With the advent of high-speed jet travel, the world has become a much smaller place. Just a pity that instead of experiencing excitement when arriving at a new destination, you experience severe tiredness, and you battle to stay awake to drink in the sights.
The dreaded fatigue after a long flight is called jet lag, which is caused by travelling at great speed over two or more time zones, with the body moving much faster than the brain and bodily processes can adapt. Jet lag happens when there is a disconnect between the external light and dark cycle of night and day at your destination, and your body’s internal clock (referred to as our circadian rhythm) which is still on the light and dark cycle from home.
The distinguished looking pilots with bold signs of rank on their epaulettes and attractive flight attendants in uniform tell us one thing for sure – they have glamorous jobs. Surely, the ones working international flights that regularly cross many time zones should be immune to jet lag.
What exactly is jet lag?
Travelling at great speeds over many time zones unbalances the body’s biological clock, which is controlled by a tiny organ in the brain, the pineal gland. Cells in the eyes send light and darkness messages to the pineal gland, with darkness triggering the pineal gland to release a sleep-inducing hormone – melatonin – into the blood stream. Melatonin is a neurohormone that is commonly known to prepare the body for sleep. It plays a crucial role in regulating the body’s circadian rhythm, also known as the biological clock, in the 24-hour sleep-wake cycle.
Abrupt changes in time zones due to long-distance, high-speed air travel, with light and darkness signals at different times than what the body is used to, upsets melatonin production and unbalances the body’s sleep-wake cycle, which plays an important role in the body’s circadian rhythms. Changes in these biological functions, coupled with physical and emotional stress, cause jet leg.
Symptoms of jet lag may be different for different individuals, with the most common symptoms being fatigue, headaches, inability to concentrate, irritability, an upset stomach, sleeplessness, or sleepiness.
Apart from the sleep-wake cycle, other physiological and behavioural processes that form part of the body’s circadian rhythms include digestion, regulation of temperature, and hormone secretion. Certain time cues, such as light and darkness, regular mealtimes, and work/rest schedules, all keep the circadian “clock” set to the appropriate time of day. Crossing time zones results in disruption of the circadian rhythm and can produce symptoms similar to loss of sleep.
Symptoms of jet lag are usually worse when flying over many time zones from west to east, against the direction of the sun, as the day is artificially shortened. It takes about one day for every time zone that is crossed to recover from jet lag.
To date, there is no immediate cure for jet lag.
Other flight hazards affecting air crew:
Passengers and other mere mortals flying long distance over more than two time zones can make provision at their destination to allow a day or more to recover from jet lag.
Behind the scenes, the seemingly glamorous jobs of the aircrew may well be more hazardous than glamorous. Apart from jet lag that may be worse for the ones flying regularly to different destinations, in different directions, and over different time zones, there are a number of other hazards that can affect aircrew.
Inadequate restful sleep:
Like food and water, sleep is a vital physiological function that is necessary for survival. The conditions leading to jet lag also create havoc with normal sleeping patterns, as aircrew would be working during their normal sleep hours and in many cases have unpredictable shift work hours, associated with different flight destinations. Many aircrew members have a rotational, non-permanent, and often irregular roster.
Research findings show that cabin crew have a high prevalence of fatigue and nearly half of them experience excessive sleepiness due to poor sleep quality. They were vulnerable to sleep disorders with an elevated risk for insomnia. Sleepiness at the end of a trip was sometimes so severe that some cabin crew reported falling asleep while driving home.
Regular inadequate restful sleep means sleeping fewer hours than your body needs, resulting in a condition called sleep debt. Sleep debt can have a cumulative effect, if one regularly gets less sleep than you should, it can negatively impact your health, such as feeling tired, losing the ability to remain focused and efficient, weaken your immune system, degrade judgement, slows reaction time, and make it more difficult for your brain to process and store information. The only way to repay sleep dept is to catch up with lots of sleep.
It is reported that nine hours into his 33-hour flight, Charles Lindbergh (flight pioneer and in May 1927 the first person to fly alone across the Atlantic) wrote in his journal “…nothing life can attain, is quite as desirable as sleep.”
Prolonged work schedules:
The work schedules of aircrew can be influenced by several important factors:
- Time since being awake: This can be prolonged prior to flying due to the effects of jet lag with inadequate quality sleep and early awakening, checking out of hotels and travelling to the airport for flight check-in, and delays in pre-flight procedures due to weather delays or mechanical problems.
- Time on tasks: This refers to the time spent on pre-flight planning and going through pre-flight checklists, activities during the flight, and after-landing checklists and other tasks.
- Type of tasks: This depends on the responsibilities of the particular crew member, the type of aircraft, and the nature of the flight.
- Extensions of normal duty periods: This can occur due to events that can prolong a flight for longer than scheduled, for example delays due to poor weather conditions, or rerouting due to congested air traffic.
- Cumulative duty times: Fatigue can worsen in the event of consecutive flying days with minimal crew rest periods, adding to sleep debt.
Dehydration:
Dehydration is highly possible during air travel, caused by dry cabin air, a lack of water within the body cavities due to high body temperature, excess caffeine, the use of antihistamines, and inappropriate fluid intake.
