A Circadian Rhythm is any biological phenomenon that involves self-sustained oscillation during 24 hours, caused by the earth’s rotation. Everyone in the world has an inbuilt “body clock” and it works much, in the same way, a finely tuned watch-making sure every system of the body works in unison to keep the body in homeostasis ( maintenance of the internal processes within tolerable limits).
There are clearly recognizable patterns of brain-wave activity, hormone production, cell regeneration, and other biological activities linked to each individual’s daily cycle.
How does it work and what makes it relevant?
The “suprachiasmatic nuclei” located within our brain, sort of act like a pacemaker and regulate the firing of nerve cells that seemingly control our circadian rhythm. Although it can’t be precisely said how exactly this part of the brain “keeps time”, it is scientifically established that it does rely on “outside” influences to keep the rhythm running.
Circadian rhythm is impacted by lightness and darkness received throughout the day. Most people’s clocks are naturally set to be the most alert in the mornings and late afternoon. For those who work long hours or graveyard shifts, there can be long term repercussions from ignoring the body’s natural cycle.
Circadian Rhythm Disruption (CRD)
Every time our normal 24-hour period Circadian Rhythm is altered or interrupted, it is bound to have physiological and behavioural impacts- resulting in what is known as “Circadian Rhythm Disruption”.
CRD is more apparent in shift work as now the shift timings are often at loggerheads with our internal body clock. This can result in a wide range of highly documented issues ranging from performance issues to accident and health problems.
Disruption of the biological clock and its impact on pilots
Flight and cabin crews operating on long-haul routes often have to cross multiple time zones, sometimes within the same day. The rapid changes in time zones often disrupt the natural biological cycle and result in what is called a “Jet Lag”. Yes, jet lag is also a Circadian Rhythm Disruption. Of all the stressors in aviation, Jet Lag is what seems to hit the hardest.
The effects of jet lag include health problems such as fatigue, irritability, reduced mental acuity, slow reaction time, mood swings and digestive issue. The decreased cognitive abilities can affect the performance of a pilot flying, on whose hands the entire safety of the flight operation rests.
Scientifically, the effects of jet lag seem to be more prominent when flying from west to east as it becomes difficult for the body to adjust to “losing time” when we journey east as opposed to flying west from the east where we “gain time”.
CRD as affecting pilot skills:
- Increased reaction time to sequential tasks that require time synchronization
- Impaired memory
- Emotional irritability, amongst many others
How can the pilots counter these inevitable effects?
It is a given that reduced sleep impairs cognitive performance, thereby making red-eye pilots more susceptible to human error incidents. Fortunately, there are prediction models in place that dictate the pilots when to eat, exercise and sleep based on their working schedule so they can be as alert as possible and get everyone to their destination safely.
Additionally. airliners are now employing new sleep monitoring devices that will help accurately gauge when a pilot may be getting overworked and too fatigued to fly safely.
How do you restore your bio clock and recover?
- Catch the sun: Exposing yourselves to sunlight has been scientifically proven to be beneficial in helping reset circadian rhythms. Additionally, this light therapy has a direct and positive effect by increasing brain serotonin levels.
- Be active: Taking a nap on arrival is the worst you can do as it sets the bio clock back to your home time. It is equally important to blend in with the local time(s) for all activities of the day.
Countering CRD while on duty
- Avoid pilot adaptation to a local circadian rhythm following trans-meridian flights with short layovers
- Alternate trans-meridian flights with intra-meridian flights which will enable a smooth transition to normal circadian rhythms
- Avoid night flights following a trans-meridian flight
- Use caffeine strategically to counter circadian rhythm sleepiness
- Avoid naps longer than 30 minutes as they involve “deep” sleep
Circadian Rhythm Disruption is also touted to lead to extreme chronic fatigue in the cockpit, the effects of which could just as debilitating as drugs and alcohol.
Nevertheless, pilots are trained extensively well and are very tuned in to their personal needs during a flight and hence you’re in highly qualified hands.
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