Athletes engaging in prolonged intense exercise may be more susceptible to upper respiratory tract infection (URTI), than individuals participating in moderate or no exercise. Elite rugby union players can train for approximately four hours per day, 5 to 6 days per week with competitive matches once a week. This intensive training schedule may place these athletes at increased risk of URTI and suppressed immune function, while at the same time increasing exposure to pathogens.
A recent randomised control trial has shown support for the hypothesis that probiotic supplementation will reduce the duration of illness symptoms (sneezing, sniffing, sore throat, cough, congestion, gastrointestinal symptoms- nausea, vomiting, diarrhoea, headache, boils, skin infections, itchy watery eyes) amongst elite rugby union players. The trial demonstrated that probiotic (acid resistant strains: lactobacillus gasseri (2.6 billion CFU); Bifidobacterium bifidum (0.2 billion organisms); Bifidobacterium Longum (0.2 billion organisms) supplementation ingested at a daily rate of 3.0 x 10 (9) colony forming units (CFU), reduces the incidence of infectious symptoms in highly trained rugby union players. Of particular note, those athletes that partake in intense training and competition schedules. One of the most interesting findings from the study was that there is a significant reduction in the number of URTI and Gastrointestinal (GI) symptoms for the athletes in the study on the probiotic intervention compared to placebo. Of the 30 individuals in each group (30 probiotic, 30 placebo), 14 of the 30 athletes in the probiotic group never experienced URTI or GI illness during the 8 week trial, whereas only 6 of 30 in the placebo group escaped URTI and GI illness.
Moreover, the study reported a significant reduction in the number of days an athlete presented with infection in the probiotic group compared to placebo, indicating positive clinical consequences, which provide evidence for the beneficial effects of daily supplementation with the above probiotic strains in highly trained rugby league players.