Why harnesses are safer when walking a dog

Do you walk your dog on a collar or a harness? Here are five reasons why the latter option is more effective, more secure, and safer for your pup.

Dog harnesses are increasingly common, but many pets are still walked on a traditional collar. Unfortunately, studies have shown that it can be dangerous to attach a leash to a flat collar. Here are five reasons why a harness might be a safer choice.

1. Harnesses protect your dog’s trachea

Flat collars put direct force onto the dog’s throat, including the delicate trachea. Aside from being uncomfortable, this can cause severe damage to the neck.

Collars are particularly dangerous if your dog is a puller or jerks the leash. In some cases, strong pulling can even lead to tracheal collapse. Trachea damage is more likely in small dogs or puppies, as they have weaker neck muscles, but it can happen to any dog. Brachycephalic breeds that have trouble breathing, such as pugs or bulldogs, are at even greater risk of the constriction of collars.

In contrast to collars, harnesses spread pulling force across the dog’s shoulders and chest. They also tend to sit lower on the dog’s chest, so there’s much less chance of neck damage.

2. Harnesses may prevent thyroid damage

The thyroid gland is located at the front of the neck. It releases hormones that affect everything from a dog’s digestive system to his mood, so it can cause havoc if it isn’t functioning correctly.

Unfortunately, collars can place force directly onto the delicate thyroid gland. This has the potential to cause inflammation in the thyroid, which can lead to an immune system response. There’s also the risk of severe and chronic damage to the gland, especially if your dog is a strong puller.

Thyroid damage is more likely when using aversive collars, such as a choke chain or prong collar – neither of which should ever be used on dogs. That said, damage can also occur even if your dog is just wearing a regular flat collar. Harnesses are much less likely to cause thyroid damage – even if your dog pulls.

3. Harnesses prevent neck and back strain

Collars force the dog’s neck into an unnatural position when he pulls. As the neck is part of the spine, this can also put strain on the back muscles and spinal column.

Over time, pulling on a collar can lead to muscular injuries, bulging spinal discs, and chronic pain. As harnesses sit lower on the dog’s chest, the neck remains in a more neutral position.

4. Harnesses may lower the risk of eye glaucoma

In a 2006 study, researchers measured the intraocular pressure of dogs who pulled on either a harness or collar.

They found that the pressure inside the eye increased when dogs were wearing a collar, but not a harness. For this reason, dogs that are susceptible to eye glaucoma or other eye conditions should always wear a harness.

5. Harnesses make it harder to slip out

Some dogs learn how to “back out” of a collar. This is particularly common in dogs with a thick neck and relatively small head, such as the German shepherd. Once free, the dog could be in danger from other dogs, cars, or getting lost.

It’s much more difficult to slip out of a harness. Some harnesses even have two belly straps for extra security. If your dog is an escape artist, a harness is an essential purchase.


A dog harness is a safer option for attaching a leash during a walk. Properly fitted harnesses spread pulling force across the chest and shoulders, rather than the delicate neck. They are also more secure and provide extra control.

Collars are still important for an ID tag though, so your dog should wear both on a walk. Unlike harnesses, which should only be worn during activities, collars can be worn for long periods, making them a great tool for displaying identification!


Richard Cross has been writing about dogs for over 10 years. He's currently editor of The Dog Clinic, a website dedicated to positive training methods. When he's not writing, Richard enjoys long walks with his beloved Labrador and golden retriever.