Stress: Modern Lifestyle Factors in Opposition to Human Evolution

Can Paleo Improve Low Mood & Depression? | The Paleo DietThe majority of people visiting this website likely do so because they live in a technologically advanced western society that allows and encourages them to own a computer, smart phone, or other internet compatible device. In an era of what seems like limitless technological growth and information access, it can be difficult to slow down and consider that many of the present-day cultural and technological attributes of modern western society are a very recent phenomenon and were unheard of for the majority of human evolution.

Rapid technological advancement and the demand for a faster paced lifestyle within our society has manifested stressors that our bodies are unfamiliar with. Put simply, “Our Stone Age brains just weren’t designed to handle the sedentary, isolated, indoor, sleep-deprived, fast-food laden, stressed-out pace of 21st-century life”.1

There are few studies on psychiatric disorders and stress among modern hunter-gatherers. However, an indigenous population known as the Kaluli of the highlands of Papua New Guinea follows a diet and lifestyle that is comparable to that of hunter-gatherer populations.2 Their population was observed to be virtually free of most of the common mental illnesses afflicting modern western society.3 Perhaps research on stress and mental health in hunter-gatherer groups is limited because it is so rare in the first place.

So, what exactly is to blame for the rapid rise of stress-induced mental pathologies in modern western society? Not every factor can be listed due to the vast array of stress inducing variables in western society, but here are a four factors in that are in strong opposition to our pre-agricultural hunter-gatherer way of life:

Diet

The food you eat is the foundation of any success you’ll experience in improving your overall physical and mental well-being. Most westerners follow an inflammatory diet far removed from our evolutionary past that is centered on the consumption of grains, omega-6-rich foods, artificial sweeteners, dairy, and other low-nutrient density foods.

This is a sure recipe for disaster for those seeking mental clarity.  Instead focus on eating an anti-inflammatory ancestrally-based Paleo diet that includes pasture-raised non-dairy animal products, fresh fruits and vegetables, nuts, seeds, and either animal tallow, olive oil, or coconut oil for cooking.

One of the best nutrients you can consume on a regular basis for superb mental health is a PUFA (polyunsaturated fatty acid) known as omega-3 fatty acid. The fact alone that one out of every three fatty acids in the human central nervous system is comprised of PUFA should be enough to convince you how important omega-3 fatty acids are for your brain’s health.4 Furthermore, cross-cultural studies on rates of depression5, bipolar disorder6, and seasonal affective disorder7 were demonstrated to be lowest in countries consuming diets rich in omega-3 fatty acids from seafood. Omega-3 fatty acids are also critical in the production of the mood and motivation associated brain neurotransmitters serotonin and dopamine.1 Salmon, mackerel, sardines, oysters, cod, herring, shrimp and wild or pasture raised meat and eggs are all great sources of omega-3 fatty acids.

Isolation

In a world that is more “connected” digitally than ever before, we are ironically seeing more and more people alienated and socially isolated than ever before.1 As social internet networks and other forms of digital communication begin to become more prevalent in western society, the opportunity and desire for actual face-to-face social events become less necessary. More and more people are choosing to spend time communicating virtually in the form of text, email, and online chatting instead of in real life as we have for the majority of our evolution. Even in social situations that normally encourage present-mindedness and genuine communication, many will choose to isolate themselves in the virtual reality contained within their smart phones, thus further degrading the natural flow of human sociability.

Believe it or not, isolation was a very rare occurrence in hunter-gatherer societies and typically only happened temporarily during spiritual quests or if a member of a group was separated or lost. A hunter-gatherer group’s survival depended on the group’s ability to communicate strategies and ideas in an effective and deliberate manner.

Imagine the stress of trying to plan and carry out a hunt as a hunter-gatherer while everyone in your group is intermittently trying to check and respond to the ever changing and isolation imposing demands of a smart phone. Your ability to be attentive and present minded would be heavily compromised. It simply wouldn’t work. We were designed not for endless hours of isolated screen time, but rather for constant face-to-face social interaction. It doesn’t take science to understand how real social situations put you in a good mood and eases stress. It’s intrinsic to human nature.

Sedentary Lifestyle

A sedentary lifestyle tends to go hand-in-hand with isolation. More screen time usually means more time on the couch or office chair. Frequent exercise and taking up an occupation that does not require long periods of sitting are ideal for combating this issue. It is widely known that exercising causes the brain to release endogenous opioids known as endorphins which can be helpful in alleviating stress-related disorders such as anxiety and depression.8 Conversely, too much exercise can have negative effects on mental well-being.9 Seeking balance is key.

