• Posted December 18, 2023

Fatigued 'Frenchies': Flat-Faced Dogs Get Worse Sleep

French Bulldogs might be the most widespread breed in the world, but the fancy, flat-faced pooches pay a high price for their popularity, a new study warns.

The shortened skulls and large, round heads that make Frenchies so cute also leads to worse sleep, thanks to breed-specific sleep apnea, researchers report.

Further, this poor sleep could be a sign of potentially harmful changes in brain function, said researcher says Enikő Kubinyi, a professor of ethology at Eötvös Loránd University in Budapest, Hungary.

Brain wave readings taken as the dogs sleep indicated patterns associated with loss of white matter -- the nerve fibers that relay signals between different parts of the brain.

"They have large heads and eyes, high foreheads and small noses because we humans find these traits irresistibly attractive. That's how babies get us to care for them," Kubinyi said in a university news release. "It is possible that the selection of dogs to be infant-like in appearance has also infantilized their brain function."

Extremely flat-faced canines like pugs or French and English bulldogs -- described as brachycephalic breeds -- tend to have lives 3 to 4 years shorter than other breeds, and they often do not survive to adulthood, researchers said in background notes.

During their short lives, they are also prone to many ailments, often needing surgery to fix problems with their eyes, respiration or musculoskeletal systems.

The abnormal shortening of the breeds' skulls have been associated with a distorted, rounded brain, researchers said, but no one's yet figured out how this might affect their brain function.

For the study, researchers studied the sleep of 92 family dog using EEG brain scans.

The dogs spent about three hours in the sleep lab with their owners. While the pooches slept, researchers took brain readings through electrodes glued to their scalps.

"We wanted to investigate whether flat-faced dogs sleep differently from other dogs, as they are known to suffer from oxygen deprivation due to respiratory problems and therefore have poorer quality sleep,"said researcher Zsofia Bognar, a doctoral student with Eötvös Loránd University.

"We found that the flat-faced dogs slept more in the three hours given to them during the study,"Bognar added. "More daytime sleep is probably compensation for insufficient sleep at night."

Researchers focused on the REM phase of the dogs' sleep, since it features high-frequency brain activity similar to wakefulness and is associated with learning success in dogs.

They found patterns of REM sleep that have already been associated with poorer learning in dogs and loss of brain white matter in humans, researchers said.

The study was published recently in the journal Brain Structure and Function.

"It seems as if the flat-faced dogs have retained the sleep pattern of puppyhood, similarly to newborns who spend more time in REM sleep,"Kubinyi said. "What is very likely"¦ is that breeding for brachycephalic heads leads to potentially harmful changes in brain function."

More information

The American Kennel Club has more about brachycephalic dog breeds.

SOURCE: Eötvös Loránd University, news release, Dec. 13, 2023