THE RISE OF SLEEPWALKING ON FLIGHTS: WHAT FLIGHT CREWS NEED TO KNOW

Introduction

The ATAG Waypoint 2050 report indicates that “By 2050, it is expected that over 10 billion passengers will be carried by air some 22 trillion kilometres each year” [1]. According to the American Academy of Sleep Medicine, up to 4% of adult Americans sleepwalk every year. Other studies indicate that anywhere between 1.5% and 4% of adults sleepwalk, and the numbers are much higher for children. We can therefore estimate that the likelihood of flight crews encountering or having to manage incidents of onboard somnambulism will increase. While the epidemiology still requires further research in the aviation context, the evidence of how it will manifest onboard modern airliners will have to be borne out over time. The purpose of this article is to provide flight crews and industry professionals with some insights into the phenomenon, its causes and how to deal with it as part of safety initiatives.

Air travel often presents a unique set of challenges. Jet lag is the most common circadian rhythm disorder and is caused by a disturbance of internal circadian rhythm due to rapid travel across multiple time zones [2]. The disruption of circadian rhythms, the confined space, and the constant ambient noise of the aircraft can make it difficult for passengers to achieve restful sleep. Delayed Sleep Phase Syndrome (DSPS) and Advanced Sleep Phase Syndrome (ASPS) are circadian rhythm disorders where the body's internal clock runs on a different rhythm than the typical 24-hour cycle. In DSPS, the internal clock is delayed, leading to later bedtimes and wake-up times, while in ASPS, the internal clock is advanced, resulting in earlier bedtimes and wake-up times. Both conditions can cause sleep deprivation, daytime fatigue, and challenges in maintaining a socially acceptable sleep schedule, impacting daily life and social interactions. Air travel can exacerbate both conditions, making it harder to adjust to the new time zone and further disrupting the already misaligned internal clock, leading to more intense and prolonged experiences of jet lag. To combat the effects of these, many passengers turn to pharmaceutical sleep aids, hoping to ensure a peaceful journey. However, the use of these drugs in the unique environment of an aircraft can bring about unintended consequences, blurring the line between relaxation and embarrassing misbehavior.

There are multiple reports in the media regarding the incidents of sleepwalking on long haul flights, such as the case reported by Channel 7 News Australia “Sleepwalking man creates ruckus on long haul flight, doesn’t remember a thing”,  or the one reported by the Guardian newspaper “Plane passenger woke, stood, urinated on others and went back to sleep” . In that case on a flight from Anchorage to Portland, Oregon, the person in question was arrested when it landed and charged with offensive littering and criminal mischief. Another incident was cited in the Chicago Tribune, “Sleepwalking teen forces plane to land”. Many more incidents likely go unreported, though they are widely known to experienced flight crews. Thankfully, it's not as common as one might think, and aviation doesn't seem to contribute disproportionately to overall somnambulism rates. However, as global air traffic continues to rise, the likelihood of encountering sleepwalking on flights will invariably increase.

What is it?

Sleepwalking, also known as somnambulism, is a fascinating and often unsettling parasomnia. It involves complex behaviors, such as walking, talking, or even performing complex tasks, while the individual remains asleep. Though their eyes may be open, their brain is in a state of partial wakefulness, leading to a disconnect between their conscious awareness and their actions. This explains why sleepwalkers often appear disoriented and have no memory of their sleepwalking episodes upon waking.

Sleepwalkers are usually difficult to awaken, and even when they are, they tend to be confused and disoriented, with no recollection of the events that transpired during their sleepwalking episode. This makes sleepwalking a potentially dangerous condition, as individuals may engage in activities that could harm themselves or others. Sleep is a complex process that involves two distinct cycles, rapid eye movement (REM) sleep, characterized by dreaming and muscle paralysis, and non-rapid eye movement (NREM) sleep, which is further divided into four stages. Stage 1 represents the transition into sleep, characterized by a relaxed state and drifting thoughts. Stage 2 is light sleep, where brain waves slow down and muscle activity decreases. Stage 3, the deepest phase of NREM sleep, is crucial for physical and mental restoration. REM sleep, where vivid dreams occur, is characterized by rapid eye movements and near-complete muscle paralysis. These four stages are repeated in cycles throughout the night, typically 4-5 cycles per night. Sleepwalking occurs most often during stage 3, the deepest phase of NREM sleep, usually within the first or second sleep cycle. This is because it requires the deepest level of sleep to manifest. Naps are typically too short to reach stage 3 sleep, which explains why sleepwalking rarely occurs during naps. Given the sleep cycle where it occurs cabin crew can get a better idea of what phase of flight this kind of incident is more probable to occur. One would be able to infer that it is more likely to occur on long haul flights.   Understanding the interplay of these sleep stages and their relationship to sleepwalking provides useful insights to aviation professionals into the intricate nature of sleep and its various disorders that may manifest during longer flights.

