Factors predisposing to exercise-induced late asthmatic responses

Iíkura, Yoji; Inui, Hiroshi; Nagakura, Toshikazu; Lee, Tak H.

doi:10.1016/0091-6749(85)90059-4

Cited by 59 publications

(21 citation statements)

References 21 publications

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“…The results presented are in agreement with those of RUBINSTEIN et al [19] and of BONER and co-workers [23]. In contrast, other investigators have described the existence of a LAR after exercise in asthmatic children [11,13,16]. When comparing the results of our study with those published, a number of methodological points need to be addressed.…”

Section: Discussionsupporting

confidence: 69%

“…For instance, it has not been clarified during which time-period a LAR after exercise might occur. In addition, most authors define the LAR according to a predetermined percentage fall in lung function, either from prechallenge value [12,14,15,[19][20][21], or as compared to lung function measured at an identical timepoint on a control day [13,17,23]. However, these methods are somewhat arbitrary.…”

Section: Discussionmentioning

confidence: 99%

“…Among the 13 studies cited [11][12][13][14][15][16][17][18][19][20][21][22][23], only four used randomized study days [16,[20][21][22]. The choice of "adequate" control days to establish normal diurnal variation in lung function can be considered to be of vital importance [24].…”

Section: Discussionmentioning

confidence: 99%

“…Thereafter, the speed of the treadmill was increased to induce a heart rate of at least 90% of the maximum predicted heart rate for each individual child (maximum heart rate = 210 -age in years). Knowing that the occurrence of a LAR may be dependent upon the severity of the early asthmatic response (EAR) to exercise [13], and knowing that the severity of the EAR to exercise is aggravated when the humidity of the inspired air during exercise is decreased [30], dry air was used to increase the osmotic stress to the airways in order to augment the EAR. This dry air (relative humidity <15%) was inspired from a reservoir bag through a face mask with an inspiratory and expiratory port (Speak Easy II) during running.…”

Section: Exercise Challenge (Ex-days)mentioning

confidence: 99%

“…A number of studies have been published describing the occurrence of a LAR after exercise with prevalence ranging 10-89% [11][12][13][14][15][16][17]. However, nearly as many studies have been unable to document a LAR [18][19][20][21][22][23].…”

mentioning

confidence: 99%

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Occurrence of a late response to exercise in asthmatic children: multiple regression approach using time-matched baseline and histamine control days

Hofstra¹,

Sterk²,

Neijens³

et al. 1996

European Respiratory Journal

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At the present time, there is still controversy concerning the presence of a late asthmatic response (LAR) to exercise challenge in asthma. We have, therefore, investigated the occurrence of a LAR after exercise in asthmatic children visiting an out-patient clinic, using time-matched baseline and histamine control days, and a statistical analysis according to recently published recommendations.After a screening exercise day, 17 children (aged 7-14 yrs) randomly performed, on three subsequent study days, either: a second standardized exercise challenge; or a histamine challenge whilst matching the bronchoconstriction after exercise; or measurement of baseline lung function without any challenge. Measurements of forced expiratory volume in one second (FEV1) were made repeatedly during 8 h. Analysis was performed using multiple regression analysis for each patient, with FEV1 as the dependent, and test day (exercise or control) and clock time as independent variables during the period 2-8 h after exercise. A significant interaction (p<0.05) between test day and clock time was considered to be indicative of a LAR.Fifteen children completed the study. All children showed an early asthmatic reaction to exercise (range 14-62% fall in FEV1). In two children, a significant interaction (p<0.05) was found between test day and clock time. However, the difference in FEV1 between exercise and control days for each clock time did not exceed the 99.6% confidence limits of normal diurnal variation in any of the children.We conclude that, in children with mild-to-moderate asthma, a LAR to exercise does not occur. This suggests that exercise is only a symptomatic trigger of asthma. Whether exercise is capable of inducing inflammation needs to be further investigated.

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