No Flu For You!

How to outwit bugs

No one likes getting sick. But the stakes are particularly high for runners, because even minor training disruptions can leave your goals out of reach. Earlier this year, Norwegian sports scientists published an analysis of nine years of training data from their world-beating cross-country ski team. The Olympic or world championship medallists in the study reported an average of 14 days per year with symptoms of respiratory or gastrointestinal infection; the other athletes, among the best in the world, reported 22 sick days per year. Dodging an ill-timed bug, in other words, might be the difference between podium and also-ran.

There are some obvious steps you can take to lower your risk of infection in winter: wash your hands frequently, get plenty of sleep, eat well, stay hydrated, and so on. There are also some less obvious matters to consider: US ultra runner Sage Canaday finds he’s most vulnerable when he heads to a crowded (and germladen) public space after a long run in cold weather. Keep these measures in mind if you’re training hard now.

BEWARE OF AIR TRAVEL

In the Norwegian study, athletes were five times as likely to report symptoms the day after a flight, and the risk stayed elevated for up to a week. In addition, their risk of infection tripled the day after a race. As a result of the study, Norwegian skiers are now advised to wait a day after racing before flying home. That may not be practical for everyone, but the same general principle applies. After a race, or after air travel, give yourself at least one easy day before jumping back into training. And if you’ve raced and flown, take the next day completely off – and consider it not a rest day but an investment in your health.

FUEL THE LONG RUNS

The hard and continuous training that’s required to chase PBS can leave your immune system in a weakened condition. And research suggests that the length of the run, rather than its intensity, matters most: in a recent study, two hours at a moderate pace dampened immune function more than 30 minutes of intense running. Taking in carbohydrates during and after long runs can help fight off a rise in immune-suppressing stress hormones. If you’re running for longer than 90 minutes, plan to have a sports drink or gel; and after any long or hard workout, refuel with carbohydrates and protein in a four-to-one ratio – a peanut-butterand-banana sandwich with a glass of milk, for example.

MIND YOUR LEVELS

Even though the Norwegian skiers did their heaviest training before their winter racing season began, they were most susceptible to infections toward the end of winter. A possible culprit is the seasonal variation in vitamin D, which is primarily gained via sun exposure. A recent analysis concluded that to minimise the risk of infections, athletes should aim for 75 nmol/l of 25(OH)D (the marker of vitamin D measured in blood tests) rather than the usual target of 50 nmol/l. Fatty fish, eggs and fortified milk provide some vitamin D, but the researchers also recommend taking 1,000 IU per day of vitamin D3 supplements in winter.