Popular Science shares a finding that people born without the ability to smell actually inhale and exhale differently than people who can tell what it is they’re smelling:
In other words: Your ability to smell dictates the way you breathe, per the study published October 22 in the journal Nature Communications. Respiratory differences between smellers and non-smellers could have important implications for both physical and mental health, suggest the authors, all scientists within the Olfaction Research Group at the Weizmann Institute of Science in Rehovot.
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The study authors fitted participants with wearable devices that tracked air flow in and out of their noses over 24 hours of normal activity. They followed 31 people with self-reported normal olfaction and 21 participants born without a sense of smell (known as “congenital anosmics”). They found that both smellers and non-smellers had similar breathing rates, but that, while awake, smellers’ respiratory patterns included an average of 240 additional inhalation peaks per hour, compared with non-smellers. These “peaks” represent sniffs, or smaller inhalations on top of a smooth breath in, which give each inhale a jagged shape when charted.
During sleep (when past research has indicated people are less attuned to and responsive to odors) the study scientists noted that the number of inhalation peaks evened out between the two groups. Yet other factors, like the variation in the volume of inhalations, significantly differed between smellers’ and non-smellers’–even while they slept. Altogether, these differences were enough for the researchers to determine someone’s smell-status with 83% accuracy, simply by analyzing their breathing pattern.
In one additional experiment, the study scientists tracked the breathing of 32 normal smellers in a controlled, “odor-free” room. In the scentless environment, they found that the smellers’ breathing became much more similar to that of anosmics, suggesting that respiration pattern is an interplay between sensory ability and environment.
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Acquired anosmia and other types of olfactory dysfunction are associated with many different health conditions, including depression, diabetes, obesity, cognitive decline, and neurodegenerative diseases like Parkinson’s and Alzheimer’s. One analysis found that people aged 57 and older who lose their ability to smell are three times as likely to die over a five-year period than their peers who retain the ability to detect odors.
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You can read more about the olfactory research here, in Nature Communications.