Λεξικό .. Biorhythms in allergy

It is recognized the circadian periodicity of rhinitis symptoms-sneezing, runny rose and blocked nose. They all have a peak incidence at around 8 a.m. Another example is the peak incidence of asthma attacks which occur between 4 a.m. and 7 a.m. Even in normal individuals airway caliber varies in a circadian pattern falling to a nadir at around 4 a.m. Evidence for an increase in vagal tone at night is supplied by the specific cardiovascular measure of the sinus arrhythmia gap.

This increased cholinergic stimulation contributes to nocturnal bronchoconstriction. A fall in adrenaline, mirroring the fall in airway caliber, may also be causal through increasing mast-cell mediator release and decreasing cholinergic tone. The midnight fall of cortisol may be due to the fall in steroid effects at around 4 a.m., again leading to mediator release. Barnes, P.: Circadian rhythms in allergy.

References

Symposium 9. In XIVth Congress of EAACI, Berlin, Sept. 18, 1989.