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Asked by anon-252718 on 11 May 2020.
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Maria Marti answered on 11 May 2020:
Good question! Stress is a very useful mechanism by which our bodies can get in alert mode in case of imminent danger by starting the so-called ‘fight-or-flight’ response. When we get stressed, a region in our brain called the amygdala starts an hormonal response that promotes changes through our whole body that are very useful to run away or fight in a dangerous situation. For instance, these hormones ensure that more blood flows into our muscles, that we breathe faster and our heart beats more often, and that more nutrients get released into the bloodstream. They also stop non-essential functions such as digestion. The problem comes when we are constantly stressed, as a stress response that lasts for an unnecessary amount of time can affect our digestive and cardiovascular systems and also cause anxiety and sleep problems.
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Theresa Wacker answered on 11 May 2020: last edited 11 May 2020 12:31 pm
Hi there,
that is a very good question! I am not a neuroscientist, nor have I studied human physiology much, but I will try to answer as best as I can. I am sure some other researchers here can say a bit more about this. But it is a really cool and interesting question, so I will try đ This is what I know:
First of all, short term stress that is related to an event like an exam or competitive sports is different from chronic, long term stress, like when you have problems at home over long stretches of time or get bullied etc.. Short time stresses can be referred to as eustress – good stress and distress – bad stress. Good stress helps you focus and react fast to a situation. However, when stress becomes chronic, like in distress, it can indeed affect your brain and cause areas of it to change and can also affect the immune system. When you get stressed, it activates your so called Hypothalamus (an area of the brain)-Pituitary(a gland in your brain that releases stuff)-Adrenal (a term that refers to some more glands in your body)-Axis. This axis leads to the production of Cortisol, a hormone, which is then released and primes your body for instant action: fight or flight. It increases for instance your blood pressure and blood sugar levels. It also suppresses inflammation. This is all well and good when stress occurs for a short time; there, it enables you to deal with effectively with a stressor you encounter. Chronic stress, on the other hand can lead to chronically high cortisol levels. That is not good for your heart, metabolism and immune system…and your brain. Chronic stress increases the activity level and connections in your amygdala, which is your fear center in the brain. The electric signals in your hippocampus, which is important for learning, memory and stress control, deteriorate (get worse). Since the hippocampus also controls your stress response, this also means chronic stress makes it harder for you to control your stress. High levels of cortisol over long times can also shrink your prefrontal cortex, which is important for controlling behaviour, concentration and decision making. In areas of your brain that are important for forming memories, less neurons are made, which means it becomes harder to learn and remember things. As you can see, there is lots of areas of the brain affected by stress.
There is many more effects, but I hope that gives you a first overview đ -
Jonathan Benn answered on 11 May 2020:
This is a great question! As someone who primarily works with brains Iâll focus more on how stress affects the brain, but hopefully someone else will be able to add onto this đ
Our response to stressful situations has evolved from the âfight or flightâ response that allows us (and many other animals) to respond quickly and appropriately when we find ourselves in dangerous situations. This kind of response was made to deal with short term stress and raises levels of certain hormones that increase energy (glucose) levels and heart rate, allowing us to respond faster to any immediate danger!
The more permanent, and negative, effects of stress on our brains and body are caused when we experience prolonged (chronic) periods of stress. The response I mentioned before is continually active in chronic stress, and causes the hormones to stick around for much longer in the brain and body. This prolonged exposure affects how the cells of the brain communicate, and locks them in a more vigilant and reactive state which heightens the likelihood of various mental health conditions such as anxiety and depression. Our immune system is also weakened by chronic stress, which has affects throughout the body and brain, increasing the likelihood of catching an infection.
An interesting thing about long term stress is that it changes in how a personâs DNA is interpreted by the body, and these changes can even be passed down to that person’s children. There are lots of cases showing that chronic stress experienced by mothers can cause various negative affects to their children. A famous case of this is the âHugerwinterâ famine experienced by the Netherlands in the second world war. Mothers giving birth during this time were experiencing horrific chronic stress due to the famine, and the children born ended up experiencing higher levels of obesity, diabetes and schizophrenia, believed to be due to the stress experienced by their mothers being passed down to them in their DNA.
Hope this answers your question to some extent but please let me know if thereâs anything youâd like any more detail on! -
Anabel Martinez Lyons answered on 11 May 2020:
Hi, and thanks for your question! Stress â especially when we experience it on a regular basis â takes a big toll on our brains and bodies. Stress in the short-term can make us feel irritable and tired, or highly emotional, and has been shown to significantly impact our ability to focus. It can also result in some physical effects like chest tightness, rapid breathing, feeling cold and/or shaky, feeling nauseous or getting headaches. Chronic stress (over time) can have greater effects on our brains and bodies; it can greatly interfere with our sleep patterns and eating behaviours, in turn leading to weight gain or loss, poor nutrition and effects on the growth/healthiness of our hair, skin, and nails. Chronic stress has also been found to lead to worsening of some health conditions, like diabetes, heart disease, stomach/gut problems and some mental illnesses for example. Specifically regarding the brain, chronic stress has been shown to cause changes in the ratio of white to grey brain matter in some brain regions, and this can in turn affect our memory, our abilities to regulate our emotional responses, and even our metabolism. Hope you find this answer helpful!
