Long runs and depressed immune system

Of course, there are more important things to be thinking about right now other than running.

Marathon disappointment

For many runners the first and biggest effect of the coronavirus outbreak was the cancellation of the spring marathons. Training for a marathon involves dedication and plenty of time out running. The marathon itself provides motivation to train in all weathers; to get out there and run yet another long and demanding run.

It’s no surprise then, when those cancellation notifications started dropping into people’s mailboxes, the disappointment was huge. Social media was full of comments about wasted training and various levels of ‘guttedness’. After the initial shock, attention turned to how to ‘use’ all those marathon miles in the bank. Dates for alternative ‘unofficial’ 26.2 runs were being suggested, even with offers of aid-station provision. Subsequently, with announcements of social distancing, any thoughts of getting together to run the distance soon evaporated.

What to do now? Still keen to salvage some form of training outlet, attention turned to virtual runs. Mapping and tracking runs of marathon distance individually and comparing results with other similarly affected runners. Surely nothing could scupper that.

Endurance running and infection

But, wait. Who has ever run a marathon and come down with a cold or worse just days after? Me for one, and not just once either, I almost expect it. Indeed research tells us that after the Two Oceans Marathon (56km), a third of the randomly sampled group who ran the race reported suffering upper respiratory tract infection (URTI). A further study seemed to confirm runners’ susceptibility to infection after long bouts of exertion. The common notion of depressed immune function and the ‘open window’ for infection of 3-12 hours after prolonged exercise has been accepted by coaches and runners for years.

However, more recent research defines this phenomenon as a myth. Debunking the Myth of Exercise-Induced Immune Suppression: Redefining the Impact of Exercise on Immunological Health Across the Lifespan suggests that we should question accepted wisdom regarding the effects of endurance running on the immune system. The study explains that there can be other reasons for infection aside from a depressed immune function. The critical review of over 200 papers stated: ‘To this day, the “open window” hypothesis continues to be discussed despite the existence of contradictory evidence’.

People get ill after attending mass gatherings that have nothing to do with exercise; simply being in close proximity to many other people increases our risk of catching something. And what about all those high-fives that runners pick up along the route? The authors conclude: ‘it is unlikely that vigorous and prolonged exercise heighten the risk of infections’. 

The trouble with science

Science is fickle. One study can prove a theory whilst another will disprove it. The internet gives us access to a never-ending source of both information and misinformation. How do we know what to believe? The way science is published is usually very technical and makes it very easy to misinterpret. Research studies are often presented to the public as abstract; a very truncated version. There are many people who write about very complex issues who are not experts in their fields or the subject matter they write about. 

Implications for runners and coronavirus

Let’s get one thing straight. Exercise and running at less than extreme intensity and distance levels are great for the immune system. Runners are, because of their fitness, generally better able to cope with infection than most. Running is also great for mental health and well-being, a real benefit in present times.

The question mark appears over long runs (long being 90 minutes and more) and very high-intensity workouts. You can read the literature and draw your own conclusion. It may or may not be correct. However, it was pointed out to me today the importance of erring on the side of caution. If you adopt the conventional thinking of immunity depression, then you will probably be taking it fairly easy in your training. No 20-mile runs for you. Conversely, if you think it’s a myth, and the more recent study makes perfect sense (and why not because it presents compelling arguments), then you might run that virtual 26 miler and ignore the warnings. You might try and keep your marathon fitness by continuing to run those extended workouts, in the hope that sooner, rather than later, an opportunity will arise for you to finally run your marathon (good luck with that).

But what if you are wrong? It’s very easy to be wrong, even the experts don’t agree. What is the safer thing to be doing? For me, I’m happy that my spring marathon journey is complete. I’ve done most of the training and I’ve benefited from it in more ways than just increased fitness. I’m going to give those long and depleting runs a rest for now. I’m going to enjoy my running and feel blessed that I am able to get out there for some much-needed running therapy.