Your nose gets colder when you’re stressed, new thermal images show

Our noses get colder when we’re stressed - and the changes are so significant they can be seen on thermal images, a study has found.

New research from scientists at the University of Surrey shows how blood flow to our faces changes when we’re experiencing stress-related emotion. Using thermal imaging, the team were able to show a “nasal dip” that consistently occurs during stressful situations.

The research involved an experimental stress test where participants were asked to listen to white noise through headphones before being given three minutes to prepare a five minute speech about their "dream job" - all while stared at silently by a panel.

At the same time, thermal imaging was used to track changes to blood flow in the face as the participant’s stress level rose. On each of 29 volunteers, they found their nose dip in temperature by between three and six degrees.

According to researchers, changes in blood flow happen when our arousal system is activated because human brains and bodies evolved to respond to external stressors by being more vigilant.

Because vision is the primary sensory modality of all primates, we are adapted to increase our attention to our visual environment - therefore taking away blood flow from other parts of the face.

This shift causes vasoconstriction around the nose -which in turn creates a marked temperature drop of the nasal tip, compared with when we are calm.

Scientists said the nasal dip can be used as a “real-time, non-invasive unobtrusive, direct biological measure of stress-related emotion”.

Lead researcher, Prof Gillian Forrester is set to demonstrate the dip in front of an audience at the New Scientist Live event in London on 18 October. Her team told the BBC that because it is an evolutionary response present in all primates, it can be used to measure stress levels in apes as well as humans.

"They can't say how they're feeling and they can be quite good at masking how they're feeling," explained Marianne Paisley, a researcher from the University of Sussex. "We've [studied] primates for the last 100 years or so to help us understand ourselves.

"Now we know so much about human mental health, so maybe we can use that and give back to them."