Mucosal immunity and upper respiratory tract symptoms in recreational endurance runners

• Published in: Applied physiology, nutrition, and metabolism Vol. 41; no. 1; pp. 96 - 102
• Main Authors: Ihalainen, Johanna K, Schumann, Moritz, Häkkinen, Keijo, Mero, Antti A
• Format: Journal Article
• Language: English
• Published: Canada NRC Research Press 01.01.2016; Canadian Science Publishing NRC Research Press
• Subjects: Adult; alpha-amylase; antimicrobial proteins; Athletes; Biomarkers - metabolism; Body fluids; Body Mass Index; Body Weight; Diagnosis; Disease Resistance - immunology; Endurance sports; endurance training; entraînement en endurance; enzyme activity; exercise; exercise immunology; health; Health aspects; Humans; Immunity, Mucosal; immunoglobulin A; Immunoglobulin A - analysis; immunoglobulin G; immunoglobulin M; Immunoglobulin M - analysis; Immunological research; immunologie de l’exercice; lysozyme; Male; males; men; metabolism; mucosal immunity; nutrition; Physical Endurance - immunology; Physiological aspects; Proteins; protéines antimicrobiennes; Respiratory diseases; respiratory system; Respiratory System - immunology; Respiratory Tract Diseases - epidemiology; Respiratory tract infections; Retrospective Studies; Runners (Sports); Running; Running - physiology; saliva; Saliva - chemistry; Saliva - immunology; Salivary alpha-Amylases - metabolism; salive; santé; Surveys and Questionnaires; symptômes des voies respiratoires supérieures; Training; upper respiratory tract symptoms; Wisconsin; Wisconsin; exercise immunology; endurance training; health; entraînement en endurance; immunologie de l’exercice; saliva; protéines antimicrobiennes; performance; symptômes des voies respiratoires supérieures; antimicrobial proteins; santé; upper respiratory tract symptoms; salive
• ISSN: 1715-5312; 1715-5320; 1715-5320
• DOI: 10.1139/apnm-2015-0242

The present study investigated the effects of a 12-week endurance-training intervention on salivary proteins and upper respiratory tract symptoms (URS) in 25 young men. Saliva samples of 25 recreational male endurance runners (age 34.6 years, body mass index = 23.8 kg·m −2 , peak aerobic capacity = 47.2 mL·kg −1 ·min −1 ) were collected before (PRE) and after (POST) the training intervention, in a fasting state, as well as both before and after a maximal incremental treadmill run. The training consisted of both continuous and interval training sessions, 4–6 times per week based on the polarized training approach. Participants filled in Wisconsin Upper Respiratory Symptom Survey-21 and were retrospectively divided into 2 groups according to whether they reported URS (URS group, n = 13) or not (HEALTHY group, n = 12). Basal salivary immunoglobulin A (sa-sIgA) levels were significantly higher (+70%, p < 0.05) in the HEALTHY group both at PRE and POST whereas no significant differences were observed in salivary immunoglobulin M, salivary immunoglobulin G, lysozyme, or salivary α-amylase activity (sAA). Sa-sIgA concentration at PRE significantly correlated with the number of sick-days (R = –0.755, p < 0.001) in all subjects. The incremental treadmill run acutely increased sAA significantly (p < 0.05) at PRE (200%) and POST (166%) in the HEALTHY group but not in the URS group. This study demonstrated that subjects, who experienced URS during the 12 weeks of progressive endurance training intervention, had significantly lower basal sa-sIgA levels both before and after the experimental endurance training period. In addition to sa-sIgA, acute sAA response to exercise might be a possible determinant of susceptibility to URS in endurance runners.