What is Jet Lag

Discover what is happening to your body when jet lagged

Jet lag is a lifestyle problem.  We can fly anywhere, anytime, in any direction.  Yet such freedom comes at a price.

Jet lag is stressful.  It is a chronic disruption in the body’s 24-hour circadian rhythm that cannot be ignored.  It comes in the form of fatigue, disorientation, headaches, insomnia, lack of motivation, lack of energy and sleep deprivation.  It can exacerbate ill health, contribute to constipation, dry skin, hormonal problems, burn out and adrenal fatigue.  Flight crew name symptoms of clumsiness, hormonal issues, weight problems, fatigue, sleep quality, forgetfulness and stress.  Jet lag is extremely punishing on the body. 

What is jet lag

Jet lag is a mismatch between internal and external clocks.  Our internal clock is known as the circadian rhythms.  The area in the brain charged with keeping time is called the suprachiasmatic nucleus (or SCN).  It has about 20,000 neurons who’s job it is to take cues from light in the environment to keep time.  This alignment is determined by factors such as exercise, hormonal shift and light.  The SCN is a control centre and aims to keep everything in sync.  Bright light exposure is the best way to create an advance or delay in circadian rhythms.  Light in the early morning makes you wake up earlier, whereas light at night makes you wake up later.  As well as light input, the SCN takes cues from your genes - you actually keep time all over the body. 

Your body clock wants to run like a Swiss watch.  Every single cell in your body, from hair tissue to your kidney cells, keeps its own internal clock.  You literally have trillions of internal clocks in your body. These rhythms anticipate waking and sleeping, controlling our hunger, mood, alertness, and blood pressure.  It is these clocks that become disrupted and out of sync with air travel.  Our internal clocks actually work to 24.5 hours a day, and this is why it is easier to travel west than east, as it is easier to travel in a direction that extends the day rather than shortening it. 

Our clock genes are controlled by melatonin (more below), your sleep hormone.  By flying to a different time zone, similarly working a night shift, jet lag results in the desynchronisation between external environment cues and your internal clock cellular cues.  They simply don’t match up.

Other factors worsen your jet lag, including your stress levels and the cabin environment.

Stress

The majority of us find travelling stressful.  We rarely adjust our sleep behaviour the week prior to a long haul.  If anything we are busy cramming in all we can before our trip.  By the time we get to the airport we have fought time, traffic, and endless cues through check in and security.  Unrested, out of sync, in a state of low level chronic stress – we board a plane.   

In flight, your body is under stress by the fact you appear to be travelling slowly but are in fact going very fast across time zones.  The California institute for human science noted in their research that the human body is checking its reference to the earth every 90 seconds.  No wonder we experience disorientation with jet lag.

The cabin

The cabin environment is also a huge stressor.  Long haul stewardesses were found to have higher saliva cortisol levels than short haul.  Cortisol is your fight and flight hormone, raised in times of stress.  Continuous raised cortisol leads to a state of poor immunity, ill health and exhaustion.

The cabin is pressured to the altitude of a small mountain at 8,000 ft.  Air is continuously bled off the engines and fed back into the cabin as dry air.  This lack of moisture in the cabin leads to an increase in dehydration, static and positive ions in the cabin.  All of these create enormous stress on the body, as we prefer humidity, less static and negative ions.  In addition, the engines generate a higher decibel noise, which is stressful to the central nervous system.  

Such an environment fosters a disordered sense of time and place.  The body has to work harder to function normally in an environment of low oxygen content, low air pressure and hypobaric in nature.  If you are stressed or unwell by the time you reach the airport, it is even worse for you. 

Deborah McTaggart is a registered nutritionist practising in Marylebone and Barnes, London and online. She works with corporate nutrition and individuals on healthy eating, with a special interest in Men's Health Contact me here for further information on nutrition plans.