What do you think of when you hear the word “stress”? I guess that many of us first think of how we might respond to the many demands and pressures of modern life. Our 21st century world often seems full of deadlines, targets, comparisons, pressure to be “on call” all the time and unrealistic expectations to be able to achieve in all areas of life. It’s no wonder that so many of the clients I see in clinic report high levels of stress. This is chronic emotional stress, the type that results from the car breaking down when we’re rushing to get to a job interview, the worry about the health of a loved one or concerns over where the next mortgage payment is coming from.
However, have you ever stopped to consider that this is not the only type of stress to which our bodies are subjected? In this article, I want to introduce the concept of a total stress load, made up of both mental, emotional and physical stress. Most of the time we don’t consider that physical stressors can have a similar effect on the body as emotional stressors, but they definitely can! I’ll explain the effects that any type of stress has on the body and hopefully give you some food for thought as to how to reduce your overall stress load.
Human evolution and the stress response
For most of history, humans have been hunter-gatherers, and we have evolved to cope well with the kinds of 
situations in which hunter-gatherers frequently found themselves. Modernisation of our lifestyle has occurred only relatively recently in our human history. For example, it’s only since the Industrial Revolution that we stopped living our lives in accordance with the rhythms of sunrise and sunset and started planning our days according to the demands of clocks. Because biological evolution happens at a very slow pace relative to the pace of modern technological advances, our bodies are better adapted to live as hunter-gatherers than in 21st century society! Let’s consider, then, the human stress response in the context of stresses that a hunter-gatherer might have been exposed to.
Hunter-gatherers probably weren’t exposed to the same sorts of ongoing stresses as we are today. They would certainly have needed to be able to respond very quickly and effectively to acute dangers, such as being chased by a predator. In such a situation, they would have needed instant energy to be able to run away, oxygen to be delivered to their muscles to run and sharp vision to see where they were going. Then they would either escape or be eaten and the stressful time would be over. They would then have a quieter time spent socialising, eating and drinking, and sleeping. It is perhaps to equip humans for such an event that we evolved 2 branches of our autonomic nervous system. These are called the sympathetic and parasympathetic responses, but they are more commonly called “fight or flight” and “rest and digest”. Let’s take a look at each of these in turn.
We activate the fight or flight response when danger is perceived. In hunter-gatherer times this could have been when a predator was spotted, but nowadays we are more likely to activate this response due to a longer lasting, chronic stress such as a work or financial pressure. In fight or flight, our pupils dilate so that we can see where we’re running to. The brain releases adrenaline and noradrenaline, making our heart beat faster, raising our blood pressure and dilating the bronchi in the lungs so that we can supply more oxygen to our muscles. We begin breaking down our body’s carbohydrate stores (called glycogen), turning them into glucose to fuel the physical effort of running away. During the emergency situation of fight or flight, the body will not waste any of its precious resources on digestion or immunity, so blood flow to the digestive system is reduced and immune function is impaired. This all makes sense when running away from a predator, doesn’t it? However, it doesn’t really make so much sense if our stress is due to having to study for exams or write a report by 3pm on Friday – we don’t physically run away from these problems, using all the glucose that has been released into the bloodstream, and unfortunately these types of stresses do not resolve so quickly.
By contrast, when the rest and digest response is activated, saliva and digestive juices are stimulated and the body has resources to devote to immunity and repair.
Note that both these responses are healthy evolutionary adaptations to the demands of life. What has changed in our modern world is that we spend much longer in the fight or flight response than we evolved to, and much less time in the rest and digest response.
Chronic stress today
Much of the stress that we experience is chronic; it does not resolve quickly but keeps going. This means that we spend much of our time in the fight or flight response. The physiological consequences of this can be:
- High blood sugar, contributing to the epidemic of prediabetes and diabetes (1)
- High blood pressure, leading to a higher risk of cardiovascular disease
- Low or dysregulated immunity, leading to frequent illness and autoimmune disease(2)
- Impaired digestion, often leading to bloating and discomfort
- Disrupted circadian rhythm, leading to tiredness and insomnia
- Imbalanced sex hormones – the body sees reproduction as a low priority for resources in times when it is threatened – leading to menstrual problems and difficult transitions through menopause for women and potentially infertility in men (3).
