Asthma Bronchiale and Exercise-Induced Bronchoconstriction

Abstract

Exercising regularly has a wide range of beneficial health effects; in particular, it has been well documented to help in the management of chronic illnesses including asthma. However, in some individuals, exertion can also trigger an exacerbation of asthmatic episodes and subsequent acute attacks of breathlessness, coughing, tightness of the chest and wheezing. This physiological process is called exercise-induced bronchoconstriction (EIB) whereby post-exercise forced expiratory volume in 1 s is reduced by 10-15% from baseline. While EIB is highly prevalent in asthmatics and presents with similar respiratory symptoms, asthma and EIB are not mutually exclusive. The aim of this review is to present a broad overview of both conditions in order to enhance the understanding of the similarities and differences distinguishing them as two separate entities. The pathophysiology and mechanisms underlying asthma are well described with research now focussing on defining phenotypes for targeted management strategies. Conversely, the mechanistic understanding of EIB remains largely under-described. Diagnostic pathways for both are established and similar, as are pharmacologic and non-pharmacologic treatments and management approaches, which have enhanced success with early detection. Given the potential for exacerbation of asthma, exercise avoidance is common but counterproductive as current evidence indicates that it is well tolerated and improves quality of life. Literature supporting the benefit of exercise for EIB sufferers is at present favourable, yet extremely limited; therefore, future research should be directed in this area as well as towards further developing the understanding of the pathophysiology and mechanisms underpinning both EIB and asthma.

Ovalbumin induces natural killer cells to secrete Th2 cytokines IL‑5 and IL‑13 in a mouse model of asthma

“…Allergic asthma is a chronic airway disorder characterized by symptoms that include wheeze, cough, shortness of breath and chest tightness (1,2). An estimated 300,000,000 individuals worldwide suffer from asthma which imposes a substantial economic burden on individuals and society (3).…”

The Aftermath of Bronchoconstriction

“…As a common feature of asthma that causes symptoms, constriction of the airway occurs due to the tightening of surrounding smooth muscle [24]. This may arise in response to a variety of causes including exercise, environmental exposure, and can be worsened by both recurrent infection and, in sensitized patients, allergen exposure [24][25][26][27]. Asthmatic bronchoconstriction may lead to consequent coughing, wheezing, and shortness of breath [20].…”

Pathophysiology of bronchoconstriction

“…The resulting clinical symptoms include wheezing, chest tightness, shortness of breath, and dyspnea and are features of asthma, chronic bronchitis, chronic obstructive pulmonary disease (COPD) [9,10,11,12,13,14,15]. In severe cases the airway narrowing can be fatal [16].…”