Do asthmatics suffer bronchoconstriction during rapid eye movement sleep?

Many patients with asthma are troubled by nocturnal wheeze. The cause of this symptom is unknown, but sleep is an important factor. A study was carried out to determine whether nocturnal bronchoconstriction is related to any specific stage of sleep. Eight asthmatics with nocturnal wheeze and eight control subjects performed forced expiratory manoeuvres immediately after being woken from rapid eye movement (REM) or non-REM sleep, wakings being timed to differentiate temporal effects from those related to the stage of sleep. The control subjects showed no significant temporal bronchoconstriction or bronchoconstriction related to the stage of sleep. All patients showed bronchoconstriction overnight, the mean peak expiratory flow rate falling from 410 (SEM 50) 1/min before sleep to 186 (49)1/min after sleep. After the patients had been woken from REM sleep the forced expiratory volume in one second was on average 300 ml lower (p less than 0.02) and peak expiratory flow rate 45 1/min lower (p less than 0.03) than after they had been woken from non-REM sleep. As wakenings from REM sleep were 21(8) minutes later in the night than those from non-REM sleep multivariate analysis was performed to differentiate temporal effects from those related to the stage of sleep. This showed that the overnight decreases in forced expiratory volume in one second and peak expiratory flow rate were significantly related both to time and to REM sleep. This study suggests that asthmatics may suffer bronchoconstriction during REM sleep.