A guest article by Zara Mohseni
Exam season is around the corner. Stress levels across campus begin to rise. Some people handle this pressure reasonably well and others start spiralling into full-on crisis mode as finals loom. Guest author and molecular biology student Zara explains the interference of exam season and sickness.
You’ve been sitting in the library far too long, living off of questionable vending machine coffee from the UB, and now you’re feeling drowsy, drained, and just… off. There’s also a strangely universal experience, the day before your big oral exam your throat starts to feel “weird”. You’ve got a headache and suddenly it feels like you’ve been run over by a bus. You probably caught a cold. It’s no secret that stress can weaken your immune system. What fewer people realize is that stress can also wake up microbes already inside you. Some of these “sleeping” microbes have been with you for years, living rent free inside your cells and you never noticed. They cause no day-to-day symptoms, but when your body’s defences are lowered, you might start feeling their presence.
This semester was really special to me, because I’ve been on an exchange at Radboud University in the Netherlands. My favourite course by far was the “Infectious Diseases” course. It was the only class that could get me out of bed at 6:30 every week. Some of our lectures were connected to the university medical center where infectious disease research is a major focus. Some of the professors came straight from the clinic to teach and share their up-to-date research with us. I remember sitting there, fascinated by how passionate they thought about their work. We dove into the intricate world of pathogens (germs), how they evade your immune system and sometimes stay hidden inside you. I left each lecture thinking, “More people should actually know about this stuff”.
The hidden passengers
Over 90 percent of adults worldwide carry the Epstein-Barr virus (EBV). It lives latently inside your B cells, the immune cells involved in producing antibodies. Typical reactivation signs can include a sore throat, fatigue, and swollen glands, although in many healthy people episodes are so mild they can pass unnoticed. Stress is one of the triggers that can tempt it out of hiding. Usually, EBV keeps a low profile by producing only just enough proteins to stay unnoticed by your immune system. But when our defenses weaken, reactivation is easily mistaken for flu or a typical cold.
Another familiar intruder is HSV 1, the herpes simplex virus type 1. Nearly two thirds of people under 50 carry it in clusters of nerve cells. When active, it often shows up as fluid filled blisters that break and crust over. Many think they’ve “caught it again”, but in reality, the virus never left, it just masked itself from your immune system and waited for the right moment.
Latency is the biggest trick in the viral playbook. When a virus can’t outfight your immune system or sustain replication, it hides in your cells and keeps as quiet as possible. It settles in, manipulating your immune tactics to avoid detection. Some viruses take it a step further by integrating their genome into your own DNA, like HIV does. With HIV, this “silent” phase differs from the classical latency seen in herpesviruses. The virus can remain integrated and inactive for a time, but can resume replication later. Once it’s part of your genetic material, you can’t simply target and destroy it without harming yourself, so treatment aims at “damage control”.
Your defence army
Most of the time, your immune system shuts down any attempt at viral reactivation before it even gets going. It’s a defence network so clever and adaptable that even Napoleon’s Grande Armée wouldn’t stand a chance. Think of it as a carefully coordinated unit with plenty of “special forces”, each trained for a different job, but all able to work together without missing a beat. You’ve got Killer T cells and natural killer (NK) cells doing the patrols, on the lookout for infected cells.
Antibodies are able to block viruses before they spread through your whole system. Your skin, plus the lining inside your mouth and nose, do a lot of the heavy lifting when it comes to keeping unwanted visitors out. On top of that, you’ve got chemical defences at work, things like enzymes in saliva, the harsh acid sitting in your stomach, and antimicrobial peptides. They’re all busy dealing with pathogens before they get comfortable. Side note: smoking is a sure way to weaken these natural clearance systems. If your immune system is already under strain, it’s a good time to ease off and give it a chance to do its job.
What stress does to this system
Stress triggers the hypothalamus to release CRH (corticotropin releasing hormone). This sets off a signalling cascade, resulting in your adrenal glands releasing cortisol. A very common misconception is that cortisol is your enemy, but cortisol is your friend, as it helps control inflammation short term. However, long term or chronic cortisol influx disrupts immune coordination. It suppresses T helper cell activity, reduces antibodies that help prevent entry (secretory IgA) and alters the overall balance of inflammatory cells. Weak surveillance means more opportunities for latent viruses to replicate again or for new ones to appear. Risk factors such as a crowded library can add fresh microbial exposure on top of reactivation risk.
A study of healthy Cambridge University students (Turner et al., 2020, Scientific Reports) showed just how much exam stress can alter the immune system. Within weeks, measurable shifts in immune cell populations were observed. The number of certain cells increased might sound good, but more isn’t automatically better. B cell numbers rose significantly, which matters because EBV hides in them, while helper T cells dropped, the very coordinators that help keep latent viruses quiet. Function can fall even as quantity rises. That imbalance can loosen the control we normally keep over long-term viral passengers.
Why people misinterpret it
The symptoms of reactivation can look just like illnesses you have had many times before. A slight fever, feeling more tired than usual, a sore throat, perhaps a faint rash – and yet, most people simply assume it is another cold. Realistically, without the proper testing, it is really difficult to tell whether it is a new pathogen or a virus that has quietly been in your body for years. In many cases there are no clear symptoms at all, so the whole process can unfold unnoticed.
Stress is constant, even if you cannot feel it. Change begins deep in the body long before you realize something is happening. Students often keep going until their body simply throws in the towel. And naturally, it will do this exactly when you need your brain to work. This is why it’s important to take care of your body. Get up from your desk once in a while. Eat meals that are not instant noodles. Drink water before the UDE coffee machine claims your soul. Go outside, even if it’s grey and rainy. Sleep enough so your killer T cells can recover, and stay hydrated, so immune cells can move where they’re needed. Just pay attention to the simple everyday habits. At the end of the day you’re not just protecting your grades, you’re also stopping yourself from becoming part of the next flu statistic on campus.
Source:
Turner, L., Galante, J., Vainre, M. et al. Immune dysregulation among students exposed to exam stress and its mitigation by mindfulness training: findings from an exploratory randomised trial. Sci Rep 10, 5812 (2020).
https://doi.org/10.1038/s41598-020-62274-7
