Scientists may have figured out how dogs are able to detect low blood sugar in their owners.

According to the authors of the study published in Diabetes Care, the findings could lead to the development of new medical sensors to detect hypoglycaemia.

The team of researchers from the Wellcome Trust-MRC Institute of Metabolic Science and the University of Cambridge recruited eight women with type 1 diabetes and gradually lowered their blood sugar levels under controlled conditions.

They then took exhaled breath samples and found that the chemical isoprene rose significantly at hypoglycemia compared with non-hypoglycemia. There was no significant rise in other volatile organic compounds such as acetone, ethanol and propane.

Although it was unclear how hypoglycemia could increase isoprene, the researchers suggest it may be a by-product of cholesterol biosynthesis. The authors stress that their findings do not definitively prove that dogs are smelling isoprene when they detect diabetes.