The F Word of Aviation
Fatigue.
It’s one of those words that tends to lower voices in aviation. Not because it’s uncommon, but because of what admitting it can imply.
The industry has moved forward, without question. Over the past 10–20 years, CRM training has opened space for better conversations. There are airlines and private jet operators that genuinely recognise fatigue as a safety issue rather than a personal flaw and that makes a real difference.
And still, fatigue remains one of the hardest things for the crew to speak about openly.
“I am fatigued and not fit for duty”. Those words require courage. They also require confidence that they will be received without judgment, consequence, or subtle doubt. And that judgment doesn’t always come from the employer. Sometimes it comes from colleagues. Sometimes from ourselves. In reality, that confidence isn’t always there.
So people hold it together. They manage. They push through. The system has long rewarded composure over honesty.
Fatigue is not only subjective. It is also physiological. The body reflects it in ways we can clearly observe and study.
Cortisol - When cortisol loses its natural daily rhythm (high in the morning, low in the evening), the body struggles to switch between alertness and rest. This often feels like being tired but wired, difficulty falling or staying asleep, feeling on edge, and never feeling fully rested.
Inflammatory markers (such as CRP and IL-6) - In a well-recovered body, inflammation rises briefly when needed and then settles. When inflammation stays mildly elevated, the body remains in a low-level stress state. This can feel like heavy, lingering fatigue, muscle aches, slower recovery, low mood, and a sense that rest does not fully reset the system.
Iron status (ferritin and haemoglobin) - Iron supports oxygen delivery and energy production. Under fatigue and chronic stress, iron stores can gradually decline or become poorly utilised. When this happens, muscles and the brain receive less oxygen than they need. The result is disproportionate tiredness, reduced stamina, breathlessness on effort, and difficulty concentrating.
Vitamin B12 and folate - Low levels interfere with how efficiently the nervous system works. People often experience brain fog, slower thinking, low energy, mood changes, tingling sensations, and mental fatigue that feels disproportionate to activity levels.
Thyroid markers - The thyroid sets the body’s metabolic pace. With prolonged stress and fatigue, thyroid signalling can slow as the body moves into conservation mode. This can show up as persistent tiredness, feeling cold more easily, slower metabolism, weight gain, reduced stamina and brain fog.
Glucose regulation - When blood sugar becomes unstable, energy supply to the brain fluctuates. This often feels like energy spikes followed by crashes, shakiness, irritability, and poor concentration.
Magnesium - Magnesium supports relaxation, muscle function, and nervous system balance. Stress and fatigue increase magnesium loss through urine and sweat. This can feel like poor sleep quality, muscle tension or cramps, heightened stress sensitivity, restlessness, and difficulty fully relaxing or recovering.
And still, the numbers don’t capture everything.
Fatigue is also mental. Emotional. Cumulative.
What if the system offered more than compliance pathways?
What if there were non-punitive, preventative spaces where crew could talk, before fatigue becomes a report, an incident, or a medical limitation?
What if there were non-punitive, preventative spaces where crew could talk, before fatigue becomes a report, an incident, or a medical limitation?
Sometimes, it isn’t a protocol that’s missing.
Sometimes, it’s a conversation.
Peer support programmes exist, and they play an important role within aviation. When they are well-resourced, thoughtfully designed, and led by the right people, they can offer meaningful support. There are moments, however, where the support needed is less structured and more human, particularly when someone is struggling to put their experience into words.
Fatigue does not always require escalation. Often, it requires recognition. Being heard early rather than managed later.
Fatigue is not the failure.
Silence is.
If we want crew who can truly show up for safety, for passengers, and for each other, fatigue cannot remain the unspoken F word.
Not hidden behind professionalism.
Not carried behind a smile.
Not left unaddressed.
Creating safe spaces to speak openly, to be heard, and to talk about fatigue without fear is something we can all contribute to.
Ivana
