Anxiety and Mood Disturbance Are Prospectively Associated With Respiratory Infection Risk and the Mucosal Immune Response to Exercise

We prospectively examined whether psychological factors influence (a) respiratory tract infection (RTI) risk and (b) the mucosal immune response to exercise. In Study 1, n = 406 adults (67% male) recorded RTI symptoms for two weeks before and after a marathon. In Study 2, under controlled laboratory conditions, n = 45 adults (51% male) completed 60 min of running at 65% V̇O_2peak (EX) and seated rest (CON) in randomised order. Anxiety, total mood disturbance (TMD) and perceived psychological stress were measured before exercise. Saliva collected pre- and post-exercise was analysed for secretory immunoglobulin A (SIgA). Fifty runners suffered an RTI post-marathon. Runners prospectively reporting high trait anxiety or TMD were more likely to suffer an RTI post-marathon (OR [95% CI] = 1.06 [1.02–1.11] and 1.04 [1.01–1.07], respectively). Higher trait anxiety and TMD were associated with a greater reduction in saliva SIgA (p < 0.05). There was no association between mucosal immunity and RTI risk (OR [95% CI] = 1.00 [0.97–1.01]). In Study 2, despite no significant difference between EX and CON (p > 0.05), psychological factors were associated with the SIgA secretion rate response to exercise in men (trait anxiety, state anxiety, TMD, psychological stress: r = −0.55, −0.65, −0.61 and −0.66, respectively; p < 0.01). In conclusion, anxiety and mood disturbance were prospectively associated with infection risk after a marathon and the mucosal immune response to exercise. Athletes should optimise psychological well-being to support immune health. Researchers should take account of psychological factors when examining the mucosal immune response to exercise.