7/25/2023 0 Comments Nocturnal asthma emedicine![]() (increasing in airway resistance).5 This worsening of airway function overnight is not caused by a single process. Sleep itself produces a further worsening of lung function 3 there was a progressive increase in airway resistance from midnight until 6 am, independent of sleep. However, the nocturnal asthma group had a much greater increase in bronchial reactivity during the night.ĭoes sleep itself alter the asthma rate? As shown in Fig. 49.)Įven the asthma control population from 4 pm to 4 am had a worsening of bronchial reactivity. Epi, epinephrine Sa02, oxygen saturation. 4 The complex interactions between various factors leading to the nocturnal worsening of asthma. ![]() 3 Airway resistance (Rla) in six asthmatic patients progressively increases from midnight (0000 h) to 6 am (0600 h) independent of sleep (□), but sleep itself has a profound effect on increased airway resistance ( 2 Bronchial hyperresponsiveness increases by approximately two-fold from 4 pm (1600 h) to 4 am (0400 h) in a group of asthmatic subjects who have small alterations in their FEV] (control group) and by eight-fold in the nocturnal asthma group. For both groups, the peak lung function occurs at approximately 4 pm (1 600 h) and nadir lung function at 4 am (0400 h). 1 Peak expiratory flow rate (PEFR) and forced expiratory volume in 1 second (FEVJ are schematically shown for normal subjects and asthmatic patients. The asthmatic population, however, can have much more dramatic overnight decrements in lung function than the normal population.īronchial hyperresponsiveness has been evaluated between 4 pm and 4 am in two asthmatic groups.4 One group was an asthmatic control population, and the other had nocturnal asthma. The asthmatic patients, however, start with a lower lung function level, but independent of medications still have the highest peak flow rates at approximately 4 pm and the lowest at approximately 4 am. The best lung function occurs around 4 pm and the worst lung function approximately 4 am with about an 8% change in the normal population. E-mail: Received 25 November 1 996.įigure 1 schematically shows the arcadian rhythm change in lung function in both normal subjects and asthmatic patients.3 Even in normal subjects there is a day-to-day change in lung function. Dr Turner-Warwick demonstrated in a very large population study of almost 8000 asthmatic outpatients that 39% had symptoms of asthma every night, 64% at least three nights per week and 74% at least one night per week.2 Thus, the asthmatic patient who appears stable during the daytime hours may in fact have marked worsening of asthma at night.Ĭorrespondence: Dr Richard J Martin, National Jewish Center for Immunology and Respiratory Medicine, 1400 Jackson Street, Room J116, Denver, Colorado 80206, USA. Dr John Floyer describing his own asthma in 1698 wrote, 'I have observed the fit always to happen after sleep in the night, when the nerves are filled with windy spirits and the heat of the bed has rarefied the spirits and humours.'1 Dr Floyer is giving us an insight into what our asthma patients experience at night. Key words: chronobiology, chronotherapy, nocturnal asthma, pathophysiology.Īsthma is a disease particularly suited to a discussion of chronobiology and chronotherapy because the pattern of the disease often changes from the waking to the sleeping state. This article reviews the nocturnal worsening of asthma. Asthma is one of the disease entities that has been studied in detail in regard to both time related alterations in pathophysiology and treatment. However, important knowledge has been gained so as to better understand both the pathophysiology of diseases and the corresponding therapeutic interventions. The field of chronobiology and chronotherapy in medicine is in its relative infancy. Pulmonary Division, National Jewish Center for Immunology and Respiratory Medicine and University of Colorado Health Sciences Center, Denver, Colorado, USA Nocturnal asthma: Understanding chronobiology and chronotherapy
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