Washington: Asthmatics who believe that an odour is potentially harmful have increased airway inflammation for at least 24 hours following exposure, a new study has found. The findings highlight the role that expectations can play in health-related outcomes, said researchers from the Monell Chemical Senses Centre in the US.
“Asthmatics often are anxious about scents and fragrances. When we expect that an odour is harmful, our bodies react as if that odour is indeed harmful,” said study lead author Cristina Jaen, a Monell physiologist.
The airways of asthmatics are sensitive to ‘triggers’ that inflame and constrict the airways, making it difficult to breathe.
In the study, 17 individuals characterised as moderate asthmatics were exposed to the odour phenylethyl alcohol (PEA) for 15 minutes. Often described as rose-smell-ing, PEA is regarded as a ‘pure’ odourant with no associated physiological irritant qualities. Eight subjects were told that the odour had potential therapeutic properties, while nine were told that it potentially could cause mild respiratory problems. Data showed that the subjects’ beliefs about the odour, influenced both their psychological and physiological responses to odour exposure.
