Purpose: Intensive exercise modifies airway inflammation and infection susceptibility. We aimed to determine the effect of exercise on pro- and anti-inflammatory cytokine (TNF-α, IL-1ra, IL-10) and innate immunity protein (HSPA1, sCD14) levels in exhaled breath condensate (EBC) and nasal secretions of competitive athletes, non-exercising asthmatics and healthy controls (HC).
Material and methods: The study group consisted of 15 competitive athletes (five speed skaters and ten swimmers) aged 15-25. The control groups comprised 10 mild-to-moderate asthmatics (AC) and seven HC. Athletes were assessed in- and off-training while asthmatics and controls at one time point. Nasal lavages and EBC were collected before and after a treadmill exercise challenge. Protein levels were assessed using ELISA.
Results: TNF-α levels in EBC were significantly higher in athletes than HC, but similar to asthmatic patients. In contrast, IL-1ra EBC concentrations were significantly lower in athletes than in HC, but again similar to asthmatics. Significant positive correlations were seen between baseline concentrations of TNF-α in EBC and fall in FEV1 following exercise challenge in athletes during training period (R=0.74, p<0.01) and in asthmatics (R=0.64, p<0.05). In nasal secretions, baseline IL-1ra levels were significantly higher in athletes and asthmatics than in HC. Exercise caused a slight, yet significant, increase in EBC HSPA1 in athletes (p=0.02). The exercise challenge did not considerably influence TNF-α, IL-1ra, HSPA1 and sCD14 in EBC or nasal secretions.
Conclusions: Dysregulation of the TNF-α/IL-1ra balance in EBC and nasal secretions from athletes may reflect the presence of airway inflammation induced by repeated strenuous exercise.
Keywords: Airway inflammation; Asthma; Competitive athletes; Exercise; Innate immunity.
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