Breath analysis could measure stress
6 March 2013
A study by Loughborough University and Imperial College London,
has identified six chemical markers in the breath that could be
candidates for use as indicators of stress.
The researchers hope that the findings could lead to a quick,
simple and non-invasive test for measuring stress. However, they
caution that with just 22 subjects, more studies are needed to
include more people, over a wider range of ages and in more “normal”
settings, before any concrete conclusions can be made.
Lead-author of the study Professor Paul Thomas, said: “If we can
measure stress objectively in a non-invasive way, then it may
benefit patients and vulnerable people in long-term care who find it
difficult to disclose stress responses to their carers, such as
those suffering from Alzheimer’s.”
The study, published in the Journal of Breath Research, involved
22 young adults (10 male and 12 female) who each took part in two
sessions: in the first, they were asked to sit comfortably and
listen to non-stressful music; in the second, they were asked to
perform a common mental arithmetic test that has been designed to
A breath test was taken before and after each session, whilst
heart-rates and blood pressures were recorded throughout. The breath
samples were examined using a technique known as gas
chromatography-mass spectrometry, and then statistically analysed
and compared to a library of compounds.
Two compounds in the breath, 2-methyl, pentadecane and indole,
increased following the stress exercise which, if confirmed, the
researchers believe could form the basis of a rapid test. A further
four compounds were shown to decrease with stress, which could be
due to changes in breathing patterns.
“What is clear from this study is that we were not able to
discount stress. It seems sensible and prudent to test this work
with more people over a range of ages in more normal settings,"
Professor Thomas continued.
“We will need to think carefully about experimental design in
order to explore this potential relationship further as there are
ethical issues to consider when deliberately placing volunteers
under stress. Any follow up study would need to be led by experts in
Breath profiling has become an attractive diagnostic method for
clinicians, and recently researchers have found biomarkers
associated with tuberculosis, multiple cancers, pulmonary disease
and asthma. It is still unclear how to best manage external factors,
such as diet, environment and exercise, which can affect a person’s
“It is possible that stress markers in the breath could mask or
confound other key compounds that are used to diagnose a certain
disease or condition, so it is important that these are accounted
for,” said Professor Thomas.
The researcher’s initial assumptions are that stressed people
breathe faster and have increased pulse rates and an elevated
blood-pressure, which is likely to change their breath profile. They
emphasise, however, that it is too soon to postulate the biological
origins and the roles of the compounds as part of a stress-sensitive
Turner MA, et al. The effect of a paced auditory serial addition
test (PASAT) intervention on the profile of volatile organic
compounds in human breath: a pilot study. Journal of Breath
Research, 2013, Volume 7 Number 1. doi:10.1088/1752-7155/7/1/017102.
The paper can be downloaded from: