Human beings have been known to display rhythmic cycles relating to basic physiological functions, mental agility, moods and emotion. These natural control systems of the body are known to follow the circadian cycle which means “about a day” in Latin. This rhythm in turn is correlated with the period of darkness and daylight hours each day. It therefore implies that all our body functions, like intake of meals at regular intervals, sleep pattern mainly at night, mental sharpness and physical efficiency are directly related to the sunlight which in turn controls the body clock. The body clock acts as the guardian of all rhythms, which when disrupted creates the need to retune the clock artificially.
According to an emerging science known as chronobiology when the circadian rhythms are disrupted many body functions are thrown out of gear. An individual, interestingly, is aware of his local time by regularly eating meals at prescribed times. Very often even without looking at the clock, the body transmits the message of hunger if any meal is overdue. This steady rhythm of eat-work-sleep in relation to daylight/ darkness if disrupted can reduce the overall efficiency of the human body.
While normal human beings following a steady lifestyle and exposed to the path of the sun seldom deviate from their schedules, travellers are the most affected. The mode of travel like road vehicle, rail or ship being inherently slow as also subjected to diurnal rhythms of the sun does not induce a change in the bodily functions as the body clock is subject to a very gradual change with the reassuring sun always remaining visible. Whereas, if travelling by air across various time zones, the human body fails to adapt itself to the local time of the destination, thereby, causing the body to feel unduly tired. This effect is popularly known as “Jetlag”. The body takes a couple of days to re-orient its internal clock to the new daylight/ darkness pattern in that particular time zone.
Mariners from time immemorial have been adjusting their clocks both mechanical and biological on crossing time zones or the international dateline by either advancing or retarding their watches but very gradually as time zones are generally adjusted once a day during voyages on the surface of the sea. Therefore, the marine human body is able to readjust itself easily through sheer repetitive practise. With the advent of various fighting machines, the deadliest of them being submarines, for fulfilling mankind’s quest for power, a special breed of man is required to run these formidable machines. This set of people willingly lock themselves up in sharks of steel and travel inside the deep seas like predators stealthily waiting to pounce on their prey. This daring lot is subject to the most vicious disruption of the chronobiologic rhythm and their body clocks have to be given frequent false images so as to be able to run them in tune always.
Life on a submarine is bereft of the luxury of being able to see the sun. With artificial lighting switched on all the time inside the submarine, the body clock very quickly loses its bearings and results in making this daring lot, a bunch of dull, bleary eyed, constipated men suffering from loss of appetite. In order to be able to make this lot a fighting force possessing razor sharp senses, artificial situations have to be injected from time to time. The first and foremost factor governing the body clock is the lighting, therefore white lighting between sunrise to sunset times matching the time zone that they are present in, to simulate daylight and thereafter, red lighting to simulate darkness is maintained. This change alone does not fool the body mechanism, hence, in addition special announcements are made for various meals. The red lighting besides helping the body clock also aids night vision when clandestinely looking at a target through the periscope at night, thus the requirement of maintaining sunrise and sunset timings relative to that position where the submarine is operating. The second most important factor is the sleep cycle of the human, which normally makes one sleepy at night but with frequent closing up of Battle Stations and maintaining a rotating shift round the clock, every individual does not get to sleep for more than three to four hours at a stretch. Thus the sleep rhythm is upset over a prolonged period of time something like 45 to 60 days, which indeed tells on the health of the body.
The third factor is the inability of the entire crew to go to the toilet at the same time, which they would normally have gone on land, due to paucity of space and limited toilets onboard, hence the physiological functions of the body have also to be readjusted to the vacancy of the toilets present which are generally two for the entire crew. All these factors weighing over a prolonged period of time can and do cause an upset in the body rhythms.
Submarines by virtue of being nocturnal fighting machines need to be more alert during dark hours whilst stealthily lurking below the water surface either tracking targets or collecting intelligence on the adversary. In order to keep the crew mentally alert, the Captain onboard a submarine is forced to play God and orders night into day and day into night. This can easily be simulated by white and red lighting. This change does not affect the mechanical clocks as watches are advanced or retarded by 12 hours, which basically means that watches remain running as they have been set for that time zone. What happens is that the submarine observes day during actual dark hours and night during actual daylight hours applicable in that particular time zone.
This change ensures a high standard of alertness during the actual night and rest during actual daylight hours, when submarine tactics dictate evasion from prying eyes in the sky. The disadvantage of this change over is that the body clocks of the crew are disrupted during the changeover and on reverting back for at least a couple of days each time, due to change in meal times with breakfast served at 1830h, lunch at 0100h and dinner at 0630h. This phenomenon at sea and its reverse effect on entry to harbour to reality is what can be termed as “Sub lag”. This gives way to a very strange phenomenon, the crews eat breakfast with dinner’s appetite and dinner with breakfast’s appetite for the first few days and on return to terra firma.
The repercussions of going against the body clock have been observed by many medical authorities but in these modern days when efficiency is paramount, tampering with the body clocks has become a way of life to the submariners. Abuse of the body by tampering with the chronobiologic rhythms on a regular basis could cause serious damage to the body metabolism in the long run.
Over the years, the submariner’s body clock has learned to cope with the changes in working hours in arduous conditions breathing from an artificial micro-climate maintained inside the submarine. On return to harbour, for the first few days, it is always difficult to get sleep at night.
The silent message to take home is that, submariners are a special breed of people highly motivated and willing to be trapped in sharks of steel for protection of their homeland.
Read more sea stories here: