“Sleep that knits up the ravelled sleeve of care
The death of each day’s life, sore labour’s bath
Balm of hurt minds, great nature’s second course,
Chief nourisher in life’s feast.”
— William Shakespeare
One of the many curiosities about my time in Solomon Islands over the past years has been the way locals relate to sleep. I have been raised to think of sleep as a necessity obviously, and something done at night when not much else is happening. I have thought of weekends as a chance to alter routines by staying up later, sleeping longer (or “catching up” whatever that means), then by the time monday rolls around, look to more of a routine-esque sleep pattern if I want to keep the work/study/training/social/domestic gig alive. I knew that a lack of sleep made me perform poorly at school, work, the gym etc, but I never really pondered upon how sleep patterns work, and whether or not they are socially, biologically, environmentally or hormonally conditioned.
Solomon Islanders don´t seem to have set routines when it comes to sleep. For that matter, when they eat and are physically active either. It took me some time before I realized that the linear routine of the common Western way of living does not apply to this Melanesian archipelago. Food and sleep and exertion occurs when it occurs. It seemed to me that if I was to survive in rural areas, my body would have to assimilate its natural rhythms to local time as best it could. This meant being hungry, over satiated, so well rested to become stiff, exhausted from random bouts of paddling, trekking, football, bored and over stimulated. In other words, my comfort zones were put to the test every day, by not being able to precisely judge what was about to happen. It was never drastic however. Mostly, locals rested, stayed out of the heat, chatted, chewed betel nut, and left the running about for the kids. I was an anomaly for many reasons, not the least, because I found it hard to rest so much, always on the move for more ethnographic knowledge.
I wondered how Western society has become so agitated, so excuse-orientated, so dissatisfied with its lot?. I know this is a multi-facited dilemma, but the way we look at sleep, and the way Solomon Islanders do, made me search for a deeper understanding of this massive part of our lives.
1. How does lack of sleep affect our physiological/mental/metabolic performance?
2. Is sleep a universal requirement for mankind, or are we quick to adapt to different ´lifestyles´?
3. How does light affect sleep? What about the huge changes in daylight from Northern/Southern hemisphere to equatorial regions?
4. Why am I tired in the winter months, but awake in the summer months? Are we like bears or bats?
Robb Wolf is a guy whose advice seems to resonate on many levels with sensibility and logic. Often talking about the importance of sleep, Wolf advocates getting as much as possible short of getting divorced or fired, and in terms of training, weight control, hormonal balance, cortisol levels and insulin intolerance to name but a few factors, sleep is an obvious component of a healthy lifestyle. But still, I needed to know more about circadian rhythms and environmental factors that have selected us to become tired and awake in different ways at different times of the year. After all, modern man only recently ventured away from equatorial regions out to the extremities, and surely our genetic makeup has allowed for adaptability, but not adaption?. I suspected that sleep was another factor that was being manipulated by modern life, trying to con the physiology of our natural life cycles to fight the need to rest.
I read “Lights Out: Sleep, sugar and survival” by Wiley and Formby (2001) on Robb Wolf’s recommendation. Good read indeed, despite the mediocre reviews. I found their argument about seasonal changes effecting not only our dietary requirements, but our need for more or less sleep relating to light and energy zones very much standard evolutionary theory, but sleep specific, in that we cannot speak of optimal health by preferencing one factor (diet, lifestyle, rest, movement) over the other. In this sense, it strikes accord with a paleo-like way of thinking, if not in a more extreme context. To suggest that summertime (obviously this is a Northern hemisphere bias book) is party-time, stay up late, eat, drink and be merry type gig, viz-a-viz wintertime, where we should hybernate like a bear, and live in darkness is more to highlight our misguided lifestyles, than a doctrine to be strictly abided by. Despite the somewhat sloppy writing style (having just finished Gary Taubes’ excellent Why we get fat: And what to do about it) the message appears clear:
- Sleep more, in order to recover
- Avoid sugar, grains and excessive carbohydrates
- Listen to your body as it is trying to be in tune with the seasons
- Excessive artificial light in winter and sleep deprivation screws your hormonal balance, and exacerbates carb addiction
Lack of sleep blunts human growth hormone response, raises cortisol levels and causes insulin resistance. Not good, unless you want to soften out.
Anthropology, as the great bastion of holistic social sciences, has strangely remained quiet on the issue of sleep. Professor Carol M. Worthman, a leading researcher on the social ecology of sleep and hormone related developmental issues at Emory University, Atlanta, has crucially shown that the majority of clinical research and trials on sleep related disorders and habits are based on Western societies where sleep patterns are drastically different from societies where artificial light sources are infrequently available, and seasonal changes are minimal. The comparative field of evolutionary medicine is one branch of anthropological research that can be useful cross-comparatively in determining the extent of sleep variation in cultures with a focus on certain variables that point to deterioration of physical and mental health. As yet, no long-term cross-cultural epidemiological studies have been carried out that allow us to ascertain the effects of sleep deprivation, and lead us to a better understanding of the ideal way our biological sleep temporality effects our wellbeing, regardless of locality.
A better understanding of the history of sleep practices is needed so the social and physiological constraints that allow sleep to become inextricable linked to circadian patterns of consciousness, which are both phylogenetically and ontogenetically determined, become slightly more demystified. After all, to confuse this matter further, or at least my curiosity as to why Solomon Islanders slept so randomly, is the fact that circadian rhythms, and the hormonal action that takes place regulating our biological makeup, occur whilst awake AND asleep. It has the makings of something sci-fi this sleep thing. We are sleeping less and less, have more and more clutter and stress and fake-food surrounding us, and even try to alter our physical and genetic makeup by synthetic interventions – that perhaps humanity is trying to out-wit biology and attempt not just to stay up late, but stay up forever?.
I recently stumbled upon the work of A. Roger Ekirch, historian, and author of the fascinating “At Day´s close: Night in Times Past” (2005). Taking us back to the medieval days of the 16th-18th centuries, before the advent of electric lighting, Ekirch reveals the common segmented sleep patterns broken up into “first sleep” (dead sleep) and “second sleep” (morning sleep) and all the interesting nocturnal events that went on in between. Lights, he reveals, eliminated this pattern of semi-consciousness, where people would often have sex, pray and reflect. For me this is a startling find, and made me think of the way Solomon Islanders seemed half-awake, but never fully able to function in full consciousness. Often I would hear conversations, when all appeared quiet. Biphasic sleepers?.
Maybe, by looking back at our polyphasic sleep patterns from an historical perspective, comparing that with our monophasic tendencies nowadays, we are denying our evolutionary part in the animal spectrum once again?. An interesting article on biphasic sleep written by psychiatrist Thomas A. Wehr on a study about photoperiodicity (circadian rhythms) seems to confirm our tendencies to sleep in 2 periods (biphasic) of roughly 8 hours, but that artificial lighting and social norms have made us monophasic sleepers, which is not in accordance to our natural biology. To really start to geek-out on this, try this PubMed article on the evidence for a biological dawn. I also found paleohacks a goldmine of information on this issue, and as a bonus, stumbled upon this great thread for sleep hacking. Must give Tim Ferris a big High5 for getting me inspired.
I feel the need to do some more research though, and self-experimentation. Maybe my biological clock will tell me when it is time for that. I trust that clock, for it has made us a perfect species for adaptability to so much modern life presents to us, but we need sleep, and a good deal more than we are getting. That we cannot deny.