I went digging into that Wikipedia page and found a couple of interesting papers: "The Ultradian Rhythm of Alternating Cerebral Hemispheric Activity" https://d

I went digging into that Wikipedia page and found a couple of interesting papers: "The Ultradian Rhythm of Alternating Cerebral Hemispheric Activity" https://doi.org/10.3109/00207459309000583 https://doi.org/10.3109/00207459309000583 "Effect of uninostril yoga breathing on brain hemodynamics: A functional near-infrared spectroscopy study" https://dx.doi.org/10.4103%2F0973-6131.171711 https://dx.doi.org/10.4103%2F0973-6131.171711 "Selective Unilateral Autonomic Activation: Implications for Psychiatry" https://doi.org/10.1017/S1092852900021428 https://doi.org/10.1017/S1092852900021428 My takeaway: The nervous system is super complicated and has various rhythms. For example the circadian rhythm makes you sleepy at night and alert during the day. There are a bunch of other rhythms that are not yet well studied. The nervous system alternates activity in left and right sides of the body on a rhythm of about 1.5 hours. The nasal cycle is part of this rhythm. One can influence this rhythm by forcing the body to breathe through one nostril. "Klein, Pilon, Prosser, and Shannahoff-Khalsa (1986) assessed cognitive perfor- mance during different phases of the nasal cycle. They observed significant rela- tionships between the pattern of nasal airflow and spatial and verbal performance. Right nostril dominance correlated with enhanced verbal performance, or left brain activity, and left nostril dominance correlated with enhanced spatial performance, again indicating that the hemispheres alternate with the phases of the nasal cycle." "Leconte and Lambert (1988) demonstrated that subjects who undergo a test of immediate memory every 25 min with two modalities (semantic and graphic) present a fluctuation in performance with a periodicity of about 100min. The two modalities were in opposite phase." If breathing can reduce emotional problems for some people, then we could possibly predict this effect by measuring peoples' nasal cycles and hemisphere EEG rhythms. I imagine a typical doctors visit would start out with: 1) filling out the questionnaire, 2) measuring weight, temperature, heart rate, and blood pressure, and then 3) wearing the EEG helmet with nostril sensors for a minute.