The effects of jet lag can be minimized by drinking plenty of water before, during, and after a flight. The suggested amount of water to drink is one liter of water for every six hours of flight, in addition to any beverages. Many soft drinks, tea, and coffee contain caffeine and sugar, which may compromise absorption of the water content. In addition, coffee and alcohol act as diuretics.
Dehydration results in fatigue, diminished blood flow to the muscles, and reduced kidney function, while contributing to fuzzy thinking, dizziness, and poor decision-making.
Cosmic ionizing radiation:
Cosmic radiation exposure on an aircraft includes both the ever present galactic cosmic radiation, and infrequent solar particle events. Passengers are exposed to minimal cosmic ionizing radiation, while aircrew experience more exposure due to regular flying.
Cosmic ionizing radiation (commonly referred to as cosmic radiation) is a form of ionizing radiation that comes from outer space, of which a small amount reaches the earth. Cosmic radiation consists of high-energy charged particles, X-rays, and gamma rays produced in space. The charged particles react with the earth’s atmosphere to produce secondary radiation, which reaches the earth. Cosmic radiation exposes the body to radiation in a manner similar to exposure from a medical X-ray.
Aircrew are not only exposed to galactic cosmic radiation, but at times also to solar particle events, commonly known as “solar flares”. Solar flares occur unpredictably and consist of intense bursts of explosive events, lasting from minutes to hours, on the surface of the sun. People on the surface of the earth are mostly protected from the effects of solar flares by Earth’s atmosphere and magnetosphere, but aircrew is more exposed due to flight altitude. Solar flares are a rare occurrence, and authorities estimate that pilots fly through a solar flare about six times over an average 28-year career. A pregnant aircrew member who flies through a solar flare may be exposed to more radiation than is recommended during pregnancy.
The exact amount of cosmic radiation aircrew is exposed to, and the health effects, are not exactly known, but the National Council on Radiation Protection and Measurements in the USA reported that at 3,07 mSv (milli sieverts), aircrew have the largest average annual effective dose of all radiation-exposed workers. International guidelines, such as provided by the International Commission on Radiology Protection, recommend limits of exposure to a total of 100 mSv in 5 years.
The Federal Aviation Administration in the USA has developed a handy tool that aircrew can use to easily calculate their exposure to cosmic radiation during flights. The program is called CARI-7 and can be downloaded for free from the FAA’s website. (www.faa.gov)
Job stress:
Having a glamorous job doesn’t mean you are exempt from high levels of job stress. Aircrew have to deal with heavy job demands and pressures, such as working long and irregular hours, extended time away from home and loved ones, unpredictable schedule changes, sleep disruption, dealing with unpleasant passengers or co-workers, and traumatic events during in-flight emergencies or extremely bad weather and turbulence.
Stress can vary from a stressful event of an acute but short-term nature, to chronic prolonged stress due to experiencing heavy demands over an extended period of time. Chronic long-term stress, however, keeps the body on high alert and causes continuous high levels of the stress hormone cortisol to be released.
Elevated levels of cortisol over the long term have ill-effects on physical and mental health, by suppressing the functioning of the immune system, or even failing to regulate it. Apart from predisposing us to viruses and infections, chronically elevated cortisol levels can cause resistance to cortisol in cells and tissues, leaving the door open to inflammatory related diseases.
Other detrimental effects on the body include over-eating or binge eating with increased fat storage, leading to weight gain and reduced insulin sensitivity. It can also contribute to high blood pressure and the formation of artery-clogging deposits.
Effects on the brain include an increased interconnectivity between the emotional centers in the brain (causing a constant fight-or-flight response), with lower connectivity to the rational part of the brain. This can lead to illogical and hyper-emotional behavior patterns. Other effects on the brain can include brain cell shrinkage and premature brain cell death. The influence of these factors on brain functionality can result in poor memory formation, poor attention span, poor focus, and a decline in cognitive potential and motivation.
Chronic stress can also damage genetic material (DNA), resulting in biological changes that speed up the process of aging, and increase the potential to develop chronic diseases and adverse health conditions.
Cabin air quality:
An unseen hazard that aircrew are not always aware of, is the effect that the quality of the air in the cabin may have on their health. Problems with ventilation systems can result in unsafe levels of carbon monoxide or carbon dioxide when cabin air becomes contaminated with breakdown products, such as leaks from heated engine oil or hydraulic fluid.
While changes in cabin pressurization are usually quickly corrected, rapid or even moderate loss of pressurization is first felt on the eardrums and other internal sinuses. In serious cases it can result in a condition called hypoxia when tissues and cells in the body do not get enough oxygen to function correctly.
Sick passengers can expose aircrew to communicable diseases, which are illnesses that spread from one person to another. These diseases can spread through direct contact with a sick person, breathing in airborne viruses and bacteria (such as COVID-19), contact with bodily fluids and blood, and contact with contaminated surfaces.
