held taut while standing still, and more so during walking; the harness did not change it in either group. However, the breathing rate of the brachycephalic dogs rose during walking with both the collar and the harness: a harness does not remove the breathing effort that comes with exercise. Limitations acknowledged by the authors: 20 dogs, a partly subjective breathing measurement, a single session.

For the general comparison, valid for all breeds, see our article harness or collar: which to choose.

Harness for a brachycephalic dog: 5 points to check

1. The front strap sits low, on the chest

The strap across the front of the dog should rest at the base of the neck, on the top of the breastbone, never on the throat. A harness whose front strap rides up towards the windpipe as soon as the lead tightens partly recreates the effect of a collar. Gently tension the lead: if the strap rides up, adjust the neck strap or try a different shape. Our article on Y-shaped or H-shaped harnesses explains how to check where this strap runs.

2. A fit suited to a thick neck and a broad chest

Bulldogs often have a thick neck and a broad chest, which can put them between two sizes. Choose the size by chest girth, measured just behind the front legs; weight is only a guide. If the neck and chest point to different sizes, read how to choose between two harness sizes. Straps that adjust separately at the neck and chest make fitting easier: this is the case for the models in our harness collection, with its size guide.

3. Two fingers under each strap

A harness that is too tight squeezes the ribcage; too loose, it slips and twists. Two fingers should slide flat under each strap. The belly strap must not rub in the armpits. Check again after any change in weight.

4. No constant pulling

A dog that pulls all the time works harder. A front attachment can help, as long as the harness stays centred, but it is loose-lead training that really solves the problem.

5. Calm fitting

Excitement causes panting: a harness that opens with buckles avoids forcing it over a broad head. Our step-by-step method: how to put a harness on your dog.

Heat and exercise: the harness is not enough

Hall, Carter and O’Neill (2020, Scientific Reports) reviewed the records of 905,543 dogs under primary veterinary care in the UK in 2016 (VetCompass programme): 395 confirmed cases of heat-related illness, 14.18% of them fatal. Brachycephalic dogs had about twice the odds (odds ratio 2.10) of medium-nosed dogs. Compared with the Labrador, the odds were almost 14 times higher for the Bulldog (13.95), 6.49 times for the French Bulldog and 3.24 times for the Pug. In a second analysis of the same data (Hall et al., 2020, Animals), exercise was the trigger in 74.2% of events, against 5.2% for confinement in a vehicle.

According to the Cambridge group, dogs with BOAS cannot lose heat as easily as healthy dogs when their body temperature rises during exercise. A few rules follow:

  • In hot weather, go out early in the morning or late in the evening and keep walks short (PDSA).
  • Slow down and let your dog rest if they are struggling to breathe (PDSA, Kennel Club).
  • Choose regular, steady exercise, which the RSPCA considers the best way to reduce problems. For how long, see how long to walk your dog each day.
  • Watch their weight: according to the PDSA, the RSPCA and the Kennel Club, extra weight makes breathing problems worse.
  • In strong heat, shorten the walk rather than relying on the harness: a chest plate, even a mesh one, covers part of the chest.

A short-nosed dog that refuses to walk on may be too hot or out of breath: our article dog refusing to walk on a walk helps you work out why.

Signs that mean the walk should stop

Stop in the shade and call your vet if you see laboured breathing, panting that does not settle, blue-tinged, bright red or very pale gums, heavy drooling, vomiting or weakness. For the PDSA, heatstroke or a sudden increase in breathing difficulty is an emergency. In case of heatstroke, it advises gently pouring cold water (cold tap water is fine) over the dog’s whole body, not covering them with a wet towel, and calling the vet as soon as possible.

If your dog snores, gets out of breath quickly or copes badly with heat in everyday life, talk to your vet. A harness makes walks more comfortable; it does not treat BOAS.

Frequently asked questions

Can a French Bulldog wear a collar?

Yes, to carry an ID tag for example, but the PDSA and the RSPCA recommend clipping the lead to the harness.

Which harness for a Pug?

There is no universal model: look for a front strap that stays on the chest, adjustment at the neck and chest and easy fitting, then measure your dog. Without a tape measure, follow our method to measure your dog without a sewing tape.

Does a harness prevent heatstroke?

No. According to the PDSA, it makes panting easier, but only a suitable walk (cool hours, slow pace, breaks in the shade) reduces the risk.

Sources