"Sleepwalking is a behavior characterized by partial arousal during slow wave sleep (N4) [3]"

While it's often harmless, sleepwalking can be embarrassing, especially on an airplane.  Several factors trigger these episodes, including stress. The irregular sleep patterns and disrupted schedules common during air travel can also contribute to sleepwalking, as can certain medications, including sleep aids, antidepressants, and antipsychotics.  It can be challenging to recognize sleepwalking, as for all intents and purposes the individual appears awake.

The behavioral manifestation of sleepwalking is readily observable; however, its underlying neurological origins are less straightforward. The method of Polysomnography (PSG) is a comprehensive sleep study used by medical researchers to accurately diagnose sleepwalking by revealing the unique neurophysiological signature of this disorder. Obviously, flight crews won’t have access to such sophisticated methods and will simply have to learn to recognize the common signs by eye. These include a blank stare, glassy eyes in appearance, where their eyes are open, but the person appears unaware of their surroundings, or nonsensical speech, where they may speak but their responses are incoherent. Unusual behavior, such as attempting to open doors, rummaging through luggage, or even walking toward the exit, can also be indicative of sleepwalking.   While sleepwalkers are often unaware of their actions, their impaired judgment and perception can put them at risk of injury. This may include tripping over luggage, bumping into other passengers, or even attempting to open emergency exits. If you or someone you know experiences frequent episodes, it's essential to consult a healthcare professional before traveling. They can help determine the underlying cause and recommend appropriate treatment options to prevent its occurrence while in the air.

The medical field has taken an interest in these issues too. Lois E. Krahn, M.D., a professor of psychiatry in the Mayo Clinic College of Medicine and who holds a joint appointment in the Department of Psychiatry and Psychology and the Division of Pulmonary Medicine has been studying the phenomenon and took an interest in how sleeping pills have been causing issues onboard modern airliners and has been researching the effects for years.

What are the contributory causes?

There are certain medications and sleep aids that may potentially contribute to the incidence or increase the potential for it to occur. Hospitals and nurses are very familiar with these effects as they commonly guide unsuspecting patients back to their beds. "Twenty-nine drugs, primarily in four classes-benzodiazepine receptor agonists and other gamma aminobutyric acid (GABA) modulators, antidepressants and other serotonergic agents, antipsychotics, and β-blockers-were identified as possible triggers for sleepwalking. The strongest evidence for medication-induced sleepwalking was for zolpidem and sodium oxybate." [4]

Zolpidem for example, commonly known by the brand name Ambien, is a popular sedative-hypnotic medication prescribed for insomnia. While effective in promoting sleep, its use on planes has garnered attention for its potential to induce disinhibited behavior, leading to incidents of sleepwalking, talking, and even inappropriate physical contact with fellow passengers.

This phenomenon can be attributed to several factors. The continuous noise of the of the jet engines, the cabin lights, the constant intermittent sounds of call buttons and inter cabin communications alerts, and the potential for disruptions from fellow passengers and crew services all can interfere with the effectiveness of the medication, leaving individuals in a state of altered consciousness.  Air travelers sometimes combine alcohol and sleep aids which further exacerbates the risk of disinhibition. Alcohol potentiates the effects of sedatives, leading to unpredictable and potentially awkward behavior.

Ambien has been associated with known in-flight cases, but its not the only one, other sedatives, such as eszopiclone (Lunesta) and zaleplon (Sonata), carry similar risks. These medications, while effective in promoting sleep, can also lead to sleepwalking, confusion, and memory impairment in certain aviation environments. The use of these medications in individuals with pre-existing sleep disorders, such as obstructive sleep apnea can suppress respiratory drive and exacerbate existing breathing problems within the pressurized cabin setting. Research is sparse, but will increasingly become necessary in my view. 

Cabin Crew In-Flight Perspectives

Cabin crew occasionally witness the consequences of in-flight sleep aid use firsthand. Anecdotal accounts from flight attendants highlight the challenges of managing disoriented passengers, from sleepwalking in the aisles to inappropriate touching, flirting, confusion and even aggressive behavior. Being able to recognize sleepwalking is useful knowledge for in-flight crew.

When encountering a sleepwalker, it's important to handle the situation with care and sensibility. Similar to the way nurses are trained to treat patients in a hospital, gently guide them back to their seat, avoiding abrupt waking, as this can cause confusion or fear. Despite the myths, gently waking a sleepwalker is recommended for safety reasons, as they may be unaware of their surroundings and can arouse dazed and confused and feel threatened. When startled, sleepwalkers often react with a fight-or-flight response, potentially lashing out or falling, which could injure them or the person trying to wake them. Ideally elicit the aid of someone travelling with them, whom they are familiar with and can quickly recognize once awake. Understand that they may be experiencing an altered state of consciousness.  If the situation seems concerning or if the sleepwalker is exhibiting behaviors that could endanger themselves or others, inform a senior member of the crew to help handle the situation further.  If there are glass or cutlery, steel knives or forks on the tray tables as in the case of business or first class, ensure to remove those to reduce risk.

