Diabetic alert dogs (D.A.D.s) are trained to detect low blood sugar levels in their owners with diabetes. Guided by their strong sense of smell, D.A.D.s alert to dropping numbers, often before any outward signs of a low appear.

Sniffing out lows may seem like a superpower — so how exactly do these heroic dogs do it? We asked Dr. Dana Hardin, M.D., a leading D.A.D. researcher, to give us a glimpse into the science.

A Nose for Lows

Dogs detect more smells than we do — and they may be better at analyzing them too. A dog’s nose contains upward of 300 million olfactory (scent) receptors, compared to about six million in human noses. Proportionally speaking, the part of a dog’s brain that is devoted to analyzing smells is 40 times greater than our own!

So when it comes to lows, while our noses can’t detect anything, D.A.D.s can and do smell something different. “The dogs are detecting VOCs — volatile organic compounds — contained within the breath,” explains Hardin. Her research has found that during an episode of hypoglycemia, the breath of someone with type 1 diabetes changes to contain a certain “signature” of VOCs that is different from when the same person is not having a low.

By using their superior scent-detecting abilities, dogs can be trained to key in on the scent of these VOCs in a person with diabetes and act upon what they detect by performing a predetermined alert task, such as persistent nudging, lying down, or putting their paw on a shoulder.

How D.A.D.s Are Trained

To become attuned to the scent of a low, “dogs go through general training until they become reliable to alert to any low they smell,” notes Hardin. When they are assigned to a person, “the dogs are trained again for that person’s specific scent.”

This training may involve the child or adult with diabetes providing a perspiration sample from a time when blood sugar was at or below a certain low threshold. (The person with diabetes may also be asked to blow into a bag to create a breath sample.) Trainers use the sample to play scent detection games with the dog and provide other opportunities for the dog to hone its skills. Other training includes learning advanced obedience commands for working service dogs.

Next, the dog and the person with diabetes meet to become acclimated to each other. During this trial period, the dog’s alerts are double-checked with a glucometer. The dog is not sent home with its new family until the dog reliably works well for the person with diabetes and the family demonstrates good ability to maintain the dog’s training. The dog’s personality also needs to align with the new owner’s expectations and lifestyle, and sometimes during the acclimation period it’s determined that a different D.A.D. may be a better fit.

Helping D.A.D.s Do Their Job

To do their jobs well, D.A.D.’s require “off duty” time too to eat, sleep, and unwind. “If it’s a D.A.D. for a child with type 1, the new owners cannot ask the D.A.D. to go to school all day, be on duty after school, and then be on duty overnight,” explains Hardin. “Just like people, the dog needs time off. If proper time off is not given, the dog can become fatigued, and that can affect its ability to detect. This is why, when someone wants to obtain a D.A.D., it’s really important to find out what will be the most important parts of the day for the dog to do detections and go from there.”

Hardin also cautions that even the most well-trained on-duty service dogs will have the occasional dogs-will-be-dogs moment. “Things can happen, like a dog being distracted by mylar balloons at a birthday party or becoming distracted walking on the beach if that’s a different environment for the dog,” says Hardin. Human handlers and owners should be aware of these kinds of situations and understand how to redirect or correct as needed — just as they would with any tool they use to manage T1D.

“When a person with diabetes uses a pump, for example, it’s not without the person being required to do something to make the pump work,” she notes. “The same thing is true for D.A.D.s, no matter how well trained.”

The Amazing World of D.A.D.s

Hero, a diabetes alert dog working with a little girl named Sadie, once performed an alert to Sadie’s mother — after Sadie had left to go to school. Sadie’s mother called the school to have Sadie checked, and sure enough, her blood sugar was low.

Another D.A.D., Jedi, detected a low during his overnight watch of his young owner Luke. When Luke didn’t wake to his alert, he jumped on Luke’s mother’s bed and lay on top of her until she woke up. She did and immediately checked Luke’s blood sugar: It was 57 mg/dL. Luke’s mother credits Jedi with saving her son’s life.

Other stories about diabetes alert dogs in action might not make headlines but are just as compelling in showing how service dogs help people with diabetes live normal lives. Hardin recounts a college student who was an avid hiker until health issues landed him in the ER. It was looking doubtful that he would continue living away at school — until he connected with a diabetes alert dog. He stayed on at his college and was soon confidently back on the trail with his D.A.D. by his side.

Another story Hardin likes to share is that of an elderly woman with type 1 diabetes who was living on her own. Her episodes of low blood sugar were alarming to her adult children, and they talked to her about moving to assisted living. Instead, she got a diabetes alert dog. The trained Yorkshire Terrier who came to live with her was the perfect match for her lifestyle and gave her the independence she needed to stay in her home.

D.A.D.s and Kids: A Special Connection

In this age of continuous glucose monitoring (CGM), one might wonder whether diabetes alert dogs are really still that helpful. Hardin believes they are: “Not everyone uses CGM, and even for those who do, it can still feel to the patient like something isn’t right or is missing with the overall management… something else may need to be in place to help this child [or adult].”

Especially for children with type 1 diabetes, a D.A.D.’s presence can give kids — and parents — a greater sense of security. “With a D.A.D. in the equation, it helps these kids feel more confident,” says Hardin. Sometimes it’s a furry assist that can make all the difference.

Thinking About Bringing a D.A.D. Into Your Family?

Hardin recommends the following considerations when searching for a reputable trainer:

  • Look for a trainer who offers complete transparency throughout the entire process, from dog selection and training to what happens if the dog and your child are not a good match or additional training is needed.
  • When trainers offer one-stop fundraising help (whether they’re a for-profit or not-for-profit organization), this is a red flag for a potential conflict of interest.
  • Being placed with a puppy is another red flag, as puppies are too young and unreliable for detection work.
  • A reputable D.A.D. trainer will do what it takes to ensure that the match between a dog and a handler is a successful one.

Disclaimer: The experiences and suggestions recounted in these articles are not intended as medical advice, and they are not necessarily the “typical” experiences of families with a child who has type 1 diabetes. These situations are unique to the families depicted. Families should check with their healthcare professionals regarding the treatment of type 1 diabetes and the frequency of blood glucose monitoring.

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