Is study making you sick?
If you’re anything like me, you’ll have experienced this first hand. You spend four weeks cramming for exams, desperately trying to push as much information into your brain as possible. The whole time, you’re counting down the days until exams are over and you can finally let your hair down for end of exams parties. But almost as soon as you finish exams, your body decides that it’s a wonderful time to get sick. Parties are put on hold in favour of curling up in bed with tissues and cold medication. Sigh.
For me, this happens almost every exam period, so what’s going on? Why is my body betraying me so heinously?
Stress and the immune system
Well, it’s all to do with the influence of stress on the immune system. The immune system helps your body to fight off viruses, bacteria and other harmful entities, all of which are termed pathogens. The immune system tries to maintain a consistent level of low or no pathogen infection.
The relaxed body fights off pathogens through two types of defence:
- Type 1 immunity involves specialised cells which travel around your body gobbling up pathogens and infected cells. This type of immunity is particularly important in fighting off viruses. The action of your immune system in Type 1 immunity has the unfortunate side-effect of causing the cold symptoms you experience, such as a runny nose and fever.
- Type 2 immunity, involves cells producing antibodies which stick to the pathogens and disable them from doing you any harm.
However, when you’re stressed, cells in your nervous system secrete chemicals that act on cells in your immune system to change their behaviour. They increase the amount of Type 2 immunity and decrease the amount of Type 1 immunity. Because Type 1 immunity is particularly important in fighting off viruses, this leaves your body more open to viral infection (Marshall et al 1998).
Many studies have found evidence of such changes in response to exams: when researchers took blood or saliva samples from students during exam periods, they found significantly decreased numbers of the cells and chemicals involved in Type 1 immunity (Marshall et al 1998).
No273 13 Oct 2009 Sneeze by mcfarlandmo http://www.flickr.com/photos/mcfarlandmo/4014611539/sizes/m/in/photostream/ Licensed under Creative Commons
Is your body betraying you?
So if stress decreases your immunity, why don’t you feel sick until after exams are over? It could be due to the fact that stress-suppressed Type 1 immunity is what causes the cold symptoms you experience. When stress levels drop off after exams finish, Type 1 immunity can fire up again to get rid of all the viruses you’ve accumulated, with the annoying side-effect that you start feeling cold symptoms.
So all of this means that your body isn’t really betraying you. While the decrease in Type 1 immunity makes you more vulnerable to viral infection, it also means that you don’t feel any cold symptoms. It seems that your body knows you don’t have time to deal with the symptoms associated with getting rid of viruses while you’re stressed, so it waits until after exams are over.
What can I do about it?
Studies have shown that this influence of stress on the immune system depends on a lot of factors. There have been findings that the more you study, the more likely you are to demonstrate this type of immune suppression, and that this response is more common in students that cram (Murphy et al 2010, Deinzer and Schuller 1998). There have also been findings that such a response is more common in pessimists, and students that are on the pill (Maes et al 1999)
So basically, if you don’t want to get sick at the end of exams, you should probably study consistently throughout semester and stay positive. But if you’ve got to the stage in semester where you’re realising that perhaps you spent a little too much time procrastinating, and you’re bracing yourself for a month of ridiculously intensive study, then there’s still hope. A 2004 study found that immune suppression didn’t happen in students who drank fermented milk containing lactobacillus bacteria (Marcos et al) – maybe you could try eating more yoghurt instead.
Studying by scui3asteveo http://www.flickr.com/photos/scubasteveo/296747958/sizes/m/in/photostream/ Licensed under Creative Commons
Marshall GD, Sandeep KA, Lloyd C, Cohen L, Henninger EM and Morris GJ. (1998) Cytokine dysregulation associated with exam stress in healthy medical students. Brain, Behaviour and Immunity 12: 297 – 307.
Murphy L, Denis R, Ward CP and Tartar JL. (2010) Academic stress differentially influences perceived stress, salivary cortisol, and immunoglobulin-A in undergraduate students. Stress 13: 365 – 370.
Deinzer R and Schuller N. (1998) Dynamics of stress-related decrease of salivary immunoglobulin A (sIgA): relationship to symptoms of the common cold and studying behaviour. Behavioral Medicine 23: 161 – 169.
Maes M, Van Bockstaele DR, Van Gastel A, Song C, Schotte C, Neels H, DeMeester I, Scharpe S, Janca A. (1999) The effects of psychological stress on leukocyte subset distribution in humans: evidence of immune activation. Neuropsychobiology 39: 1 – 9.
Marcos A, Warnberg J, Nova E, Gomez S, Alvarez A, Alvarez R, Mateos JA and Cobo JM. (2004). The effect of milk fermented by yogurt cultures plus Lactobacillus casei DN-114001 on the immune response of subjects under academic examination stress. European Journal of Nutrition 43: 381 – 389.