This review presents state-of-the-art knowledge and identifies knowledge gaps for future research in the area of exercise-associated modifications of infection susceptibility. Regular moderate-intensity exercise is believed to have beneficial effects on immune health through lowering inflammation intensity and reducing susceptibility to respiratory infections. Infection-promoting consequences are attributed to strenuous exercise as performed by professional athletes. In about half of the athletes presenting respiratory symptoms, no causative pathogen can be identified. Acute bouts of exercise enhance release of proinflammatory mediators thus probably leading to appearance of infection-like respiratory symptoms. Studies assessing influence of regularly repeated exercise on immune response and systemic inflammation are far less numerous than those regarding acute exercise effects. This identifies another knowledge gap requiring further assessment both in recreational and in professional athletes Additionally, ambient and environmental conditions modify systemic inflammatory response and infection susceptibility in particular in outdoor athletes. Both acute and chronic regular exercise influence humoral and cellular immune response mechanisms resulting in decreased specific and non-specific response in competitive athletes. Most promising areas of further research in exercise immunology include: detailed immunological characterization of infection-prone and infection-resistant athletes; efficacy of nutritional and pharmaceutical interventions as countermeasures to infections’ symptoms; and influence of various exercise loads on susceptibility to infections with respiratory viruses, including SARS-CoV-2. Establishing uniform definition of “elite athlete’ shall hopefully allow for comparable and straightforward interpretation of data coming from different studies and settings.

Concerns have been raised regarding the potential negative effects on human health of water disinfectants used in swimming-pools. Among the disinfection options, the approaches using chlorine-based products have been typically preferred. Chlorine readily reacts with natural organic matter that are introduced in the water mainly through the bathers, leading to the formation of potentially harmful chlorination by-products (CBPs). The formation of CBPs is of particular concern since they have been epidemiologically associated with the development of various clinical manifestations. The higher the concentration of these volatile CBPs in the water, the higher their concentration in the air above the pool, and different routes of exposure to chemicals in swimming-pools (water ingestion, skin absorption and inhalation) contribute to the individual exposome. CBPs may affect the respiratory and skin health of those who stay indoor for long periods, such as swimming instructors, pool staff, and competitive swimmers. Whether those who use chlorinated-pools as customers, particularly children, may also be affected has been a matter of debate. In this article, the EAACI Joint Task Force of the Working Group of Allergy, Asthma & Sports and the Interest Groupf of Environmental & Occupational Allergy discusses the current evidence regarding the health effects of both acute and chronic exposures in different populations (work-related exposures, intensive sports and recreational attendance) and identify the main recommendations and unmet needs for research in this area.

Background: Anaphylaxis is increasing at pediatric age; however, its characterization is hampered by underdiagnosis and underreporting. The aim of this study was to identify the causes of anaphylaxis in children and adolescents in Portugal, thus contributing to a better knowledge of its etiology, clinical manifestations and management. Methods: During a 10-year period a nationwide notification system for anaphylaxis was implemented, with voluntary reporting by allergists. Data on 533 patients under 18 years of age with anaphylaxis were included. Results: Mean age was 8.5±4.9 years, 61% were male; 45% had asthma. Mean age at the first anaphylaxis episode was 5.3±4.7 years (ranging from 1 month to 17 years of age), 63% at preschool age. Most reactions occurred at home (57%). Food-induced anaphylaxis was the leading cause (77%). The main culprit foods were cow’s milk (32%), tree nuts (16%), shellfish (13%), egg (12%), fresh fruits (11%), fish (8%) and peanut (8%). Other causes included drugs (11%), insect-sting (5%), cold-induced anaphylaxis (4%), exercise-induced (2%), latex (1%) and idiopathic anaphylaxis (1%). Most patients (83%) were admitted to the emergency department; only 46% received adrenaline treatment. Recurrence of anaphylaxis occurred in 41% of the patients (3 or more episodes in 21%). An adrenaline autoinjector was used in 9% of the patients. Conclusions: In the Portuguese pediatric population, food is the leading cause of anaphylaxis. Undertreatment with adrenaline and high recurrence of anaphylaxis highlight the need to improve both the diagnosis and the therapeutic management of this life-threatening entity.