Dogs have an incredible intuition when it comes to reading the emotions of their owners. But that isn't the limit of their abilities when it comes to figuring out what's going on in our minds or our bodies.

According to one study that was carried out by Lincoln University, in the United Kingdom, dogs can detect when their owners show a range of feelings. Your dog probably already knows precisely when you are feeling sad, happy, or experiencing loneliness.

But what about when you're ill? Largely thanks to their sense of smell, dogs can actually work out when we're sick or becoming sick, sometimes before symptoms have even hit us.

Well… I just gave the flower to my dog and he did it.
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How Dogs Know When You're Sick

A canine's sense of smell is incredible and far more impressive than our own. Experts say that their sense of smell is around 1,000 to 10,000 times more powerful than a human's. Some sources put that number between 1,000 and 100,000!

Of course, you've likely seen this talent at work whenever you've cracked open a food packet; your dog probably appears as if out of nowhere. They do have a unique ability to pick up a trail from a long distance.

But this keen sense of smell means that your pup can also tell when you're feeling under the weather. According to research, dogs can detect VOCs, or volatile organic compounds. These are present in our body when we become unwell, including in major illnesses like cancer.

Similarly, our hormones and other brain chemicals are constantly in flux depending on our emotions. Serotonin, dopamine, and oxytocin levels all decrease during bouts of illness, and your dog can detect these invisible changes. They could even notice an oncoming cold before you feel the symptoms!

It's not just changes in body chemistry that signal illness to your dog, though. We're all familiar with the lethargy, low mood, and reduced activity that comes with sickness. When your dog notices these changes in your behavior and body language, they'll know that you're becoming unwell.

Photographed this beautiful dog named Dolly for a volunteer run initiative called PixelPaws which aims to help dogs find their forever homes through photography.

This dog was available for adoption through LEASH Animal Welfare Society, which is an incredible dog rescue organization serving Greater Vancouver in rescuing/rehoming dogs in need.

Behavior Changes When a Dog Knows You're Sick

In addition to sensing chemical changes in our bodies, dogs can read the body language and subtle facial expressions that accompany the human range of emotions. If you're suddenly marching or banging around the house, speaking in a deeper tone of voice, and have a frown on your face, pretty much anybody would know you're angry.

Dogs (and cats) have a much deeper intuition, being able to pick up on the subtlest of signs. This includes if you're feeling down in the dumps, lonely, or even stressed. You might not even realize that you're putting a negative vibe out there, but your dog will.

When we become ill, we show similar kinds of behavioral changes. We might spend longer in bed, trudge around the house with our head dipped, cough and sniffle, and so on. All of these signs - and more - can tell your dog that you're not feeling well.

So, when your dog picks up on your discomfort, what changes might you expect to see in their behavior? There are subtle behavioral signs that you can watch out for in your dog should you become unwell again. Your dog might know that you're becoming sick if they're:

  • Staying by your side: Your pup might become more clingy and affectionate, sticking by your side much more than usual.
  • Lying down with you: Your dog might join you on the couch or in bed, even if they wouldn't ordinarily do so. They like to be close to you when you're feeling unwell.
  • Showing less energy: They may be calmer and quieter than usual, barking less or running around the house less than usual.
  • Less eager to walk: If your dog isn't pestering you for his or her usual walk, it could be a sign of sympathy, as they know that your energy levels are lower than usual.
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Can You Train Dogs to Sense Sickness?

The good news is that dogs' innate sense of smell doesn't require any training. Your average, day-to-day canine will already be able to sense when you're ill and comfort you in all of the ways we've outlined above.

That said, there is specialized training for dogs that can help them to sense a more serious illness in their owner. Many service dogs go through this training to become medical detection dogs, allowing them to detect conditions like diabetes and cancer.

Diabetes detection dogs can sense when an owner's blood sugar is too low, then signal to the person that they need to take action. Cancer detection dogs start their training with blood samples, learning how to detect when certain types of cancer are present.

Some dogs can even be trained to sense when a heart attack or seizure is going to happen. These dogs can help their owners to get help or remove themselves from dangerous situations before an attack occurs.

Listen to Your Dog (and Your Body)

It's incredible that our pups can pick up on things that are invisible to us, and if you notice some of the behavioral changes outlined above, it might be time to stock up on Vitamin C; it could just shorten that bout of flu!

Of course, it's no replacement for seeing a doctor if there are symptoms you're concerned about. Equally, if your pup's suddenly showing a lot more interest in you, don't throw all your money at expensive healthcare bills - they could simply want some attention! Remember to trust your body and do what feels right.