"The bugs can't survive at higher temperatures.
"When your immune system is under attack the preoptic nucleus increases temperature to kill off the bugs. But men have more temperature receptors because that area of the brain is bigger in men than women.
"So men run a higher temperature and feel rougher - and if they complain they feel rough then maybe they're right."
Research published in 2009 which also supported the existence of man flu was criticised as inconclusive as it related to genetically engineered mice rather than humans. But Dr Ellison's study was based on research carried out on human brains.
"It is part of the whole argument about the differences between men and women and how their behaviour can be influenced by differences in their brains," she added.
Commenting on the fact that her findings could be seen as controversial, Dr Ellison said: "I'm just throwing it out there. The debate will rage on and quite rightly so. The trouble with man flu has always been that there is not much hard evidence that the feelings are worse in males than in females. This is just a possible cause."
- DAILY MAIL