Complete 10 obstacle races and it’s likely that after one of them you’ve been ill. Fever, sore throat and vomiting are all common symptoms in the aftermath of any prolonged period of maximal and submaximal exertion across the sporting world. You, as OCR athletes, are exposed to a lot more pathogens in your weekend endeavours than your average racer, and as such are considerably more likely to succumb to a disease.
That said, it’s worth mentioning that a maximal period of exertion is relative to the individual and anyone can get sick through pushing themselves. Similarly, pathogen levels in an event aren’t the be all and end all; throughout hundreds of OCR I’ve been sick once, but have been ill after nearly every marathon, ultra or triathlon. Naturally, these ultra-marathons are more intense on the body but present a decreased pathogenic risk, so why do they hit me harder and what can I do to change the risk of illness to myself?
During intense and prolonged bouts of exercise, the bodies utilization of glucose is distributed between the brain and musculature system with little thought for the body’s immune system. An invisible army of white cells that seek out and kill invading pathogens; i.e. bacteria or viruses.
The metabolism of fats and proteins to provide energy is the last resort for a working muscle and signifies the muscle has burnt through its glycogen stores before sapping the bloodstream of sugars released from systemic stores. While the bodies muscles can convert this trio of fuels into energy, cells of the brain and neural network are unable to do so, relying solely on glucose. This is the same for the immune system.
I repeat the brain, neural network and immune system cannot metabolize proteins or fats for energy, they need a form of glucose.
Note that this article relates to the high-intensity exercise of prolonged duration. An intense park run or short obstacle race is unlikely to drain the glycogen stores within the muscles and liver. However, as the duration increases with the intensity remaining maximal/submaximal the body must start to ration its precious glycogen stores.
Reducing the supply to the muscles would be detrimental to performance and throughout evolution would have likely resulted in a fleeing human becoming dinner. Cutting the brains supply even a little would result in a reduction in comprehension and consciousness, cutting it completely shuts down every major system killing us, but cutting the immune systems glycogen supply? Well, that’s going to do nothing in a short period. So, that’s what we do. We turn of our bodies only defence system to the most dangerous of threats we face.
Specifically affecting the immune system chemicals released from damaged muscle cells during exercise actively signal immune suppression. Chemicals such as cytokines and reactive oxygen reduce the body’s production of all white blood cells reducing our circulating volume, further weakening our defense’s. More than just reducing circulating volumes cellular modifications occur at recognition complexes on macrophages, (a vital white blood cell). This mutation can allow some pathogens to hide within our own immune cells, avoiding detection and replicating without limitations in movement.
This all sounds extremely terrifying, but in reality, the most common invading pathogens are likely to be ones that cause a cold or a sore throat.
While the body is extremely complex it can easily be manipulated to prevent, complete immune shut down. If the main contributing factor is the absence of glucose then supplementing glucose throughout exercise is the simplest way to help your immune system stay on track. Keeping blood sugar levels up will prevent the body burning its glycogen stores and having to ration its fuels between only the brain and muscles. Your immune system will thank you although you may not know it.
As vital as intra glucose supplementation is our nutritional preparation is equally important in the week leading up to any event. ‘Carb loading’ is often used primarily to ensure the muscles are fed and have plenty of glycogen stores. Glycogen stores that stop muscles dipping into your immune systems supply. Carb load right and you can prevent or dramatically reduce the impact intense exercise has on other functions of the human body.
Finally, and perhaps most importantly is recovery. Sometimes there will be events that simply go beyond the body’s ability to absorb glucose and regulate glycogen stores. You will shut off your immune system and that’s okay, but be smart about your recovery processes.
It is often said that a can of full-fat coke can prevent you getting sick after a race. There is little evidence to support this, no individual chemicals have been found to interact with the immune system and it's widely regarded as a myth in most circles. However, I’ll tell you what coke has in abundance. Glucose.
Upon completion of the exercise, the immune system doesn’t magically turn itself back on. The complete mechanism remains unknown but it appears that once the brains glucose levels are restored it’s reactivated. Again, this isn’t immediate and dependent on your recovery process and nutritional intake can take from anywhere from 3-72 hours. That’s potentially a 72-hour pathogenic window for every virus or bacteria you know to float around your body multiplying and causing damage.
And you wonder why you get a sore throat or a cough?
Feeling under the weather and thinking about your race this weekend?
Look, you know your body and what it can take allot better than I do. But if you’re already ill, fighting off an infection or virus do you really think that shutting off your immune system for 1-3 days is wise? Just because you stop doesn’t mean the virus will and you’ll only get sicker. Save your energy for the White Cell army coursing through your veins, fighting for recovery and grant them some rest.
Be smart and look after your immune system, it’ll last a lifetime. And that lifetime length depends on how well you treat your invisible army. Carb load, supplement and recover with a glass of coke, chocolate milk or whatever you prefer. Allot more is damaged during exercise than just your muscles, and allot more has to recover. Again, be smart and look after your immune system.