the University of Cambridge. The finding, published today in the journal Diabetes Care, could explain why some dogs can be trained to spot the warning signs in patients.

The researchers found that levels of the chemical isoprene rose significantly at hypoglycaemia – in some cases almost doubling. They believe that dogs may be sensitive to the presence of isoprene, and suggest that it may be possible to develop new detectors that can identify elevated levels of isoprene in patients at risk.