Paging Dr Doggo

Your pup may know you’re sick before you do

31 October 2023

You’re lying on the sofa under your heaviest blanket. Your energy is low. You feel a little off. Your pup snuggles up to you like they know something is wrong. Then, the following day, you wake up with the flu.

If it ever seems that your dog has the uncanny ability to tell when you’re sick, it’s not all in your (stuffed-up) head. From reading body language to actually sniffing out disease, dogs have several ways they can pick up on illnesses. We did a little digging, including checking in with Dr Glen Golden – a research scientist at Colorado State University’s Department of Biomedical Science – to find out just how far a dog’s detection skills go.

Let’s start with a dog’s most impressive tool: their nose. A dog’s sense of smell is between 10,000 and 100,000 times better than a person’s. That’s a lot. But what does a keen sense of smell have to do with telling when someone is sick?

“Since Hippocrates, it has long been speculated that diseases might be diagnosed based on odour,” says Dr Golden. “Over the last decade, studies have shown that the volatile organic compounds (VOCs) found in urine, faeces, breath or other bodily emanations have been successfully used to detect disease or infection. This has led researchers to conclude that VOCs found in waste are a window into the body.”

Dogs are skilled sniffers

We know dogs can learn to detect various diseases, including diabetes and breast cancer, by sniffing urine, sweat and breath. But sometimes, dogs pick up on conditions or medical events for reasons that are less clear.

Dr Golden explains: “We know dogs can respond to an oncoming epilepsy event or a PTSD fugue state. But what, exactly, they are responding to isn’t definitively known. There is some evidence to suggest that, in the case of epilepsy, dogs are responding to a certain odour. However, it hasn’t been proven that odour is the only thing driving the response. With PTSD, there’s strong anecdotal evidence that dogs are responding to a variety of stimuli, including human micro-expressions and body language.”

This means dogs’ ability to detect illness goes beyond their sense of smell. Since the average dog hasn’t been trained to alert people to the presence of diseases, the reason your dog seems to know when you’re sick probably has little to do with odour – and a lot to do with their relationship to you.

But they shouldn’t replace doctors

Your dog knows you – your body language, your behaviours and your routines. They’re also very good at reading moods and picking up on changes to the norm. Take facial expressions, for example. Dogs can recognise when you’re mad, relaxed, happy or down. And research has also shown that they can pick up on (and respond to) emotional cues by listening to changes in a person’s voice. So, if something is a little off with you, chances are your dog will know it.

At this point, you may be wondering, if dogs are so great at identifying when someone isn't well, will they ever play an everyday role in human healthcare? According to Dr Golden, we shouldn’t hold our breath for the day dogs show up in hospital as part of, say, a routine dermatology screening.

“Dogs have been shown to use their noses to reliably detect melanoma, but that doesn’t mean our canine friends are likely to be used in place of lab tests,” says Dr Golden. Instead, researchers are working to better understand how a dog’s (or other mammal’s) nose can be so much more sensitive than current medical testing.

So, dogs won’t be used in the average GP’s office. But what if you could train your own dog to pick up on certain conditions and use them as a warning system for oncoming illnesses? With patience and proper training techniques, this might be possible. But just because a pet parent can potentially train their dog to alert them to certain stimuli doesn’t mean they should. Dr Golden warns that “training a dog to alert you to an oncoming migraine, for example, could result in complacency over a dangerous situation, or cause you to ignore other symptoms that would be best detected by a medical doctor”.

In other words, people with medical degrees are still important; your first port of call should never be your dog. But that doesn’t mean we can’t appreciate the extra attention our furry friends give us when we’re under the weather. They still make the best – and cuddliest – nurses around.

Kate Sheofsky

Kate Sheofsky hails from San Francisco, where she developed a love of writing, Giants baseball, and houses she can’t afford. She currently lives in Portland, OR, and works as a freelance writer and content strategist. When not typing away on her laptop, she enjoys tooling around the city with her two rescue pups searching for tasty food and sunny patios.