Review
Asthma, classical conditioning, and the autonomic nervous system – a hypothesis for why children wheeze
Gary James Connett http://orcid.org/0000-0003-1310-3239
Archives of Disease in Children
https://adc.bmj.com/content/early/2023/08/30/archdischild-2023-325441

Paediatric asthma is an increasing global health-care problem for which current treatments are not always effective.
This review explores how abnormal triggering of the autonomic diving reflex might be important in explaining research findings & the real-world experience of asthma.
It hypothesises:
the way in which stress during pregnancy is ass.x childhood asthma could be through effects on the developing nervous system.
This results in increased parasympathetic responsiveness, specifically excessive triggering of the diving reflex, in response to wetting & cooling of the face & nose, as occurs with upper airway infections & allergic rhinitis..
In aquatic mammals, the reflex importantly includes the contraction of airway smooth muscle, to minimise lung volume, and prevent nitrogen narcosis from diving at depth.
Mis-firing of this reflex in humans could result in the pathological airway narrowing that occurs in asthma.
The diving reflex, and possibly also smooth muscle, is a vestigial remnant of our aquatic past.
The hypothesis further suggests:
classically conditioned reflex responses to neutral cues and contexts that were present at the same time as the stimuli that initially caused symptoms, become of themselves ongoing triggers of recurrent wheeze.
Symptoms occurring in this way (irrespective of the presence of allergens & ongoing airway sensitisation) explain
- why allergen avoidance is poorly effective in alleviating wheeze,
- why asthma is made worse by stress.
Interventions to suppress the diving reflex, and to prevent reflex conditioned wheezing could result in more effective asthma management.

The aquatic ape theory and some common diseases
M Verhaegen 1987 doi 10.1016/0306-9877(87)90076-4

The Aquatic Ape Theory claims that human ancestors once lived in a semi-aquatic habitat.
Some human diseases might be explained by our aquatic past, incl.
- hyperventilation,
- periodic breathing,
- laryngo- & bronchospasm,(incl.asthma --mv)
- vasomotor rhinopathy,
- seborrhea, dandruff,
- male pattern alopecia,(="disease"?? :-) --mv)
- rhinophyma,
- osteoarthritis,
- inguinal hernias,
- varicose veins,
- common obesity,
- myopia,
- ear-wax.
(& probably many others?
I suffered from severe (mostly allergic) asthma as a child.
These problems are minimal today, but now I suffer from diverse old-age problems... :-( --mv)