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Candice Ashmore-Harris answered on 11 May 2020:
Stress is a natural reaction to both everyday events that everyone experiences (like being on time for the bus to school) and major life events (like the death of a loved one). In small amounts it can be beneficial and help you to cope with challenging situations.
Your central nervous system is in charge of the stress response (also called the ‘fight or flight’ response). The hypothalamus, a small region of the brain, tells your adrenal glands (which lie above the kidneys) to release the stress hormones adrenaline and cortisol. These hormones increase your heartbeat and send blood faster to the areas that need it to respond to the stress (such as your muscles, heart, and other important organs).
When the perceived fear (or ‘stressor’) is gone, the hypothalamus should signal to the adrenal glands and other systems to return to the levels before. If the central nervous system doesn’t return to normal, or if the stressor remains, the response will keep going and this long term hormone release can have many impacts on different parts of the body and behaviour.
For example, long-term stress can cause your liver to release more sugar into the bloodstream than is needed which can raise your risk of diabetes. It can also make you more easily irritated, can affect your sleep and your ability to fight off illnesses by weakening the immune system – amongst many other impacts. There’s a great image that shows you all the areas of your body that can be impacted if you have high stress levels over the long-term here: https://www.healthline.com/health/stress/effects-on-body#2
It’s not all doom and gloom though! Exercise and laughter are both great proven ways to lower stress levels.
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Roberta Migale answered on 11 May 2020: last edited 11 May 2020 4:06 pm
Hi thelocalnerd26, fantastic question! Even though we are all familiar with the idea that stress is bad for our bodies..it was not until a short while ago in 2012 that the best evidences on how stress is affecting our bodies was found. A study by Sheldon Cohen at the Rockefeller University has found what stress is doing to our bodies: undermining the bodyâs capacity to deal with inflammation. But let me tell you in one line what inflammation is. Inflammation is a normal response of our body to damage (for example if you exercise too hard you may have inflammation in your muscles), to bug (for example you may have inflammation when you get a cold). Inflammation is good for our bodies because upon its activation our tissues can heal faster allowing our bodies to recover from a damage or a illness. What scientist have found is that when people are stressed for a long period of time, their bodies cannot turn off properly the normal inflammation that may occur if for example they were to catch a cold. Imagine, the idea is that a person which is very stressed all times will likely have some problems with their inflammatory response and this makes it easier for these people to develop illnesses such as diabetes, asthma as well as making other diseases already present in the person much worse. Although this is one study, it is strikingly the first to shed some light on the longstanding idea that stress is bad for our bodies because it actually shows the biology behind it, which I find fascinating. I hope it helps!
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Nina Rzechorzek answered on 12 May 2020:
Hi the localnerd26 – the others have already provided lots of great answers so I’ve just listed below some useful resources for further exploration! All I will add is that some stress is necessary for daily survival, and our ‘stress axis’ (aka ‘HPA axis) has a diurnal rhythm such that the steroid hormone cortisol peaks in release just before we get up everyday – this helps prepare our bodies and minds for the active part of the day and is a completely normal physiological phenomenon. When our body clocks are disrupted however, this can lead to mistimed activation of the HPA axis which contributes to the ill effects of circadian disruption (including the symptoms of jet lag!).
https://www.apa.org/helpcenter/stress-body
https://www.health.harvard.edu/mind-and-mood/protect-your-brain-from-stress
https://www.nuffieldhealth.com/article/resilience-how-stress-affects-your-body-and-brain#about -
Julia RamĂrez answered on 12 May 2020:
Hi @thelocalnerd26! I can only speak from a cardiovascular perspective. Stress normally activates the sympathetic nervouss system, which in turn accelerates heart rate and increases blood pressure, for example when we exercise. This effect goes away after the stressor (exercise). If we are then under continuous stress, emotional, for example, we can have chronic effects in the heart and cardiovascular system, which leads to heart failure and more severe conditions.
Comments
anon-252718 commented on :
Thanks for the replies. but how does stress weaken the immune system? Is it because the brain is too busy trying to deal with the threat that it needs more nutrients so it steals it from other organs?
Stay safe! đ
thelocalnerd26
Nina commented on :
Great follow-on question – it’s mainly because prolonged over-activation of the HPA axis (and thus persistently high levels of cortisol) leads to the suppression of the immune system. It kind of makes sense in evolutionary terms for acute stress – you don’t want to be investing energy in immune responses when you’re trying to run away from a predator for example. We use this immunosuppressive effect of steroid in the clinic to treat inflammatory conditions that are caused by a ‘hyperactive’ immune system – we call these ‘immune-mediated diseases’ and there are many. We have to be careful with the doses and long courses of treatment – and it’s also very dangerous to stop this kind of steroid treatment too quickly so we always have to ‘taper’ it gradually. Here’s another video to help: