Exercise-induced flow limitation, dynamic hyperinflation and exercise capacity in patients with bronchial asthma

Abstract

It is known that, in stable asthmatics at rest, tidal expiratory flow limitation (EFL) and dynamic hyperinflation (DH) are seldom present. This study investigated whether stable asthmatics develop tidal EFL and DH during exercise with concurrent limitation of maximal exercise work rate (WRmax).A total of 20 asthmatics in a stable condition and aged 32 ¡ 13 yrs (mean ¡ SD) with a forced expiratory volume in one second (FEV1) of 101¡21% of the predicted value were studied. Only three patients exhibited an FEV1 below the normal limits. On a first visit, patients performed a symptom-limited incremental (20 W?min -1 ) bicycle exercise test. On the second visit, the occurrence of EFL (using the negative expiratory pressure technique) and DH (via reduction in inspiratory capacity) were assessed at rest and when cycling at 33, 66 and 90% of their predetermined WRmax. FEV1 was measured to detect exercise-induced asthma, 5 and 15 min after stopping exercise at 90% WRmax.Only one patient showed EFL at rest, whereas 13 showed EFL and DH during exercise. In these 13 asthmatics, exercise capacity was significantly reduced (WRmax 75¡9% pred) compared to the seven non-EFL patients (WRmax 95¡13% pred). Moreover, a significant correlation of WRmax (% pred) to the change in inspiratory capacity (percentage of resting value) from rest to 90% WRmax was found. Tidal EFL during exercise was not associated with exercise-induced asthma, which was detected in only three patients.In conclusion, tidal expiratory flow limitation and dynamic hyperinflation during exercise are common in stable asthmatics with normal spirometric results and without exercise-induced asthma, and may contribute to reduction in exercise capacity.

Flow limitation and dynamic hyperinflation: key concepts in modern respiratory physiology

“…Indeed, 48% of COPD patients were EFL as compared with 15% of stable asthmatics at comparable FEV1 values [22,25,[42][43][44]. In contrast with COPD patients, most asthmatics do not exhibit EFL during resting breathing seated and/or supine [28,[42][43][44][45][46]. This discrepancy between asthma and COPD may reflect a lower elastic recoil in the latter condition.…”

“…2). This method does not require FVC manoeuvres, collaboration on the part of the patient or use of a body plethysmograph, and can be used during spontaneously breathing subjects in any body position [27], during exercise [24,28,29] and in an ICU setting [7,8,23,[30][31][32]. With this method, the volume and time history of the control and test expiration are the same.…”

“…different body postures [27], rest and exercise [24,28,29], in spontaneously breathing and mechanically ventilated subjects [7,8,23,[30][31][32], paediatric [26,38], neurological [39] and geriatric settings [40,41].…”

Physiological techniques for detecting expiratory flow limitation during tidal breathing

“…This method does not require performance of FVC manoeuvres, collaboration on the part of the patient or use of a body-box. It can be used during spontaneous breathing in any body position [45], during exercise [18,46,47], and in ICU settings [21][22][23][24][25][26]. With this technique the volume and time history of the control and test expiration are axiomatically the same.…”

The Impact of Exercise-Induced Bronchoconstriction on Athletic Performance: A Systematic Review

“…In recreationally active asthmatic individuals, Haverkamp et al [32] reported an increase in average pulmonary resistance for the entire exercise duration and for the majority of subjects, expiratory flow limitation was evident. Furthermore, others have shown that EELV increases in exercising asthmatics [33].…”