Circadian Rhythm

Circadian rhythms are an often-undervalued component of good health that is largely ignored in modern society.  Put simply, your circadian rhythm is all the physiological processes that happen within your body in a span of 24 hours.10 Your body’s circadian rhythm is dictated by factors such as sunlight and temperature.

The sun’s influence alone causes the body to produce both the stress hormone cortisol and the sleep hormone melatonin to maintain equilibrium in bodily functions throughout the different seasons. In the summer, cortisol is high and melatonin is low. In the winter, the inverse is observed.11

Modern technology now allows for light 24/7 regardless of the season or time of day in just about every person’s home. Instead of having higher levels of melatonin flood our brains upon nightfall, the abundance of indoor lighting effectively suppresses melatonin and tricks our brains into thinking that it is still day time well after the sun has set. Blue light is particularly effective at suppressing melatonin and the highest emissions are from computer displays and televisions.

The end result is high levels of the stress hormone cortisol circulating through one’s body constantly. Year-round suppression of melatonin and heightened cortisol can contribute to chronic stress, inflammation, and mental health issues related to sleep deprivation that can go on endlessly.12

It’s worth noting that blue light is not inherently bad and is actually needed during the daytime to ensure alertness, productivity, and adequate Vitamin D3 (very important) uptake. It’s when blue light is delivered in the evening and late night hours that it becomes problematic.13 After sunset it’s best to avoid late night television binges or close contact with computer screens to avoid high cortisol upon hitting the sack for the night. There are plenty of other activities such as reading a book, listening to music, socializing, meditation, etc. that do not entail exposure to blue light. Choose light bulbs for your house that are rated at 2700 degrees Kelvin or less. Also, consider installing “f.lux” for your home computer to lessen the blue light exposure coming from your computer screen if you must use your computer into the night.

Final Note

It’s wrong to think that hunter-gatherers lived a completely stress-free life. Stress is a necessary for natural selection pressures and is likely what guided the selective forces that shaped humankind. But the type of stress that hunter-gatherers underwent was likely a very different kind of stress than what is observed in modern society. It was almost certainly not the constant unrelenting stress emphasizing ruminating thoughts and constant preoccupation or worry that is so prevalent in western society. Instead, stress and the release of cortisol was likely an episodic response to periodic events such as food shortages, predators, and confrontation with neighboring clans.

Nowadays, the innate complexity of modern society tends to create a psychological functioning that lends towards chronic low-grade stress as an adaptation mechanism to deal with the ever-increasing multifaceted demands of western existence.14

It is next to impossible to completely emulate the lifestyle of a hunter-gatherer if you are a citizen of western society as a solution to stress and overall health. That being said, you can certainly question many of the cultural attributes that are taken for granted in modern life in relation to our hunter-gatherer past and seek solutions that fit your personal circumstances. Building a lifestyle that is centered upon healthy eating and emphasizes stress relief instead of chronic stress is essential for keeping inflammation low and mortality high.

References

[1] Ilardi, S. S. (2009). The depression cure: The 6-step program to beat depression without drugs. Cambridge, MA: Da Capo Lifelong.

[2] Feld, Steven (1982). Sound and Sentiment: Birds, Weeping, Poetics, and Song in Kaluli Expression. Philadelphia: University of Pennsylvania Press. pp. 4–5.

[3] McErlean, B. (2015). Soundness in mind and body. Veterinary Record177(23), i-ii.

[4] Logan, A. C. (2004). Omega-3 fatty acids and major depression: a primer for the mental health professional. Lipids in health and disease3(1), 1.

[5] Hibbeln, J. R. (2002). Seafood consumption, the DHA content of mothers’ milk and prevalence rates of postpartum depression: a cross-national, ecological analysis. Journal of affective disorders69(1), 15-29.

[6] Noaghiul, S., & Hibbeln, J. R. (2003). Cross-national comparisons of seafood consumption and rates of bipolar disorders. American Journal of Psychiatry160(12), 2222-2227.

[7] Cott, J., & Hibbeln, J. R. (2001). Lack of seasonal mood change in Icelanders. American Journal of Psychiatry158(2), 328-328.

[8] Peluso, M. A. M., & Andrade, L. H. S. G. D. (2005). Physical activity and mental health: the association between exercise and mood. Clinics60(1), 61-70.

[9] Pierce, E. F. (1994). Exercise dependence syndrome in runners. Sports Medicine18(3), 149-155.

