Why are asthma attacks likely to occur in the middle of the night and/or early morning? ① The decrease in PEFR (peak flow rate value) at night is closely related to the decrease in blood catecholamine levels; ② Plasma epinephrine and adenosine monophosphate are lowest in the early morning hours; ③ Plasma histamine levels are highest in the early morning hours; ④ Plasma hydrocortisone is lowest in the middle of the night; ⑤ Nocturnal attacks may be related to dust mites. Risk factors and causative factors of bronchial asthma 1. atopy: eczema, allergic rhinitis, family history of allergic diseases 2. Gender (more boys than girls). 3.Causal factors: ① indoor and outdoor allergens; ② drugs and food; ③ respiratory infections; ④ smoking; ⑤ exercise and hyperventilation; ⑥ emotional agitation; ⑦ other: rhinitis, sinusitis, nasal polyps, gastroesophageal reflux, etc. 4. Race: There is little difference.