PEOPLE who claim to be feeling tired all the time may be doing so because of their genes, a new study has found.

Researchers including Edinburgh University scientists have discovered that genes may contribute in a small but significant way to why certain people tire easily or suffer from low energy levels. Being prone to tiredness is partly heritable, according to the new study, which shows that genetics account for eight per cent of differences between people who were asked about their levels of tiredness.

The large-scale study was led by Saskia Hagenaars, a PhD student at the University of Edinburgh’s Centre for Cognitive Ageing and Cognitive Epidemiology and Dr Vincent Deary of Northumbria University.

It is probably the only scientific paper ever published to start with a definition of that good Scots word “wabbit”.

It states: “The Scots word wabbit encompasses both peripheral fatigue, the muscle weakness after a long walk, and central fatigue, the reduced ability to initiate and/or sustain mental and physical activity, such as we might experience while having flu.

“Throughout the paper, we refer mainly to the single English words ‘fatigue’ and/or ‘tiredness’ as the construct captured by the question, but the Scottish vernacular word is a good reminder of the subjective ‘feel’ of fatigue.”

The researchers analysed genetic make-up from 111,749 participants who had reported whether they had felt tired or had low energy in the two weeks before data was collected for the UK Biobank.

They found that the genetic predisposition to tiredness was often present in people genetically prone to a range of mental and physical health conditions, such as smoking, depression and schizophrenia.

A genetic overlap was also identified between low energy levels, and high cholesterol levels and obesity. The researchers say this might indicate a genetic link between tiredness and a vulnerability to physiological stress.