For years, scientists believed that long durations of high-intensity exercise (such as marathon running) suppressed the body’s immune system. Recently, researchers have been challenging this notion, arguing that exercise alone can’t be blamed for colds and flu amoung athletes. Still, many runners have gotten a case of the sniffles in the days following their big race, and new research shows that probiotics may provide a solution.
The authors of the study, which was published in the journal Nutrients, argue that strenuous exercise negatively impacts the immune and gastrointestinal systems. These changes, they say, cause short-term immunodepression, increasing your risk for minor infections like colds. Recent research has shown that probiotics can help reduce this risk, so the researchers set out to determine if this is true.
To do so, they gave 14 healthy male marathon runners either 5 billion CFU of a multi-strain probiotic or a placebo for 30 days leading up to their marathon. 24 hours before the race, the researchers measured the amount of cytokines (signalling proteins involved in the immune system) in the runners’ blood and measured their salivary parameters, glucose, and glutamine levels. They measured all of these levels again immediately after the race and again one hour later. The subjects also self-reported symptoms of upper-respiratory-tract infections (URTIs).
The results showed that URTI symptoms were significantly lower in the probiotic group compared to the placebo group, suggesting that a probiotic supplement could help mitigate cold and flu symptoms following a big event like a marathon. While more research needs to be done to determine which probiotic strains are actually helping, if you find you’re constantly battling the sniffles during your training or following your race, talking to your doctor about taking a probiotic supplement might not be a bad idea. Quality and potency can vary widely among brands, so be sure to check with a medical or nutrition professional for advice before grabbing one off the shelf.