Dogs’ Sixth Sense: detecting disease

Man’s best friend is known for loyalty, playfulness, and an uncanny ability to sense our emotions. But did you know that dogs can also detect certain medical changes in humans? From smelling the onset of a seizure to detecting diseases, our canine companions never cease to amaze us with their heightened senses. While all dogs have an impressive olfactory system compared to humans, certain breeds are particularly renowned for their extraordinary scenting abilities such as Bloodhounds, Basset Hounds, Beagles, German Shepherds, Pointers and Labrador Retrievers to name a few.

Beyond their functional roles, a dog’s sense of smell plays a crucial part in how they perceive the world, interpret their surroundings, and communicate with other dogs. Their noses provide a window into a world that remains largely mysterious and inaccessible to humans, making their sense of smell a true canine superpower.

Ways dogs signal disease

Dogs are deeply attuned to their human companions. They have evolved alongside humans for thousands of years, honing an exceptional ability to detect shifts in our behaviours, emotions, and even physical health. When an owner is experiencing health issues, whether acute or chronic, many dogs will display noticeable behavioural changes in response. Here are some common behavioural shifts observed in dogs when their owners face health challenges:

• Increased Clinginess or Attachment: Dogs may sense their owner’s vulnerability or distress and respond by becoming more attached. They may follow their owner around more than usual, sit closer to them, or even act as a ‘guard’ by their side.
• Anxiety or Restlessness: Noticing a difference in their owner’s demeanour, routine, or even scent can make dogs anxious. They might pace, whine, or bark more than usual. This is particularly common if there are sudden changes in the home environment, such as medical equipment or frequent visits from medical professionals.
• Depression or Lethargy: Some dogs may pick up on their owner’s physical or emotional pain and mirror it by becoming subdued, less playful, or lethargic.
• Protective Behaviors: Dogs may exhibit increased protective behaviours, such as growling at strangers, placing themselves between their owner and others, or displaying territorial behaviours, especially if they sense their owner is in a weakened state.

• Toileting Accidents: Disruptions in a dog’s routine or increased stress due to their owner’s health issues can lead to accidents in the house, even in house-trained dogs.
• Attention-Seeking Behaviors: Feeling a lack of attention or sensing a shift in their relationship with their owner, a dog may engage in behaviours designed to draw attention, like barking, whining, or bringing toys to the owner repeatedly.
• Changes in Eating Habits: Dogs might display changes in their eating habits, ranging from reduced appetite to overeating, possibly mirroring the stress or changes they sense in their environment.
• Regression in training: Regression in training is a multifaceted issue, rooted in changes to routine, communication, emotional stress, and more. Disruption in a dog’s routine can create confusion and uncertainty, leading the dog to revert to previous behaviours. In addition to this; lack of proper exercise and mental engagement which often occur when owners are unwell or pregnant can lead to restlessness and behavioural issues, including regression in training. Lastly, if the owner was the primary person reinforcing good behaviour and they’re now less able to do so, the dog may gradually revert to old habits. Training is typically maintained through consistent reinforcement.

Diseases dogs can detect

Neurological Changes: When a Dog Senses a Stroke or Seizure

While the exact mechanisms remain a topic of research, it’s believed that dogs can sense alterations in a person’s behaviour, body language, or scent caused by physiological changes preceding a stroke. This remarkable sensitivity, combined with their deep bond with humans, positions dogs as potential life-saving companions, alerting individuals and their families to seek medical attention promptly. The aftermath of a stroke manifest as subtle changes in movement, speech, or behaviour, all of which your dog notices. 

In cases of seizures, many stories highlight dogs alerting their owners moments before an episode begins. Some dogs have even been trained specifically for this purpose, proving the depth of their sensory perception.

Detecting Diabetes: A Dog’s Nose Knows Blood Sugar Levels

A sudden spike or drop in blood sugar can produce specific scents, thanks to chemicals like isoprene present in the human breath. Some dogs, even without training, will display distinct behaviour when they sense these changes, such as:

• Licking the person’s face.
• Becoming restless or anxious.
• Pawing or nudging the individual.

Given this innate ability, there’s a growing trend of training dogs to assist diabetics, helping them manage their condition more effectively.

Cancer Detection: Can Dogs Smell the Big ‘C’?

Perhaps one of the most fascinating areas of research is whether dogs can detect cancer. Preliminary studies and anecdotal evidence suggest that dogs might be able to smell certain types of cancer, such as:

• Lung cancer
• Breast cancer
• Melanoma
• Prostate cancer

While more research is needed, the potential of dogs in early cancer detection showcases their incredible olfactory prowess.

Parkinson’s: Sniffing It Out Before Symptoms Show

Research has indicated that people with Parkinson’s disease produce a distinct, subtle scent linked to certain compounds present in sebum — an oily substance that coats the skin. Even in the early stages of the disease, before overt symptoms manifest, these chemical changes can be present. Trained dogs have demonstrated the ability to identify this specific scent from skin swabs, showcasing the potential for early detection. This remarkable capability not only underscores the depth of dogs’ sensory skills but also offers promising avenues for non-invasive early diagnostic techniques in the medical world.

Mood: Our Emotional Barometers

Dogs are exceptionally attuned to our emotions. When an individual is grappling with depression, anxiety, or other mood disorders, their dog can often sense emotional turbulence. Responses can include:

• Increased affection or closeness.
• Displaying comforting behaviours like resting their head on the person’s lap.
• Offering distractions by bringing toys or initiating play.

While we’ve always cherished the emotional bond we share with our dogs, understanding their ability to detect medical changes adds another layer of appreciation. Recognising these subtle signals from our dogs not only strengthens our connection with them but can also save us from potential harm. The bond between humans and dogs will only strengthen over time.