Your marathon brain could be making you sick
Research hints your pre-race mood might matter more than you think
Maybe you’ve experienced it: you cross the finish line of your marathon feeling strong, only to wake up a day later with a sore throat and a headache. It turns out the problem might not be the race itself, but everything swirling in your head beforehand. In a study published in the European Journal of Sport Science, a group of researchers from Liverpool John Moores University and Bangor University set out to understand why so many runners catch a cold after a marathon, and the answer wasn’t just about hard training days and logging big mileage.
Inside the pre-run mood check
The group followed more than 400 marathoners in the weeks before a race. Along with the usual performance and training questions, the runners reported how they were feeling emotionally—anxious, calm, irritable, keyed up. They also gave saliva samples both before and after the race. Then the runners logged how they felt over the next two weeks, including any cold-like symptoms. The researchers were looking at markers tied to what’s called mucosal immunity, basically the first-line defence in your mouth and throat against the viruses that cause common colds.
The link between nerves and getting sick
The researchers observed a clear pattern. Runners who reported higher stress, anxious thoughts or unsettled moods before the race were more likely to experience a dip in mucosal immunity, and they were also the ones who tended to contract a cold after the marathon. The researchers conducted a second, smaller study in the lab, this time using an hour-long treadmill run, and observed a similar effect, particularly in men. If your stress levels were already running high, the body’s first line of defence didn’t bounce back as smoothly.
The story was less straightforward in women, likely because hormones, cycle phase and contraceptive use can all influence immune markers. The researchers were clear that more work needs to be done there.
How stress and long runs team up
The takeaway isn’t that running makes you sick. It’s that psychological stress and physical stress can pile on top of each other, and when they do, your immune system sometimes pays the price. Long runs and the race build-up already nudge your system, and if you’re also juggling nerves, poor sleep, hectic travel or life stress, that nudge gets a little stronger.
What you can do about it
None of this was meant to scare anyone away from running long. The researchers were clear that regular training still lowers your overall risk of getting sick, but they also suggested treating your stress levels with the same respect you give your fuelling plan or your long runs.
Simple things help: sleep a bit more in the week leading up to the race, clear out any avoidable stress and try a few easy relaxation habits if you know you run “hot” emotionally. Sorting out travel ahead of time and giving yourself extra breathing room on race morning go a long way, too.