[10] Purves D, Augustine GJ, Fitzpatrick D, et al., editors. Neuroscience. 2nd edition. Sunderland (MA): Sinauer Associates; 2001. The Circadian Cycle of Sleep and Wakefulness. Available from: https://www.ncbi.nlm.nih.gov/books/NBK10839/

[11] Wiley, T. S., & Formby, B. (2000). Lights out: Sleep, sugar, and survival. New York: Pocket Books.

[12] Quera Salva, M., Hartley, S., Barbot, F., C Alvarez, J., Lofaso, F., & Guilleminault, C. (2011). Circadian rhythms, melatonin and depression. Current pharmaceutical design17(15), 1459-1470.

[13] Münch, M., Linhart, F., Borisuit, A., Jaeggi, S. M., & Scartezzini, J. L. (2012). Effects of prior light exposure on early evening performance, subjective sleepiness, and hormonal secretion. Behavioral neuroscience126(1), 196.

[14] Sapolsky, R. M. (1994). Why zebras don’t get ulcers: A guide to stress, stress related diseases, and coping. New York: W.H. Freeman.

About Kyle Cordain, B.A.

Kyle Cordain, B.A.Kyle Cordain is a recent graduate (B.A.) of Colorado State University with a major in Anthropology and a minor in Global Environmental Sustainability. His research focus has emphasized past and present
indigenous peoples, human ecology, and archaeology.

Kyle is a native to Colorado and enjoys many outdoor activities including skiing, hiking, fishing, and camping. In his free time he prefers to play guitar and listen to music.

Comments to this website are moderated by our editorial board. For approval, comments need to be relevant to the article and free of profanities and personal attacks. We encourage cordial debates for the betterment of understanding and discovery. Comments that advertise or promote a business will also not be approved, however, links to relevant blog posts that follow the aforementioned criteria will be allowed. Thank you.

“2” Comments

  1. I agree pretty much with everything stated in the article but wanted to make some further points mainly around homeostasis – our minds have the capacity to reduce stress, tension and anxiety without stopping leading an active busy life. But, first some background.

    Hans Selye was an extremely clever man, spoke several languages amd was still learning English when he had to invent a name for his subject matter. It is said that later in his life he told people that if he understood English better then he would be known as the father of strain rather than the father of stress.
    In engineering, stress is force applied and strain is the resultant deformation. Using clearer nomenclature, the dose makes the response. The stress is the external force or pressure applied eg job insecurity, relationship insecurity, bad health etc. tHowever, it is not these external factors cause the dose. The dose is actually the internal disturbance (anxiety and tension generated) resulting and the response may be adverse effects on behaviour, mental or physical health. Take a group of people and put them under fairly serious stress. Some will be unaffected, some will bend uncomfortably a bit. A few will break with over symptoms of anxiety,tension and psychosomatic disease. The difference is in coping (a homeostatic process).
    So, what is anxiety? Using a very simple, analogy if the incoming nerve signals exceed our ability to integrate them then we experience this as anxiety. As our brains have become more sophisticated and sensitive we have become more susceptible to it.
    In a way, anxiety is a sort of general warning signal. You can imagine in primitive times as the environment changed and a situation started to become more hazardous there would be more sensory input. There might also be more internal input from physical activity. Also, when overt danger occurred then the body really geared up with that overt sympathetic response as part of the famous fight\ flight response to try and avoid iminent injury or death. However, after the dangerous situation was resolved, assuming survival, then there was a slowing down. A rebalancing of the sympathetic and parasympathetic systems and a reduction in nervous activity.
    In addition, groups of hunter gatherers tend to nonverbally communicate a sense of calm to each other when safety occurs and very rapidly of tension when danger occurs. Today we still see this in the behaviour of the unruly mob. The calm of the crowd is sadly less common but can sometimes pervade religious\spiritual activity, meditation classes or a small group in wonder of nature etc.
    Practically every aspect of our being as human animals is governed by homeostasis. Should not the level of anxiety be governed by such a homeostatic mechanism? I believe that it is. But, that in modern western society “natural mental rest” is not being learnt or circumstances mean it does not spontaneously occur eg
    ⦁ the routinisation of work since the industrial revolution tends to prevent short spontaneous mental ,
    ⦁ indeed many people have time management and are concerned about unproductive wasted time. Truly ironic if you believe as I do that we must spent some time awake just being in a state of mental rest. Of course, if we are well rested our creativity and productivity is substantially increased.
    ⦁ the breakdown of the extended family means that people do not learn natural mental rest as part of the socialisation that would occur in the extended family or hunter gatherer group situation,
    ⦁ the increased potential sensory input from the digital age creates a large amount of nervous activity that must be integrated and can prevent short spontaneous mental breaks breaks as people are increasingly spending every waking moment in activity with little or no time spent in repose.
    ⦁ reductions in other factors like nutrition, exercise, sleep, sensible sunlight exposure such as you have outlined in the article.