In fact, the impact of stress on the body is so far-reaching that it is difficult to think of a chronic disease which is not associated with stress. I’m sure that many of you reading this can identify with having had a period of intense emotional stress which was followed by the onset of illness. Robert M. Sapolsky’s book ‘Why Zebras Don’t Get Ulcers’(4) is an excellent read to understand this subject better.
Allostatic load
You are probably all too aware of the mental and emotional stresses in your life. What I want to draw your attention to is the fact that physical factors can activate the stress response in the same way. The body responds to several physical situations as emergencies, initiating the same cascade of neurotransmitters and hormones as if there was an emotional stress. Conditions which invoke the stress response include:
- Large fluctuations in blood sugar (hypo- and hyperglycaemia)
- Infections
- The presence of toxins
- Caffeine
- Obesity
- Extreme heat or cold
- Both too little and too much exercise
You can think of your ability to cope with stress in terms of a bucket. Mental, emotional and physical stresses each 
contribute to the water in the bucket. Taken individually, our body may be able to adapt to each stress. However, the effects are cumulative, and when faced with many different stressors the body may not be able to adapt. This is when ill health can result (the bucket overflows). Means of dealing healthily with stress – spending time in nature, talking with friends, doing activities we enjoy, meditating, practising yoga etc – open a tap on the bucket to release the water safely.
If we keep this knowledge in mind, it becomes easier for us to support ourselves in times of difficulty. If you are going through a stressful time, say facing redundancy, it would not be a good time to train for a marathon, because the combined stress might push your body too far. We cannot always be in control of the physical stresses we experience, but if there is a sudden heatwave AND we are suffering from hay fever, we can be aware that our body is under stress and deliberately take more time out for relaxation or meditation.
Nutrition to support times of stress
It’s not just the activities and relaxation practices that we do that can help us to cope with stress. The food that we eat can have a huge influence on the physical stresses going on in the body, and can also support the health of our brain and adrenal glands which regulate our stress response.
To minimise physical stressors:
- Keep your blood sugar stable
- Avoid toxins in your food and in the environment
- Avoid foods to which you are intolerant
- Drink caffeine in moderate amounts only
- Maintain a healthy body weight
- Eat an anti-inflammatory diet
Making sure your diet is rich in potassium, magnesium, vitamin C, B vitamins and omega 3 fatty acids can also support the health of your stress response system.
These are all cornerstones of the personalised nutrition plans that I develop with each client. By understanding you and your health history, I can come to a judgement as to which of these elements is most out of balance in your life at the moment, and therefore which we might pay most attention to in order to have the most impact on your stress load.
Nutritional therapy may not be the first thing you think of during a time of stress, but nurturing and supporting your body may be what it takes to avoid stress-induced illness.
References
- Joseph, J.J. and Golden, S.H. (2017). ‘Cortisol dysregulation: the bidirectional link between stress, depression, and type 2 diabetes mellitus’, Annals of the New York Academy of Sciences, 1391(1), 20-34. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5334212/ (Accessed 10 July 2019).
- Sharif, K., Watad, A., Coplan, L. et al. (2018). ‘The role of stress in the mosaic of autoimmunity: An overlooked association’, Autoimmunity Reviews, 17(10), pp967-983. Available at https://www.ncbi.nlm.nih.gov/pubmed/30118900 (Accessed 10 July 2019).
- Janevic, T., Kahn, L.G., Landsbergis, P. et al. (2014). ‘Effects of work and life stress on semen quality’, Fertility and Sterility 102(2), p530-538. Available at https://www.fertstert.org/article/S0015-0282(14)00381-1/pdf (Accessed 10 July 2019).
- Sapolsky, R.M. (2004). ‘Why Zebras Don’t Get Ulcers’. New York: Holt Paperbacks.