What is Stress?

Have you ever found yourself in a situation where your to-do list seems endless, deadlines are fast approaching and you find yourself saying ‘Eek! I feel stressed!’? But what is stress really, and how does it affect us?

Firstly, let’s debunk one myth: stress is not necessarily a ‘bad’ thing. Without this brilliant ability to feel stress, humankind wouldn’t have survived. Our cavemen ancestors, for example, used the onset of stress to alert them to a potential danger, such as a sabre-toothed tiger.

Stress is primarily a physical response. When stressed, the body thinks it is under attack and switches to ‘fight or flight’ mode, releasing a complex mix of hormones and chemicals such as adrenaline, cortisol and norepinephrine to prepare the body for physical action. This causes a number of reactions, from blood being diverted to muscles to shutting down unnecessary bodily functions such as digestion.

Through the release of hormones such as adrenaline, cortisol and norepinephrine, the caveman gained a rush of energy, which prepared him to either fight the tiger or run away. That heart pounding, fast breathing sensation is the adrenaline; as well as a boost of energy, it enables us to focus our attention so we can quickly respond to the situation.

In the modern world, the ‘fight or flight’ mode can still help us survive dangerous situations, such as reacting swiftly to a person running in front of our car by slamming on the brakes.

The challenge is when our body goes into a state of stress in inappropriate situations. When blood flow is going only to the most important muscles needed to fight or flee, brain function is minimised. This can lead to an inability to ‘think straight’; a state that is a great hindrance in both our work and home lives. If we are kept in a state of stress for long periods, it can be detrimental to our health.  The results of having elevated cortisol levels can be an increase in sugar and blood pressure levels, and a decrease in libido.

FIGHT

When your body goes into a state of stress, we may feel agitated and aggressive towards others; this can be due to our bodies’ natural reaction being “fight”. This can be a helpful reaction to ward off predators, but in unnecessary situations, it can negatively affect relationships and ruin reputations

FLIGHT

Some of us avoid our stressors, removing ourselves from the situation instead of tackling it. This can be a sign of the “flight” survival instinct; a function that can save our lives if we find ourselves in dangerous surroundings. However, in everyday life, this natural instinct can lead to a stressful situation escalating, and increase our stress levels when we realise that the stressor isn’t going away and we need to face it

FREEZE

Unknown by many, there is a third mode that stress can cause; freeze. For some people, becoming stressed sets the stage for ‘dysregulation’. The energy mobilized by the perceived threat gets “locked” into the nervous system and we ‘freeze’. This  response sometimes reveals itself when we breathe. Holding our breath and shallow breathing are both forms of freeze. The occasional deep sigh is the nervous system catching up on its oxygen intake.

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Resilience | How stress affects your body and brain

What does it really mean when we talk about stress? Clinical Physiologist Lead, Marcus Herbert, explains what's going on inside your body and your brain when stress strikes.

Stress is a very personal matter, in that it relies on our own perceptions. Put simply, stress is when a situation, pressure or change exceeds our coping abilities.

Take a rollercoaster ride for example. You might have two people that go on a rollercoaster together - one person may take genuine enjoyment from the experience. The other may experience genuine fear or anxiety. The rollercoaster itself doesn't change but our perceptions of it will differ. The same can be said for other stressful situations.

Of course, this example is just short-term stress, which in isolation may not cause us any harm at all. It's only when stress accumulates and exceeds our coping ability without adequate recovery that it becomes a problem. Stress is likely to occur after a build-up of life-change events that can be either positive or negative. They could include a business realignment, a promotion or even something enjoyable such as a holiday. What matters is that there is a change to you normal routine.

We all know that stress can make us feel overwhelmed, agitated and sometimes overwhelmed. The question is how does stress affect our body and our mind, and what can we do about it?

The physiological effects of stress

Within your central nervous system (your brain and spine) you have the autonomic system. This controls all of the processes that you do without thinking, such as breathing, digestion and your heart beat.

Within the autonomic system there are two systems of interest, which work in tandem with each other. These are the sympathetic system, known as the ‘fight or flight’ system, and the parasympathetic system, or the ‘rest and digest’ system.

The sympathetic system is responsible for increasing heart rate, increasing blood pressure and increasing blood sugar to help you to perform when stress hits. When you are stressed, this system triggers these necessary responses, and the function of your rest and digest system is reduced. The parasympathetic system is responsible for suppressing heart rate and bringing you back down to homeostasis.

Another hormone released when we are stressed is cortisol. Cortisol is an energising hormone which increases the level of blood sugar. This is great in the short term to provide energy to react quickly, but in the long term it can be bad for the immune system (as DHEA, which is also released by the adrenal glands and supports our immune system, can’t be released when cortisol is released).

Excess release of cortisol over a long period of time can also lead to increased risk of strokes and heart attacks. When blood sugar levels are raised it can lead to inflammation of artery walls. This damage can cause the immune system to respond, leading to a build-up of fatty deposits which can block the arteries. If some of this build up breaks away and is released into the bloodstream then it can block smaller arteries that lead into your brain or heart.

Stress can also limit our ability to think clearly. When we are stressed our ‘amygdala’ labels information coming into the brain as threatening and at the same time, limits activity in the cerebral cortex, the part of our brain that allows us to think strategically. This reduces our ability to make decisions, be sociable and take on new ideas and information. As a result, you may act in a way that you might later regret.

Coping strategies

So how can we combat these effects of stress and learn to develop resilience and perform better under pressure? When it comes to effective stress management, it's important to focus on the factors that are within your control.

1. Better sleep

Getting a good night’s sleep is important in reducing stress because when we are deprived of sleep, the amygdala becomes much more reactive and so will our minds and bodies. It’s also important to take regular breaks during the day to re-energise.

2. Gentle exercise

Low to moderate intensity exercise with a focus on muscle activation and breathing, like yoga can also have a positive effect on stress. That’s because it drives up the activation of the rest and digest system, rather than the fight or flight system which is activated during more intense exercise. Therefore, going for a gentle walk before bedtime can be more beneficial than a high intensity run. Furthermore, exercise can be a welcome distraction from the stressors in your life.

3. Don't look to substances to unwind

There are some lifestyle considerations that can help reduce stress too. Ingesting caffeine, alcohol and nicotine all increase the activation of the fight or flight system. So smoking and drinking wine are not the destressors that people think they are.

Taking these factors on board and modifying your behaviour can help you to improve your ability to prepare for, react to and recover from the stressors in your life, ultimately improving your resilience.

Author: Marcus HERBERT, Nuffield Health Clinical Lead Physiologist in the South East

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