– EN Fitness & Wellbeing – Brown-eyed girls are more likely to feel the negative effects associated with bad weather, researchers claim.
Academics at the University of South Wales believe that dark eyes block more sunlight during shorter days of the year, which affects the production of serotonin – a known mood booster – and can, therefore, contribute to symptoms of seasonal affective disorder (SAD).
This type of depression, which is more apparent in the winter months, has the potential to hinder day-to-day activities in the most severe of cases.
“If you are a woman with brown eyes, based on our study, you are more than twice as likely to suffer from SAD as a blue-eyed man,” lead author Professor Lance Workman told MailOnline reporters. “We suggest that blue eyes may have developed in European people as a genetic mutation 10,000 years ago to help protect them from the energy and depressive effects of living so far from the Equator during the winter months.”
Results of the study were presented at the British Psychological Society conference, which examined 175 people from both Cyprus and the U.K.
In addition, over 2,000 British people were surveyed, with results suggesting that women were 40 per cent more likely to develop SAD than men.
Again, the experts believed this could be another example of evolution and suggested that this figure could be evidence that women conserve more energy in the winter months to better care for their children.
Though the exact cause of SAD isn’t fully understood, Britain’s National Health Service (NHS) believe a lack of sunlight may stop the hypothalamus in the brain from working properly.
As well as influencing the amount of serotonin produced, this could also cause increased production of melatonin (the hormone which makes us feel sleepy) and disrupt the body’s circadian rhythm, also known as the body clock.
The condition can be treated by altering lifestyle, light or talking therapy, as well as antidepressant medication.