In his bestseller “Sapiens: A Brief History of Humankind”, Harari wrote:
“Human history was consequently dominated by two main cycles: the growth cycles of plants and the changing cycles of solar energy (day and night, summer and winter). When sunlight was scarce and when wheat fields were still green, humans had little energy. Granaries were empty, tax collectors were idle, soldiers found it difficult to move and fight, and kings tended to keep the peace. When the sun shone brightly and the wheat ripened, peasants harvested the crops and filled the granaries. Tax collectors hurried to take their share. Soldiers flexed their muscles and sharpened their swords. Kings convened councils and planned their next campaign. Everyone was fuelled by solar energy — captured in wheat, rice and potatoes”
We humans needed to live much more aligned with the natural cycles. Nowadays food is available year round by shipping it from the other side of the planet. There’s always work to do because most jobs in developed countries have nothing to do with agriculture. Taxes are collected year-round, etc.
We don’t typically live very aligned with natural cycles or rhythms anymore. This independence of the sun and sunlight (in the sense of being able to switch on a light and work all night long and even install lights to grow tomatoes indoors in winter) are often seen as a great achievement but is that separation from the rest of nature actually good for us?
For this article, I elaborate my thoughts on workload and seasons. I cite Harari above who explains that it was common to be less active in winter and therefore pose the question:
Is it better to reduce workload in winter?
Psychological research has shown that our health improves if we follow the natural rhythms. The most studied rhythm isn’t about the seasons but about day and night and called circadian rhythm. Regarding that, conclusions are very clear: It’s better for our immune system, psychological wellbeing and other health markers to rest at night and come alive during the day.
The circadian rhythm is regulated by light and works in the human body with the hormones melatonin and cortisol. In short, melatonin makes us sleepy and cortisol wakes us up and activates us. Artificial light can disturb the natural circadian rhythm and long-term or repeated disruptions have been shown to contribute to diabetes, depression, breast cancer and a long list of other illnesses (e.g. Gale et al., 2011, Salgado-Delgado et al., 2011, Flipinski, Li & Lévi, 2006). That’s why sleep experts recommend dimmed light and no screens before bedtime as well as waking up with natural light (Law & Maguire, 2016).
This doesn’t answer the question but gives us an indication that it might be important to be aligned with the rhythms of nature. Let’s continue the investigation.
It is challenging to experimentally study the health and wellbeing of humans living seasonally, which might be the reason for little scientific articles on this topic. What has received a lot of scientific attention and can help us answer the question is winter depression. Officially called Winter Seasonal Affective Disorder, it is a diagnosable psychological condition that comes with several symptoms including lack of motivation, loss of interest in being active, low energy, and difficulty concentrating. As the name suggests, it is associated with the winter season and correlates with lower minutes of sunshine, length of daylight as well as decreased temperature (Molin et al., 1996). Harari pointed out that we used to be more idle in winter, which is exactly what winter depression forces the people who experience it to be.
To be fair, even people who do not diagnose as experiencing a winter depression tend to have lower energy levels and a harder time motivating themselves during winter . Perhaps the lack of energy and motivation in winter is a pointer for us to slow down, not something to be fought. Even though we humans don’t typically hibernate like other mammals do, it could actually be helpful to demand less from ourselves in winter.
For now, what I can provide is anecdotal support for slowing down in winter, based on activity levels in other animals, psychological studies of seasonal affective disorder, as well as the evidence that living aligned with other natural rhythms correlates with improved health and wellbeing.
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Harari, Y. N. (2015). Sapiens: A Brief History of Humankind. Harper.
Gale, J. E., Cox, H. I., Qian, J., Block, G. D., Colwell, C. S., & Matveyenko, A. V. (2011). Disruption of circadian rhythms accelerates development of diabetes through pancreatic beta-cell loss and dysfunction. Journal of biological rhythms, 26(5), 423–433.
Salgado-Delgado, R., Tapia Osorio, A., Saderi, N., & Escobar, C. (2011). Disruption of circadian rhythms: a crucial factor in the etiology of depression. Depression research and treatment.
Filipski, E., Li, X. M., & Lévi, F. (2006). Disruption of circadian coordination and malignant growth. Cancer causes & control, 17(4), 509–514.
Law, R. & Maguire, M. (2016). Biological Cycles and Cognition. In Groome, D. & Eysenck, M. W. (Eds). An Introduction to Applied Cognitive Psychology. Psychology Press.
Molin, J., Mellerup, E., Bolwig, T., Scheike, T., & Dam, H. (1996). The influence of climate on development of winter depression. Journal of affective disorders, 37(2–3), 151–155.