Long used by police to test motorists for intoxication and by doctors screening for a variety of health problems, researchers say breath devices may now measure stress.

Investigators at Loughborough University and Imperial College London took breath samples from 22 young adults in two setting, relaxed and stressed, finding six markers indicating the presence of stress in the body. Two compounds in breath (2-methy, pentadecane and indole) increased following inducement of stress in the experiments, as reported by The Telegraph.

They also found four compounds that decreased with stress, which were probably related to changing breathing patterns, researchers reported in the Journal of Breath Research, adding that more studies should be conducted to confirm the results.

Aside from alcohol intoxication, breath test devices manufactured by Menssana Research, Inc., of Newark, NJ, can detect the presence of diseases such as lung and breast cancers, pulmonary tuberculosis and other diseases. These devices are currently undergoing Phase II and Phase III clinical trials. In addition, a hydrogen breath test has become commonplace for clinical diagnosis of dietary disabilities such as fructose intolerance, fructose malabsorption, lactose intolerance and lactulose intolerance. A urea breath test may detect the presence of Helicobacter pylori in peptic ulcer disease. The detection of nitric oxide in breath, likewise, signals airway inflammation likely associated with asthma.

Lead investigator Paul Thomas touted the benefits of such testing. "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 careers, such as those suffering from Alzheimer's."

However, researchers say they're still unsure how to best isolate external confounding factors such as diet, environment and exercise that affect patient breath samples.

"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," says Thomas. "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.

Thomas said investigators would consider in future studies the challenge of placing subjects under stress while maintaining high ethical standards for human experimentation.