HCAA SIAN 03-2024-Sleep disturbances and sleep hygiene

Is addressed to:

  • Operators of Commercial Air transport (CAT Fixed Wing and Rotorcraft)
  • Air Navigation Service Provider – ATCOs
  • Aerodrome Operators
  • Ground Handling Operators


Recipients must ensure that this notice is communicated to all members of their staff who need to take appropriate action or who may be interested in the contents of the notice.



In the context of improving aviation safety, the Aero Medicine and Medical Affairs Office has prepared relevant information concerning sleep disturbances and sleep hygiene.

Authored by:

Dr. Kalliopi Galanopoulou MB,BS , AME

Chief medical assessor HCAA

Dr. Dimitrios Dovris MD, PhD, AME

Deputy chief medical assessor HCAA

Dr. Odysseas Papaefthymiou MD, AME

ICAO subject matter expert related to public health



Fatigue from sleep disturbance is an important cause of potential in flight incapacitations or an inability to adequately and safely perform one’s work in the air or on the ground. It is imperative to identify causes of sleep disturbance and reduce or eliminate them and to adhere to the best possible sleep hygiene in order to promote health, wellbeing and the ability to function properly.  Sleep disturbances or a lack of sleep can occur due to organizational issues or can be due to organic or inorganic health issues.


Organizational issues for ground staff include prolonged working hours (large shifts, a large weekly workload, extended on call time, unsteady and slow roster systems, inadequate rest periods during work, inadequate free time between shifts and staff shortages.  Organizational issues for flight crews are similar, such as reduced down time with not enough consideration for traveling to and from the airport, long shifts or contiguous flights with inadequate rest time and large on call periods between working but also include time differences from departure to arrival countries, continuous noise levels and shifting light exposure while travelling between time zones.

Non organic health issues that cause sleep disturbance include a job with high levels of demands, anxiety and pressure, depression and anxiety as a result of interpersonal problems, poor pay, fatigue, unrealistic expectations and other social, emotional and economic issues.

Organic causes of sleep disturbance include obstructive sleep apnea, chronic pain, asthma and chronic obstructive airways disease, congestive heart failure, diabetes, abnormal thyroid function, urinary tract infections, prostate enlargement, acid reflux disorder, psychiatric disorders and dementia.  Medications and substances that can cause sleep deprivation are caffeine, nicotine, some decongestants, some asthma medications, some steroids, beta blockers (which in some people cause nightmares), some antidepressants and other stimulants such as cocaine and amphetamines.  Substances that can cause sleepiness and difficulty waking are benzodiazepines and other sleep medications (although benzodiazepines that wear off quickly can cause someone to wake in the middle of the night), some medications for epilepsy, alcohol, opioids, certain antihistamines, certain antidepressants, some muscle relaxants, certain antibiotics and other medications.


As far as organizational issues are concerned, it is imperative for operators to design working hours for staff considering:

  • that are not overtly long (no longer than nine hours daily, preferably less and 35-40 hour weekly),
  • adequate breaks for rest, meals and rehydration,
  • enough time between shifts to ensure commuting to and from work and having sufficient sleep, meal, washing and personal time,
  • to monitor time worked and ensure that rosters are being properly adhered to and not expanded,
  • shift work should follow short forward rotations (day, afternoon, night, rest) rather than be disorganized or have longer (e.g. weekly) rotations,
  • regular variation of tasks and job rotation to reduce fatigue from tiredness or boredom and
  • sequential night shifts kept to a minimum,

Furthermore, the shortage of staffing should be addressed so that emergency on call and last minute roster changes are kept to a minimum and special consideration in staffing should be taken to account for staff sick leave.

Adequate lighting and temperature control are paramount and great care needs to be taken for ground staff that may need to work during high temperatures (ensure adequate rest and rehydration and avoid the hottest hours as much as possible).


One of the most common causes of organic sleep disturbance that is often undiagnosed is sleep apnea.

Typically, this occurs in overweight or obese individuals that have many metabolic risk factors such as high blood sugar, high cholesterol, and high blood pressure, but it can also be found in thin people without all of these factors. Sleep apnea is when, during sleep, a person (either due to obstruction from their glottis or central nervous system issues) suddenly stops breathing for some seconds.

During this period of apnea, the levels of oxygen drop, and the carbon dioxide levels increase and eventually the body is driven to force a deep inspiration and begin to breathe again.

These episodes have multiple effects on the body, such as poor sleep quality and fatigue (waking up multiple times during the night and not achieving sufficient amounts of deep sleep), metabolic effects leading to worsening of obesity, increased lipid levels and increased insulin resistance and incidence of diabetes, increased blood pressure and more difficulty controlling hypertension with medications, arrhythmias (including serious ventricular arrhythmias), an increased incidence of depression and anxiety, reduced concentration ability and impaired work performance, amongst many others.

In most cases the sleep apnea cannot be corrected with surgery and requires a combination of the use of a CPAP mask (continuous positive airway pressure) and correcting as many metabolic problems as possible (losing weight, reducing cholesterol and blood sugar levels).

