You Can't Predict This Medical Emergency, but These Dogs Sure Can

Written by Dr. Karen Shaw Becker

diabetic alert dog

Story at-a-glance -

  • Dogs are truly man’s (and woman’s) best friend, and they prove it every day in their willingness to use their unique skills to benefit humanity
  • One example are medical detection dogs, specifically diabetes service dogs who’ve been improving the quality of life for Type 1 diabetes patients for years
  • Medical response dogs are trained to alert their owners once they show symptoms of low blood sugar
  • Diabetic alert dogs are trained to pick up changes in their owners’ blood chemistry and alert before symptoms appear
  • Researchers in the U.K. have discovered what the alert dogs sense when a person’s blood sugar dips — it’s a chemical in human breath called isoprene

It seems the sky's the limit when it comes to the ways in which our canine companions help us, both through the bond we share with them and their innate ability to sense things we cannot. Not only do dogs offer us companionship, friendship and comfort, but they also work beside our military and law enforcement officers and in a wide variety of other important roles assisting humans, including medical detection work.

In fact, for years diabetes service dogs have worked with people with Type 1 diabetes who experience hypoglycemic unawareness, meaning they do not sense that their blood sugar is dropping rapidly or is dangerously low until they have symptoms such as stomach cramping, nausea, dizziness and even seizures.

Diabetes Dogs Accurately Detected Blood Sugar Changes 83 Percent of the Time

Research conducted in the U.K. a few years back and published in the journal PLOS ONE, evaluated the accuracy of dogs trained to detect hypoglycemia (low blood sugar) in people with Type 1 diabetes.1

For the study, the University of Bristol research team collaborated with a U.K.-based organization that trains dogs for medical detection purposes. The dogs recruited for the study were owned by people with Type 1 diabetes, and all were specially trained to detect the smells associated with a drop in blood sugar and to alert their owners.

There were 10 breeds/breed mixes represented, including Labrador and Golden Retrievers, Lab/Golden crosses, Poodles, Collie crosses, Labradoodles, Lurchers, Cocker Spaniels and Yorkshire Terriers.

The researchers looked at 12 weeks' worth of blood sample records from the diabetic patients, as well as reports of all the instances in which the dogs alerted them of an impending hypoglycemic episode. In over 4,000 instances of hypo- and hyperglycemic episodes, the dogs correctly warned their humans 83 percent of the time.

"We already know from previous studies that patients' quality of life is vastly improved by having a medical detection dog," study co-author Nicola Rooney, Ph.D. told MedicalNewsToday. "However, to date, evidence has come from small-scale studies. Our study provides the first large-scale evaluation of using medical detection dogs to detect hypoglycemia."2

Medical Detection Dogs Offer Natural, Noninvasive, Proactive Solutions

The study authors emphasize that dogs who will be used to detect blood sugar fluctuations must receive professional training. Equally important is the relationship that develops between the human diabetes patient and his or her dog.

"Since the usage of such dogs is growing," explains Rooney, "it's important that any dogs used for these purposes are professionally trained, matched, and monitored by professional organizations like Medical Detection Dogs. It's also vital that research continues both to assess true efficacy and determine ways to optimize their performance."

Medical Detection Dogs also provides specially trained dogs to people with other types of medical conditions as well.

"Our dogs … serve the wider medical community by offering proactive solutions that are natural, [noninvasive], and have been shown to provide countless psychological benefits," says Claire Guest, co-founder of the organization. "As our natural companions, and with a highly refined sense of smell, why shouldn't they be able to detect changes in our personal health?"3

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How Do Diabetes Dogs Know When Blood Sugar Levels Drop?

As mentioned above, diabetes service dogs are trained to recognize symptoms of dropping or too-low blood sugar and alert their humans in time to avoid a medical emergency, called a hypoglycemic attack or "hypo." These specially trained dogs are often able to help people with Type 1 diabetes live a normal, active life.

So, how do the dogs do it? What is it they sense or smell when a person's blood sugar is plummeting? This question has baffled scientists for years, but another team of researchers in the U.K. thinks they may have found the answer.

Their findings, which were published in 2016 in the American Diabetes Association journal Diabetes Care, suggest the dogs smell a common natural chemical found in exhaled human breath called isoprene.4 Humans are unaware of the odor of isoprene, but dogs, with their keen sense of smell, can pick it up. According to study co-author Dr. Mark Evans of Addenbrooke's Hospital, University of Cambridge:

"Isoprene is one of the commonest natural chemicals that we find in human breath, but we know surprisingly little about where it comes from. We suspect it's a by-product of the production of cholesterol, but it isn't clear why levels of the chemical rise when patients get very low blood sugar."5

For the study, which was performed in a carefully controlled setting, the researchers lowered the blood sugar levels of a group of volunteers with Type 1 diabetes while using special equipment to detect the presence of certain chemicals in their breath as they exhaled.

The scientists observed that isoprene levels were significantly elevated while the women were experiencing hypoglycemia. In some of the volunteers, the isoprene level almost doubled. The researchers hope their study results can be used to develop new tests for detecting hypoglycemia and reduce the risk of potentially life-threatening complications for people with diabetes.

How Diabetes Service Dogs Help Their Owners

There are actually two different types of diabetes service dogs. There are medical response dogs, and diabetic alert dogs. Medical response dogs are trained to alert their owners once they show symptoms of low blood sugar.

Diabetic alert dogs, on the other hand, are trained to pick up changes in their owners' blood chemistry, and then alert either their owners or caregivers to take action. Typically, there is a 15- to 30-minute window in which to treat a low blood sugar situation before the person starts to experience symptoms. There are a number of behaviors the dogs can be trained to perform to alert their humans, for example:

  • Sitting and staring at his owner
  • Touching his owner with his nose
  • Holding a small, soft toy in his mouth that is always hanging from his collar Jumping up and putting his paws on his owner's shoulders

The dogs might also be trained in other assistance behaviors, including getting the attention of another family member if his owner needs help, bringing objects to his owner (e.g., medications), fetching the owner's cell phone and even dialing 911 himself, using a special device.