    Before consciousness there was unconsciousness. Going back in evolution there was a time that primitive organisms were not conscious. Then the “new” state of consciousness emerged. Like any newly evolved state it was unstable and there was a periodic need to return to the simpler state to permit rest. Mammals still have a need to return to unconsciousness – we call that state sleep.
    At an earlier stage of our evolution our primitive hominid ancestors did not possess the complex critical thinking that modern humans are capable of. They communicated very simply using gesture, behavior, grunts and noise etc. A bit like the dog who looks at you wags his tail and moves towards the door. The dog is saying you like me you must come to the door. If you follow the dog you will work out what it is the dog is asking for. Yet the dog has not spoken a single word. Undoubtedly our hominid ancestors were more sophisticated than dogs but their communication was simpler than the use of complex language is today.
    Many people can recall being awake and having an experience of reverie or day dreaming (no dreams really) where the mind went blank, thoughts slowed or ceased and that this was a pleasant or even quite profound experience. Of course, this is only realised afterwards – you cant be thinking my mind is still – the thought means it is not. In these moments or minutes the mind is returning to a simpler mental state. This is a natural mental rest and it permits the homeostatic mechanism to integrate all the nervous system input. A secondary effect of high anxiety is the development of patterns to reduce the anxiety such as avoidance of situations. If anxiety is reduced but continuing the avoidance analogy the potential benefits of being in that situation are never realised. The situation could be the small talk of socialising, relating to the opposite sex, being alone etc etc. So it is also important to note that the return to this simple state repeatedly over time and the effects of natural mental rest permit more natural patterns of behavior to develop as anxiety is reduced. Everyone has some anxiety but each of us may be able to experience less of it if we allow ourselves to experience this natural mental rest..
    Much of what I have said here is already in the published peer reviewed literature. The eminent psychiatrist Dr Ainslie Meares published many of these ideas in his 30+ books and 150+ articles – including 9 in The Lancet. He developed a new theory of hypnosis in the 1950s, widely acclaimed at the time, which saw his colleagues elect him for a term as President of the International Society of Hypnosis. He travelled extensively doing field research (a bit like Western Price): meeting primitive peoples, yogi’s, sufi’s, witch doctors, voodoo practitioners and others. Out of his theory of hypnosis he developed what he called a relaxing mental exercise which was later published in multi million selling DIY book Relief without Drugs published in 1967. His method is still practiced, mainly in Australia, where we know it as Stillness Meditation. Although it is not really meditation – it is natural mental rest. The other side of the coin was that Meares said that people should not withdraw from an active busy life. Rather they should practice stillness meditation twice a day for 10-15 minutes and let the calm flow on or enter into their daily lives so that over time they learnt to live calmly and at ease.
    Meares made extensive use of meditation for helping people cope better with anxiety affecting behavior and also the body. He expanded his work to include those who simply felt life could be better. Some 60 years later, Ainslie Meares is sometimes remembered as the doctor who first used meditation to help heal cancer. He taught his cancer patients to experience prolonged periods of natural mental rest of sufficient duration to reduce cortisol and in about 1/3 this shifted the balance enough to slow down the growth and in some instances (1 im 10) this resulted in regression. Meares himself died unexpectedly in the mid1980s but some of his cancer patients from the 1970’s are still alive today. The cancer work was important but overshadowed his earlier work – it was seen as heresy by many in the medical profession. Of course, others also found a similar effect and today conventional medical wisdom is that both the body and the mind contribute to cancer and that healing cancer involves several techniques including surgery, cancer cell killing techniques and stress management.
    At one point, Meares went on holidays and one of his cancer patients decided to improve stillness meditation by visualising her immune system killing the cancer cells. She relapsed badly. Meares returned and showed her stillness meditation and she improved and lived for several more years. Meares wrote the case up and also another paper in which he identifies and categorizes the various types of meditation with the main conclusion that it is a reduction in mental activity as thoughts slow and ebb and the mind becomes still that is the important factor in permitting natural mental rest. This is an important point as many human created methods of meditation use thought, sensation and or emotion to a monotone which is a dulling that is not stillness.
    Just as I encourage anyone to explore the Paleo diet and related lifestyle factors I also encourage people to explore stillness meditation. There is a perfect fit. Stillness meditation is paleo meditation. But it is not “meditation”. Meditation is really only a convenient label to describe the natural mental rest our human ancestors also experienced.
    cheers OB

Leave a Reply

Your email address will not be published. Required fields are marked *

Affiliates and Credentials