Whenever I hear people talking about sleep, I think of my own mother, who – so it seemed to me as a child – appeared to ‘prescribe’ it for almost every ailment and eventuality in life. “What you need” she would say, “is a good glass of milk and bed.” “Sleep is the best medicine when you’ re that way out”. The…”that way out” incidentally, might be referring to some minor complaint such as a headache, or a sore limb; or then again it might be just a tendency to be, as she perceived it, irritable or argumentative and difficult to manage.
It has always amazed me that in the business of helping people to cope with stressful and demanding circumstances of life, we pay so little attention to the duration and quality of night sleep. I have attended and participated in many psychosocial oncology meetings and psychosocial stress gatherings and the like, halfway round the globe over the years and have yet to witness so much as a paper (much less session) devoted to the topic of night sleep. Well, we did not make that mistake in my clinics and I do not intend to make it in this correspondence in the form of my blogs.
Sleep is a topic, which has fascinated and puzzled man from his earliest times onward; and it is as vital to our continuing well being as is good food, fresh air, sunshine and exercise. When deprived of sleep, the health of any organism – be it animal or human – is adversely affected. Mood and behaviour may be grossly impaired. Indeed, many patients have told me that among the earliest of adverse changes to be experienced upon the reception of the “bad news” of a diagnosis of malignancy, has been interference with and impairment of an established pattern of regular and refreshing night sleep. “Sleep disorder” may well be just one of a number of symptoms in several psychiatric/psychosocial, behavioural and physical illnesses. However, the loss or lack of sleep does unquestionably weigh disproportionately heavier with us than do many other symptoms. This is not just because of its fundamental necessity but because it signifies interruption of and interference with what we have quickly come to perceive as a natural and essential rhythm in life, from cradle to grave.
The word “sleep” is, as you will probably know, of German origin. It derives from the Gothic “sleps” and is also related to the modern German word “schlaf and “schlafen”, i.e. to sleep. The adjective “schlapp” (literally meaning limp and slack) is similarly derived. The English word “drowsy”, which is associated with sleep, is thought to derive from the old English word “drusian”, i.e. to slow down and sink. Thus a familiar picture begins readily to form in the mind of a ‘slackening and loosening off’ of tension and of unwinding in the form of relaxing and drifting – lazily one might even say – into sleep. Although the history of man (derived from whatever clime and culture) is ‘littered’ with references to and explanations for sleep, it was not until the late 19th/early 20th centuries that such hypotheses about it began to emerge in scientific form. Not surprisingly – and in keeping with the burgeoning growth in the natural sciences – such tentative references were based almost solely on the principles of physiology and chemistry. They included lack of blood to the brain’s cortex, lack of oxygen to the brain, shifts in electrical charges and nerve cell irregularities.
In 1935 a paper appeared in the journal “Science” referring to a finding in sleep of “trains of waves which cannot be correlated with any detectable external stimulus…” It did in fact bear reference – at least in part – to work carried out in Germany more than a decade earlier and independently, by a German scientist and a Russian emigrant. Between them (and other colleagues) they discovered the presence of electrical waves, as measured by an electroencephalograph (EEG) in relaxed but alert subjects of approximately 10 cycles per second. This they named Alpha rhythm. Larger, slower waves evident at times (but only in sleep) were styled Delta waves (less than 4 cps). The “at times” of the previous sentence happens to be important and significant to the staging of what hopefully, you and I (and other human beings on the planet) experience regularly, i.e. sleep. Stage 1 sleep refers to the act of “falling asleep” i.e. that transitional period between waking and sleeping. In those moments, the regular alpha rhythm evident in the relaxed waking state is replaced by flatter and more rapid oscillations. Stage 2 sleep is characterized by larger, slower waves but still regularly interspersed with bursts of the more rapid smaller rhythms.
Once Delta waves have been present for between 25-50% of the time, stage 3 sleep is assumed to be present and stage 4 sleep requires that the presence of the largest, slower Delta waves are now in evidence for at least 50% of the sleeping time. In studying sleep in individual subjects, scientists do in fact commonly apply three separate methods of measurement. In the first place, the electroencephalograph (EEG) is introduced, to measure brainwaves via electrodes strategically placed on the scalp. Next, an electrooculograph (EOG) is deployed. This senses and indicates movement via electrodes positioned near the eyes. Thirdly, readings are taken from an electromyograph (EMG), which charts muscle tension, commonly from electrodes positioned either side of the point of the chin. The type of electrode used is quite tiny, with long, loose, fine wires commonly leading to a panel set into the bed head. Most subjects appear to accept and adapt readily to such new and unaccustomed surroundings. Once the subject is settled for the night, the pens of the polygraphs go into action and recording begins. The EEG will show the typical alpha rhythm at this point, because the subject is still awake although quite relaxed. Most probably the EOG will indicate regular movement of the eyes and the EMG, some muscle tension from around the chin area.
Once in sleep, the subject discharges somewhat larger, i.e. theta waves (4-8 cps) interspersed by more rapid bursts and the occasional appearance of deeper and slower waves. The eyes are still and muscle tension is yet further reduced. Thus, stage 2 is achieved and sleep in this stage is known for many people to take up to half and even more of the total time spent sleeping. Typically, stages 3 and 4 (theta and delta waves) as described earlier, will be achieved, followed by several seconds of major disturbance as the subject changes his/her sleeping position. This will likely be followed by more stage 2 sleep,