Loss of sense of smell may affect breathing patterns and our mental health, new study suggests
Oct. 22, 2024, 9:57 PM GMT+5
Anosmia has been previously linked to a wide variety of mental and physical health challenges, ranging from dulled emotions and depression to a shortened lifespan.
Not having — or losing — your sense of smell may be linked to changes in breathing that could lead to depression, social isolation or other mental and physical health problems, a new study suggests. It's more evidence of how important this often neglected olfactory sense is.
A new analysis of breathing data from 52 volunteers over a 24-hour period revealed that people with a normal sense of smell had little spikes, or “sniffs,” during each breath that were not seen in those with no sense of smell, according to the report published in Nature Communications on Tuesday.
People can be born with no sense of smell, a condition called anosmia, or they can acquire it, as has been the case with many who had a Covid infection.
The volunteers in the study without the ability to detect odors were all born with the condition.
Nearly 1 in 4 people have anosmia, according to National Institutes of Health estimates. Experts say that number is likely an undercount.
A 2023 report determined that more than 60% of people diagnosed with Covid developed anosmia. About 72% of those completely regained their sense of smell, while about a quarter partially got their sense of smell back. Nearly 4% of people after Covid infection didn't recover their ability to smell.
Even for those in the 4%, there may still be hope, since some get their sense of smell back as late as three years after their infection, experts say. There are treatments that may help, such as smell training or a procedure known as a stellate ganglion block.
The main takeaway from the study is better insight into some of the mental issues that some Covid patients who have lost their sense of smell experience, said the study’s lead author, Lior Gorodisky, a Ph.D. candidate in the brain sciences department at the Weizmann Institute of Science in Rehovot, Israel.
The differences in breathing between those who can smell and those who can’t are pretty significant. “We are now also able to identify lifelong anosmia just based on the respiratory pattern,” Gorodisky said in an email.
The little inhalations during a breath, known as the “sniff response,” are something that most of us experience unconsciously every day, Gorodisky said. Those little sniffs tell our brains about good and bad smells. “When you go to a bakery or a flower field, once your brain has sensed the good smell of a pastry or a flower, you immediately take a deeper breath,” Gorodisky said.
To determine whether having anosmia might affect respiration, the researchers supplied the 52 volunteers with nasal devices that would monitor breathing as they went about their days.
Previous research has linked anosmia to a wide variety of negative outcomes, ranging from dulled emotions and depression to a shortened lifespan, the authors noted.