The suspicion of sleep apnea arises upon a detailed history regarding sleep patterns and the amount of tiredness and sleepiness during the day at rest and during activity. An important diagnostic tool used is sleepiness scales – the most widely accepted and used is the Epworth Sleepiness Scale – which asks specific questions on sleepiness during the day during various situations and generates a number that indicates the probability of having sleep apnea. If the probability is medium to high, a sleep study is then recommended. The subject is monitored for one night during sleep – electrocardiogram, encephalogram, respirations, oxygen levels and muscle movements – and a result is given is number of apnea events per hour. If this is significant, a CPAP mask is prescribed, which markedly reduces or even alleviates the apnea episodes and improves daytime alertness, metabolic indices, and cardiovascular indices.

It is extremely important for a pilot, ATCO and other workers in the air travel industry to be assessed and if necessary, treated for sleep apnea as this greatly improves performance and flight safety and reduces symptoms of fatigue and sleep deprivation. Also, if one feels sleepier and more tired than they should or they do not feel that sleep refreshes them at all, it is important to contact a respiratory physician for a sleep apnea assessment.


Many times, due to tiredness, poor scheduling and all of the other issues discussed previously, many people resort to the use of medications to help them sleep. Some of the most widely used medications are benzodiazepines – these are a restricted substance in air crew, pilots and other equipment operators, many of whom are subject to periodic drug testing. They can cause sleepiness, inability to concentrate or react – particularly during emergencies – reduced reflexes, poor work performance and major safety issues. These substances are also sometimes used as a relief for various anxiety and panic disorders, but they can only temporarily manage symptoms and cannot treat the underlying condition that may further complicate flight safety and also perpetuate symptoms that could otherwise be managed or alleviated at an earlier stage.

It is imperative to work through these issues with the help of peer support groups or mental health professionals from the early stages and it important to encourage employees to talk about and deal with these issues by providing a safe, nonjudgmental environment and also by further support and education of aeromedical specialists so that they can recognize issues early on and not approach them merely punitively but to provide further support and guidance.

Another substance commonly used, particularly in shift work or multiple changes of time zone, is melatonin. It is considered to be a more natural remedy for the inability to sleep and as a regulator of sleep/wake patterns. Unfortunately, it also has multiple side effects, which can affect flight safety. These include sleepiness, dizziness, headache, nightmares, depression, confusion, nausea, and diarrhea. It is of paramount importance to provide education about these issues, as melatonin is an over-the-counter medication and does not require a doctor’s prescription.

Alcohol is also used to help with sleep and anxiety. Alcohol reduces sleep quality and can have detrimental cognitive effects for many hours after consumption, even when blood alcohol levels have dropped to zero.  Overconsumption of alcohol can also lead to long term psychological, cognitive, physical and performance issues.


Sleep hygiene is an important concept which entails proper planning of sleep during and between trips or work shifts so as to maximize alertness and ability to function optimally. Adequate time needs to be allotted between shifts or flights that includes sufficient time for commuting, eating and self-care, and rest time includes travelling to and from work. It is important to understand that someone cannot fall asleep as soon as they get home and giving them limited rest time increases their anxiety levels and thus further reduces the ability to sleep properly.

Adequate planning needs to be made for sleep and naps before and after flights/shifts. Nighttime flying should be avoided as much as possible, as this creates a disruption of sleeping patterns and circadian rhythm. In multi crew, long haul flights, there needs to be a good organization of adequate rest/nap times of 20-40 minutes and things like basic activities and meals should be alternated between pilots so as not to have post meal fatigue at the same time. Meals on board should be light and healthy with fruit snacks available and adequate hydration. Meals just before shifts for ATCOs and ground staff should also not be too heavy. Before sleeping, beverages with caffeine such as coffee, tea, cola, chocolate should be avoided, and some light exercise can aid in relaxation and ability to get to sleep. Alcohol and sleep medications should be avoided as their effects can carry on for many hours.

Psychological issues that affect wellbeing and mental health also have a direct negative impact on sleep. It is very important to promote mental health in one’s workplace and not stigmatize people when they seek help or advice, but instead to promote this, by establishing peer support groups, guarding confidentiality, providing access to mental health professionals who can fulfill an advisory role and prevent the escalation of many psychological issues which could later create serious problems and flight incapacitation and other adverse safety issues. It is also important to not stigmatize staff that may be experiencing mental health issues and to provide adequate time off from work and a safe transition back to work for them. It is also important to advise aero medical examiners to openly discuss mental health issues and social factors and not to penalize the expression of negative feelings that do not pose a direct threat to flight safety but to act preventively and encourage their examinees to seek advice from mental health professionals at an early age.


A combination of good sleep hygiene, proper shift management by the operators, a healthy diet, exercise and mental health promotion, as well as avoidance of substances that can cause sleep deprivation or extreme sleepiness, are all important steps to improve sleep and reduce fatigue and ultimately to improve wellbeing and flight safety.