The size of the pupil is at its smallest when we inhale and at its largest when we exhale. A precise camera measured the small changes.
The summary is made by artificial intelligence and checked by a human.
The size of the pupils of the eyes varies with the rhythm of breathing.
The pupil size is at its smallest during inhalation and at its largest during exhalation.
The study investigated the change in pupil size in a hundred test subjects in different experiments.
Previously, it was known that the size of the pupil changes according to the lighting, and it can also change according to emotional states and substances consumed.
The eyes are the mirror of the soul they say. Well, at least the size of the pupils of the eyes changes with each breath we take.
Pupil’s ie the black one the size is at its smallest when we inhale and at its largest when we exhale.
This has been argued before, but the measurements were inaccurate in the experiments.
The discovery was confirmed in experiments by a group of Swedish and Dutch researchers.
Neurotutkija Martin Schaefer from the Karolinska Institute with the help of more than a hundred test subjects and a special camera, found out how the size of the pupil changes when inhalation changes to exhalation.
The change in pupil size is fast because we breathe in and out about 22,000 times a day.
The difference in pupil size is small, but significant when measured.
Test subjects were at rest in one part of the test. In the second phase of the experiment, they focused on a task that required the sense of sight.
It turned out that the size of the human pupil always reaches its minimum when inhalation begins and its maximum size when a person exhales.
This was true for both mouth and nose breathing.
The phenomenon was also measured when the same volunteer subjects just stared at the target and breathed through the nose or mouth.
Over a hundred for a year, vision researchers have known that the pupils react to more than just light.
Pupil sizes change in emotional states, such as when angry or afraid, and also when excited or when a person is under the influence of drugs.
By examining the pupils, doctors can assess an individual’s level of consciousness and mental health. The measurements made now can add to the study of pupils.
Previously, researchers had mistakenly measured that the size of the pupil is at its smallest when a person breathes out.
Some studies suggested the opposite, that the pupils dilate when we inhale. In 2022, a review of the matter concluded that there was no convincing evidence of the phenomenon.
Why does the size of the pupils change even when breathing? It’s not really known.
It has previously been shown that small pupils distinguish fine details. Large pupils help to see faint stimuli better.
Maybe an individual can improve his vision during one breathing cycle according to what he is looking at, thinks Schaefer and his team.
If you wanted to know the phenomenon exactly, it might require animal experiments. With the help of animals, the phenomenon could be measured even more precisely.
Research published by the prepublication service bioRxiv. He also wrote about it online service Science Alert. Now the work is awaiting peer review.