There have been quite a few times that I would be feeling the onset of flu but a long run or a marathon would somehow stop it dead on its tracks and I feel immediately better after it. 

Last weekend, I had back-to-back races scheduled — a trail run on Saturday and a marathon on Sunday. I had been lacking sleep and a lot of people in the office had been catching the flu. I was not feeling a hundred percent, so I had to make the call to cancel my Saturday schedule and get much-needed sleep.  

I woke up feeling a tad better so it didn’t take me long to decide to pack my bag and head to Clark for the Clark City Marathon (CCM) that night.

The CCM is a series of three races that culminates in a full marathon around this time of the year. The organizer has become a friend so I know how well thought of and organized their races are.

It is also very convenient that the Start and Finish Area is at the Clark Parade Grounds where Filinvest’s Quest Plus Conference Center Clark, my favorite accommodation in the area, is located.

Indeed, it is now hard to imagine that decades ago, this very area was buried in ash and ruin after the 1991 Mount Pinatubo eruption. The US Air Base that once stood there was abandoned, and what remained looked like a wasteland. But from that devastation, New Clark City has emerged and stands as proof of how good urban planning can achieve: a clean, green, and intelligently designed community that hosts world class facilities, thriving businesses, and, yes, beautiful marathon routes.      

Clark will always be one of my favorite places to run. The air is fresher, the roads are smooth and wide, and the entire route felt thoughtfully designed for runners. No traffic, no smog, no chaos — just open space, clean surroundings, and the kind of calm that helps you focus on your stride and breath.

One of my favorite parts of the race was running through the expansive Clark International Airport. There is something surreal about being there in the middle of the night, when there are no flights and the terminal is silent.

We ran up the departure ramp guided only by our headlamps and the rhythm of our footsteps.  It was as if the airport paused just for us runners, giving us that rare chance of owning the space even for just a few minutes.     

Unlike Manila races, where you battle both the distance and the crowd, Clark lets you truly run freely, steadily, and with joy. Every time I run there, I feel exactly what I chase in every marathon: Freedom.

After finishing the race and claiming my medal, I was already feeling stronger, so much better than the day before. Could it be possible that my running was staving off the flu?

So I did a bit of research and the results are quite interesting. There is actually a name for it --- the “Open Window” immune response. It appears that when you do moderate intensity exercise, your body experiences a temporary boost in immune surveillance. Our white blood cells (especially natural killer cells) circulate more actively.  This in turn can help our immune system detect and fight off early viral invaders, possibly stopping a mild flu before it becomes symptomatic.

So if you run before the infection fully takes hold, your immune response might actually suppress it, giving you the impression that the “flu went away.”

Whether true or not, that marathon in Clark made me feel so much better.