3.1 Infectious rhinitis
Viral rhinitis or ‘common cold’ is one of the most common diseases worldwide and it was the principal reason for athletes to consult a doctor during both the Summer and Winter Olympic Games of 2000-200222, 23. Interestingly, elite athletes suffer more frequently from commons colds compared to recreational athletes24 and they were more common in athletes with pre-existing nasal symptoms 3. Data suggests that long-distance running increases the likelihood of having a common cold during heavy training or in the period following a marathon24-28. These findings imply a potential link between acute physical stress and susceptibility to upper respiratory tract infection. An exercise-induced decrease in immunoglobulin (Ig)A secretion is the most commonly reported explanation, although a study from Peters failed to show this link 28. Other mechanisms that have been suggested are a decreased NK-cell activity and/or lymphocyte proliferative response after strenuous exercise29, but clear evidence is lacking. Also, it should be noted that in 30-40 % of studied cases no pathogen could be identified2, so the infectious component might be overestimated and other causes might lay at the base of the nasal dysfunction.