Aircrew and even passengers may be exposed to pesticides used for disinfection, as some countries require that in-bound aircraft must be treated with pesticides to prevent the spread of insects or diseases carried by insects. Exposure may result in respiratory symptoms, headaches, nausea, dizziness, or skin and eye irritation.
Studies have indicated that aircrew, especially flight attendants, are more likely than other workers to have respiratory symptoms and diseases, such as a dry or sore throat, a stuffy or runny nose, chest illness, cold or flu, and chronic bronchitis.
Musculoskeletal disorders:
Musculoskeletal disorders refer to short or long-term injuries that can occur to muscles, tendons, and nerves, as well as the bones and ligaments that form the supporting structures of the body.
Less glamorous than walking through the arrival hall in full uniform, is pushing or pulling a heavy food cart up and down the aisle during the flight. Flight attendants are also prone to injury due to heavy or overhead lifting, prolonged standing, awkward postures such as twisting at the waist, or constrained postures. Sudden airplane movements or turbulence can cause imbalance and increase the risk of injury due to a fall.
If possible, avoid or limit awkward postures such as stooping, bending, or twisting at the waist, lifting heavy items overhead, or lifting from below the knees.
Tips to deal with jet lag and other hazards:
Aircrew has over time developed some strategies that can contribute to a smoother transition across time zones, which may help to make jet lag symptoms go away sooner or make them less severe. Their tips can also help normal air travelers. These include:
- Getting on your destination’s sleep-wake cycle quickly.
- Avoid unfamiliar food and choose food that your body knows how to digest.
- Drink lots of water, at least a liter for every six hours of flight. Proper hydration is essential to help combat the effects of jet lag.
- Avoid coffee and alcohol, which can make one more dehydrated, as dehydration worsens the effects of jet lag.
- Focus on getting enough quality sleep.
- If you are going to travel east to west, go to bed later and wake up later for several days before your departure. For travelling from west to east, go to bed earlier and wake up earlier. This can help your body to adjust sooner to new sleep patterns.
- Adjust your mealtimes for a few days before departure to match when you will be eating at your destination.
- Try to move around the cabin if possible and do some exercises in your seat, such as breathing deeply, contracting and releasing your leg muscles, lifting your arms overhead, turning your head, rolling your feet, and raising your knees.
- Stay awake before the flight and during the flight, as the accompanying exhaustion ensures tiredness at your destination, making it easier to go to bed at your destination’s bedtime.
- During the flight, aircrew often have coffee to help them stay alert, or opt for bananas, as they are rich in vitamins and natural sugars to provide a quick wake-up boost, without the risk of a caffeine crash.
- When drinking coffee to help you stay awake, also drink more water to counteract the dehydration effects of caffeine.
- Some aircrew members try to stick to one time zone, by consciously living according to either the time zone they departed from or the new time zone to maintain a sense of consistency, especially during short layovers.
- Many aircrew members keep their watches set to the time zone of their base to avoid confusion.
- A strong support system from fellow travelers, or aircrew colleagues that work and travel together, helps to motivate each other to stick to sleeping and mealtime schedules, and adapting to the new time zone.
- Eating light meals that are easily digestible helps, as heavy meals can make you feel sluggish and disrupt sleep patterns. Light, healthy meals can help the body replace essential nutrients lost while flying.
- Utilize crew rest periods during flight to take a nap, or rest with your eyes closed when it is not possible to sleep.
- Once home, jet lag really kicks in and it is best to get as much rest and sleep as possible. Jet lag takes at least 48 hours to recover from.
Conclusions:
While traveling enriches your life, long distance flights over different time zones inevitably result in jet lag, as your body moves much faster than your brain and circadian rhythms can process the time change. The result is the dreaded fatigue and other symptoms associated with jet lag.
While researchers have yet to uncover a cure for jet lag, it remains a formidable challenge for air travelers and is even worse for aircrew, for whom the glamour of the job soon wears off. Trying out and adopting the strategies used by many aircrew members can help to reduce the effects of jet lag.
In spite of the effects of jet lag and other hazards, one wonders how aircrew still manage to look glamorous when entering the arrivals hall after a long flight?
References:
Jet lag. Published 6 October 2022. Centers for Disease Control and Prevention. USA. (www.cdc.gov)
Jet lag. Cleveland Clinic. USA. (A nonprofit multi-specialty medical centre that integrates clinical and hospital care with research and education.) (www.clevelandclinic.org)
Mastering jet lag: Flight attendant’s proven strategies to beat fatigue and stay energized. Published 16 October 2023. Eton College. Canada. Linkedin. (www.linkedin.com)
Six ways flight attendants live with jet lag. Published 5 January 2023. Simple Flying. (www.simpleflying.com)
15 Ways to overcome the jet lag known by flight attendants. Published 16 June 2016. Bitnine. (www.bitnine.net)
Fatigue and sleep in airline cabin crew: A scoping review. Published February 2023 in the International Journal of Environmental Research and Public Health. Pubmed Central. National Centre for Biotechnology Information. US National Library for Medicine. National Institutes of Health. USA. (www.ncbi.nlm.nih.gov)
HEALTH INSIGHT
February 2024