12 . 2019
Jess Barber (B. Nutrition and dietetics) shares an important message on the way stress interacts with the human body and how you can combat it
A simple google search tells us stress is, “a state of mental or emotional strain or tension resulting from adverse or demanding circumstances”. When you’re stressed – emotionally or psychologically, the sympathetic nervous system is involuntarily aroused, and the body enters our ‘fight or flight’ response. This response begins in the brain, with the hypothalamus, telling our adrenal glands to release stress hormones, adrenaline, and cortisol.
Overall these hormones:
Cortisol causes the body to instinctively shut down into protective mode and shuts down all of the nonessential systems, such as our immune response and digestion. Which, when you think about it, makes sense. If we are running away from a tiger, you don’t want to be devoting energy to fighting off a virus or digesting your breakfast. It prioritises all of the bodily systems needed to respond to the emergency, such as your muscles and heart.
When the stressor is removed, the hypothalamus will stop sending signals and all systems should return back to normal (homeostasis). The stress response becomes an issue when you are experiencing prolonged stress and negative physiological effects occur. The ways in which stress effects the different systems and processes in our body is outlined below.
Research is constantly being conducted to understand how stress impacts inflammation in the body (Cohen., et al. 2012). Cohen et al. (2012) found that chronic psychological stress is associated with the body losing its ability to regulate the inflammatory response.
As mentioned, when we are stressed, cortisol is high. Among its many roles, cortisol also plays a role in regulating inflammation.
So, when stress is prolonged, it alters the effectiveness of cortisol in regulating the inflammatory response. HOW? Our immune cells become insensitive to cortisol’s regulatory effect and as a result inflammation occurs.
Dorshkind & Horseman (2001) showed that stress has an immunosuppressive effect – that is, immune system is down regulated when an individual is stressed. Again, cortisol plays a role. Cortisol does not usually cause harm to the immune system, however, when experiencing chronic stress, cortisol is present in the blood for a prolonged period of time and has been thought to interfere with the production of the antibodies (the good guys which target foreign particles). Additionally, cortisol can decrease the number of lymphocytes (our protective white blood cells) putting you at risk of viruses like the common cold.
Also, when we are stressed, we are more likely to have unhealthy coping mechanisms such as drinking, smoking, or eating unhealthily, which can have an indirect effect on our immune system.
To understand the effect of stress on the gut we must first understand that the gut and brain are intrinsically linked. There is a bidirectional network which connects the brain and gut. Because of this network, signals from the brain can affect the functions of the gastrointestinal tract and visceral messages from the gut can impact the brain (Allen, Dinan, Clarke, & Cryan, 2017).
When the brain recognises an external source of stress and the sympathetic nervous system is activated energy is borrowed from the gut. The digestive tract is of low priority when in ‘Fight or flight’ mode and so blood flow to the gut is reduced. Other changes to gastrointestinal function include:
These changes can trigger gastrointestinal symptoms, including abdominal pain, bloating and changes in stool consistency.
Not only can stress affect the digestive tract as a whole, it can also affect the trillions of microbes within the gut, specifically the large intestine. These microbes work together to keep your body thriving.
Interestingly, Allen, et al., (2017) showed that long term chronic stress can reduce the variety of bacterial species in our gut. Variety within the gut microbiome is KEY to our health. Greater variety equals greater health outcomes.
Clinical studies have shown that stress can also reduce the number of good bacteria that help signal the correct response to the brain to cope with and protect you from the physiological effects of… you guessed it, stress. Fortunately for us, stress is manageable, and with healthful decisions, the microbiome can be altered for the better giving us the chance to live, look, act and feel our best (Allen, et al., 2017).
Our stress hormones cause our blood vessels to constrict and divert more oxygen to our muscles and essential organs. When our blood vessels become narrower, our blood pressure increases. This puts great strain on our heart, forcing it to pump harder and faster, putting us at risk of greater cardiovascular consequences such as a heart attack (Dimsdale, 2008).
Ever notice your neck and shoulders become super tight or you get a migraine when you’re going through a stressful period? That’s because when we are under stress our muscles become tense in an attempt to protect ourselves from injury. If you are under constant stress, your muscles are constantly tight which can be the cause behind your headaches/migraines, and bodily aches and pain.
Personally, the first question I ask myself is; ‘why am I stressed’. Then I ask, ‘can I change it’? If I can, I start mentally or physically writing the actions I can take to reduce this stress. However, sometimes we can’t change things and may have to temporarily deal with a source of stress. When this is the case, and my mind is super busy, there are a few coping mechanisms I adopt. I do not have a set routine I run through when I feel stressed; Instead, I find having multiple little practices best equips me to deal with different sources of stress.
So… a few things I turn to:
I also like to remind myself to let go, to not overthink things, to not attach to my thoughts, to not take things to seriously and when in doubt, just breathe…
“The most evidence-based stress management technique is the natural act of abdominal breathing”.
Cohen, S., Janicki-Deverts, D., Doyle, W. J., Miller, G. E., Frank, E., Rabin, B. S., & Turner, R. B. (2012). Chronic stress, glucocorticoid receptor resistance, inflammation, and disease risk. Proceedings of the National Academy of Sciences of the United States of America, 109(16), 5995-5999. doi:10.1073/pnas.1118355109
Dorshkind, K., & Horseman, N. D. (2001). Anterior pituitary hormones, stress, and immune system homeostasis. Bioessays, 23(3), 288-294. doi:10.1002/1521-1878(200103)23:3<288::AID-BIES1039>3.0.CO;2-P
Allen, A. P., Dinan, T. G., Clarke, G., & Cryan, J. F. (2017). A psychology of the human brain–gut–microbiome axis. Social and Personality Psychology Compass, 11(4), e12309-n/a. doi:10.1111/spc3.12309
Dimsdale, J. (2008). Psychological Stress and Cardiovascular Disease. Journal Of The American College Of Cardiology, 51(13), 1237-1246. doi: 10.1016/j.jacc.2007.12.024