According to the American Academy of Sleep Medicine, “Results show that 22.8 percent of sleepwalkers presented with nightly episodes and 43.5 percent presented with weekly episodes. Additionally, a positive history of violent sleep related behaviors was found in 58 percent, including 17 percent who experienced at least one episode involving injuries to the sleepwalker or bed partner that required medical care.” [5]

These are rather high double-digit numbers, and when you consider that by 2050 its estimated that 10 billion people will be travelling by air annually, the skills to identify and mitigate these cases will have to form part of the training of professional flight crews.

Handling Sleepwalking Passengers

1. Approach with Caution

If they are traveling with a family member, colleague or friend elicit their assistance and ask if they are aware if there is a pattern of sleepwalking in the past. They can help you determine if that is in fact the case in this situation. Do not abruptly wake them, but according to the American Academy of Sleep Medicine it is fine to cautiously and tactfully wake a sleepwalker. It will require good judgement on the part of the intervening crew member upon carrying out a quick risk assessment and determine the best course of action. For example, in some cases the best outcome may be reached by gently guiding them to their seat and letting them get on with their rest. However, if there are cases where it may be better to gently wake the person such as they display persistent erratic wandering or inappropriate attempts at physical interactions with crew or fellow passengers. If you do lead them back to rest more ensure to keep an eye and monitor the individual. Remember abrupt waking can trigger confusion, anxiety, or even aggression. Speak softly and reassuringly and use a calm soothing voice to guide them. Recognize the passenger is not intentionally causing disruption and remain patient and understanding.

2. Guiding them Back

Gently lead them back to their seat. Do not grab or pull them, as this could startle them.

Offer verbal reassurance such as "It’s ok, I'm here to help you get back to your seat. That’s right, this way please". Clear any potential hazards on the aisle or access to the seat. Move obstacles from their path to prevent trips or falls and remove any potential hazards or dangers from the vicinity.

3. Important Considerations

If the sleepwalker is attempting to access restricted areas, gently redirect them to their seat and inform a senior crew member. Always apply your company policies and follow your safety and security protocols to ensure that neither is breached and handle accordingly. Just remember, a sleepwalker is not consciously aware of their actions, so, if possible, avoid harsh words or forceful handling. Record the incident in the logbook, noting the passenger's seat number and any unusual behavior. At the conclusion of the flight, they may not even remember or be aware of what they did during their somnambulist episode.

Sleepwalkers are not acting intentionally, so approach them with empathy and understanding they are essentially in a dream world in the threshold of consciousness between sleep and wakefulness. It could be likened to standing waste deep in the ocean shoreline, neither on land nor under water, it’s an in between state.  Prioritize passenger safety and prioritize gentle guidance over forceful intervention. Documentation of the incident is crucial for future reference and potential medical follow-up if any injuries, inappropriate behavior that may result in complaints from fellow passengers, or damage occurred. 

Indeed, anyone who has cared for young children or elderly individuals will likely have encountered sleepwalking firsthand. These incidents often require a delicate and understanding approach, demanding sensitivity, care, and compassion. This is especially true with children, who are often more vulnerable and may be particularly frightened by their own actions or unfamiliar surroundings as they rouse from the state of somnambulism. Approaching such situations with empathy and understanding, rather than harsh judgement, is an integral part of ensuring the well-being of those involved.

In conclusion, while understanding and managing sleepwalking incidents on flights is important for crew safety and passenger well-being, the lack of definitive diagnostic tools presents a challenge. It's essential to balance proactive measures with a cautious approach, ensuring that safety protocols are followed, while recognizing the difficulty in definitively proving sleepwalking as the cause for any disruptive behavior. Ultimately, the goal is to ensure fairness and equity for all involved, relying on evidence and sound judgement when addressing such incidents. As the prevalence of sleepwalking on flights potentially increases, we will require ever more nuanced strategies to effectively and above all respectfully address this complex situation.

Kind regards

Noel Cox

Principle Aviation Consultant at avcox

Author of The Air Traveler's Handbook

Citations and References

1. https://atag.org/news/new-report-outlines-path-to-net-zero-aviation-in-2050/#:~:text=By%202050%2C%20the%20industry%20will%20connect%20over%2010,than%202019%2C%20but%20also%20reaching%20net-zero%20CO2%20emissions.

2.      Wilson, Dr Sue, and Prof. David J. Nutt, 'Circadian rhythm sleep disorders', Sleep Disorders (Oxford Psychiatry Library), 2 edn, Oxford Psychiatry Library (Oxford, 2013; online edn, Oxford Academic, 1 Oct. 2013), https://doi.org/10.1093/med/9780199674558.003.0006, accessed 6 Aug. 2024.

3.      Broughton RJ. Sleep disorders: Disorders of arousal? Enuresis, somnambulism, and nightmares occur in confusional states of arousal, not in "dreaming sleep". Science. 1968;159(3819):1070–8. 10.1126/science.159.3819.1070 [PubMed]

4.      Stallman HM, Kohler M, White J. Medication induced sleepwalking: A systematic review. Sleep Med Rev. 2018 Feb;37:105-113. doi: 10.1016/j.smrv.2017.01.005. Epub 2017 Jan 29. PMID: 28363449.