Imagine this: you’re behind the wheel, cruising down the highway, but your brain is battling a fog of fatigue. Your reactions are slower, your concentration slips, and your eyelids feel like they weigh a ton. This isn’t just a bad night’s sleep — it could be a symptom of obstructive sleep apnoea (OSA), a common yet underdiagnosed condition that has serious implications for driving safety.
What Is Obstructive Sleep Apnoea?
Obstructive sleep apnoea is a sleep disorder where a person’s airway becomes partially or completely blocked during sleep, causing breathing to stop and start repeatedly. Each pause can last from a few seconds to over a minute and may happen dozens or even hundreds of times a night.
The Anatomy Behind OSA
OSA occurs when the muscles supporting the soft palate, tongue, and throat walls relax during sleep. This can cause the airway to narrow or close, especially in people with:
- A naturally narrow airway
- Enlarged tonsils or uvula
- Obesity
- Weak airway muscle tone
Each time breathing stops, the brain briefly wakes the sleeper to reopen the airway — but these awakenings are so short, the person may not even be aware it’s happening. Over time, this disrupts restorative sleep and leads to chronic fatigue and poor concentration during the day.
Oxygen Loss to the Brain: The Silent Threat
One of the most serious effects of OSA is intermittent hypoxia — periods during sleep when the brain gets less oxygen than it needs.
Why Does This Happen?
When the airway is blocked, breathing temporarily stops or becomes shallow. This leads to a drop in blood oxygen levels (sometimes significantly), depriving the brain of a steady supply of oxygen. These oxygen dips can occur dozens or hundreds of times per night, often without the person waking fully.
What Are the Consequences?
- Cognitive impairment: Chronic oxygen deprivation can affect memory, attention, and decision-making — all crucial for safe driving.
- Slowed reaction times: Just like being under the influence of alcohol, low oxygen levels dull the brain’s ability to process and respond to stimuli.
- Mood and alertness changes: Reduced oxygen can cause irritability, poor concentration, and even symptoms of depression or anxiety, further affecting driving ability.
How does this Affect Driving?
Driving safely relies on alertness, quick reflexes, and good decision-making — all of which are compromised in someone with untreated OSA.
- Microsleeps can occur while driving, causing momentary lapses in attention.
- Reaction times slow, increasing the risk of collisions.
- Impaired concentration and reduced situational awareness make it harder to respond to unexpected hazards.
- Studies show drivers with OSA are over three times more likely to be involved in a crash.
Medical Fitness to Drive: What the Guidelines Say
According to Austroads medical standards for licensing, a person is not considered fit to hold an unconditional licence if any of the following apply:
- They have confirmed sleep apnoea syndrome (diagnosed via sleep study) with moderate to severe excessive daytime sleepiness
- They experience frequent drowsiness or sleepiness while driving
- They have had one or more crashes caused by inattention or sleepiness
- Their treating doctor believes they pose a significant driving risk due to their sleep disorder
Conditional Licensing
A conditional licence may be granted if:
- The person is compliant with treatment, such as CPAP therapy
- There is a satisfactory response to treatment, with reduced sleepiness and improved function
- Periodic reviews confirm continued safety to drive (including OT driving assessments)
If you or someone you know requires an occupational therapy driving assessment, please feel free to contact Driving Well Occupational Therapy to arrange an assessment.
How Sleepy Are You? Try the Epworth Sleepiness Scale (ESS)
The Epworth Sleepiness Scale (ESS) is a simple, self-reported questionnaire used to assess daytime sleepiness — a key symptom of obstructive sleep apnoea. It asks you to rate your likelihood of falling asleep in common situations on a scale from 0 (would never doze) to 3 (high chance of dozing).
Situation | Score (0–3) |
1. Sitting and reading | |
2. Watching TV | |
3. Sitting inactive in a public place (e.g., a theatre or meeting) | |
4. As a passenger in a car for an hour without a break | |
5. Lying down to rest in the afternoon when circumstances permit | |
6. Sitting and talking to someone | |
7. Sitting quietly after a lunch without alcohol | |
8. In a car, while stopped for a few minutes in traffic |
ESS Score | Interpretation |
0–7 | Normal sleepiness |
8–9 | Mild sleepiness |
10–15 | Moderate sleepiness (may require medical attention) |
16–24 | Severe sleepiness (strongly consider evaluation for a sleep disorder) |
A high score doesn’t diagnose sleep apnoea, but it does signal a need for further investigation — especially if you’re experiencing other symptoms such as loud snoring, gasping during sleep, or frequent morning headaches.
Obstructive sleep apnoea can deprive the brain of oxygen, disrupt concentration, and cause extreme drowsiness — all of which pose a serious risk to road safety. But with proper diagnosis, treatment, and support from professionals like OTs, people with OSA can continue to drive safely and responsibly.
If you’re experiencing signs of fatigue, poor concentration, or excessive daytime sleepiness — especially if you score high on the Epworth Sleepiness Scale — please reach out to your doctor. Early diagnosis and treatment can dramatically improve your quality of life and reduce the risk of a serious crash.
If you or someone you know requires an occupational therapy driving assessment, please feel free to contact Driving Well Occupational Therapy to arrange an assessment.
