Breathing is something you do all day long, without even thinking about it. And that's exactly why you might be doing it wrong. Research shows that the way you breathe may not only affect the amount of oxygen you take it, it may also change how you think and feel.
So which is it? Do you breathe through your nose or through your mouth? Some health experts recommend that people breathe in through their noses and out through their mouths. Others say that people should just focus on breathing easily, regardless of their mouth/nose preference. But mouth breathing has also been associated with bad breath, snoring, sleep apnea, high blood pressure and misaligned teeth, according to the Academy of General Dentistry.
New research shows that breathing through your nose may improve your memory.
Breathing through your nose may affect how memories are reinforced and stabilized in our brains, according to researchers from the Karolinska Institutet in Sweden. During the study, participants smelled a set of 12 different scents and then were asked either to breathe through their nose or mouth for an hour afterwards. Then, they were presented with the original set of smells and a new set. Those who smelled with their nose remembered the scents better.
"The idea that breathing affects our behaviour is actually not new," wrote Artin Arshamian, researcher at the Department of Clinical Neuroscience, Karolinska Institutet. "In fact, the knowledge has been around for thousands of years in such areas as meditation. But no one has managed to prove scientifically what actually goes on in the brain. We now have tools that can reveal new clinical knowledge."
Breathing and brain activity
Previous research also shows how nose breathing affects brain activity by helping you think more clearly and react more quickly to stress.
In 2017, a team from Northwestern University used electroencephalography (EEG) data from seven epilepsy patients to distinguish the differences in brain activity that occurred when patients breathed through their noses or through their mouths. They also compared inhalations with exhalations. With electrodes that had been implanted in their brains during surgery to control their seizures, researchers were able to note how the electrical activity changed in the brain in sync with breathing patterns.
The team found three areas of the brain where activity correlated with breathing — the piriform cortex, which processes smells; the hippocampus, which controls memory; and the amygdala, which controls fear and pleasure responses. These areas showed major changes in brain activity when volunteers inhaled — but only when they inhaled through their noses. Mouth breathing did not stimulate the brain in any area.
Researchers then looked at the brain activity in the amygdala of dozens of healthy volunteers who did not have epilepsy. This is the area of the brain that controls emotional responses and can trigger the flight or fight response. The participants were asked to undergo memory tests that involved interpreting facial expressions. The team found that when volunteers breathed through their noses, they were better at remembering and identifying faces that displayed fear. They also did better in subsequent memory tests, but again only when breathing through their noses. The researchers findings were published in the Journal of Neuroscience.
Dr. Eugene Gamble, an oral periodontal surgeon and fellow with the Royal College of Surgeons in Ireland, who was not involved in the study, tells MNN that it makes sense that breathing through the nose would stimulate the brain. "I do think it's more than plausible that nasal breathing has an affect on memory as we all have instances where we've smelled a certain fragrance or odor and then been transported almost instantly to a childhood memory," Gamble says.
Researchers pointed out that though the correlations they found were significant, they were still just associations and not necessarily examples of a cause and effect. But they did theorize that a connection between breathing and brain activity might be helpful for people experiencing a flight or fight situation. For most people, panic causes increased breathing and when that increased breathing also stimulates memory and thinking skills, it can help you survive an emergency. But that level of brain stimulation is apparently only happening for nose breathers. Mouth breathers are out of luck.
Changing the way you breathe
So should mouth breathers change their breathing habits? In addition to the potential benefits mentioned above, Gamble notes that nasal breathing filters bacteria, fungi and dust from the air while warming it before it enters the body and it is more efficient because "there is slower exhalation which gives greater oxygen transference per breath."
If you're happy with the way you breathe and you aren't experiencing any health problems, it's probably worth leaving well enough alone. But if you think it might be time for a change, focus on breathing through your nose for a few minutes each day until it becomes a habit. Who knows, it might help you survive an emergency — or at the very least, it might make you less likely to get a cold.
Editor's note: This article has been updated since it was originally published in January 2017.