Feeling drowsy and fatigued behind the wheel is a common experience for drivers. Long highway journeys often end with heavy eyelids and fading concentration. But why does the act of driving cause tiredness, even on short trips? Is it normal to struggle staying alert while operating a vehicle? In this article, we’ll explore the reasons driving can induce sleepiness, the serious dangers of drowsy driving, and ways drivers can help reduce fatigue and remain vigilant on the road.
Is This Normal?
It is extremely common for driving to make people feel sleepy and tired. Estimates suggest that up to 20% of all motor vehicle accidents involve a drowsy driver. Many experts believe these numbers underestimate the scale of the problem. Sleepiness behind the wheel is a universal issue that affects all demographics of drivers to some degree. Factors like monotony, vibration, mental underload, and time of day all contribute to moderate fatigue being typical during driving. However, severe and dangerous levels of exhaustion are preventable with proper precautions.
Reasons Why Driving is Tiring
Feeling your eyelids start to droop and your focus drift while behind the wheel is very common. But what causes that nearly irresistible urge to nod off during long drives? There are several key reasons why driving induces fatigue.
|Repetitive road noise||Soporific auditory sedation||Drowsiness|
|Minimal visual stimulation||Limited novelty, changing stimuli||Wandering mind, zoning out|
|Inactivity||Remaining sedentary, limited exertion||Easy to doze off|
|High mental workload||Vigilance, concentration needed||Cognitive exhaustion|
|Circadian disruption||Delayed sleep times and hormones||Impaired alertness regulation|
|Microsleeps||Brief 1-10 second involuntary sleep episodes||Dangerous impairment and fatigue rebound|
1. Monotonous Road Noise
The constant low-frequency hum of road noise has a soporific effect after prolonged exposure:
- Auditory signals are received and processed even while you sleep. The monotony provides a tranquil backdrop that promotes drowsiness.
- Exposure to 60-100 dB noise for long periods raises epinephrine levels, which can increase fatigue once the initial stimulatingeffects wear off.
- Road sounds have very little informational value, failing to pique conscious attention and arousal. More varied audio input is more alerting.
Trying listening to upbeat music or thought-provoking podcasts to help counteract this auditory sedation.
2. Limited Visual Stimulation
Scanning repetitive road scenes fails to provide sufficient visual novelty to keep the mind engaged:
- Gazing at the unchanging view of pavement, guardrails, overpasses, and signs requires minimal visual processing, allowing your mind to wander.
- The visual cortex isn’t activated enough to maintain alertness, as these predictable sights become background noise.
- There is minimal visual information to capture “bottom-up” attention based on salient stimuli.
Looking for unique license plates, vehicles, or scenery can help boost engagement.
3. Passive Physical Inactivity
Driving involves prolonged sitting without much physical exertion, movement, or positional changes:
- The inertia makes it easy for drowsiness to set in, as the body prefers to conserve energy.
- Remaining sedentary reduces muscular exertion required to stabilize the body in motion.
- There is minimal “bottom-up” sensory feedback from overt motor actions.
Occasional stops to walk around for a few minutes can provide activity to briefly re-energize.
4. High Mental Workload
Driving necessitates constant active attention and vigilance, which drain mental resources:
- Visuospatial processing is needed to gauge distances between vehicles and lanes.
- Working memory enables navigating routes and directions while driving.
- Selective attention is required to concentrate on hazards versus distractions.
- Information processing facilitates quick reactions to changing road conditions.
These ongoing cognitive demands sap mental energy and concentration reserves.
5. Circadian Dysregulation
Driving for long periods overnight can disrupt your innate circadian sleep-wake regulation:
- Natural melatonin release in response to darkness can make you drowsy once night falls.
- Cortisol levels typically rise toward the morning, but lengthy nighttime driving delays this alertness signal.
- Late night driving may delay your bedtime, shortening sleep duration needed for restoration.
Plan overnight trips carefully, scheduling sufficient sleep before and after. Bringing light snacks to give you a quick lift can also temporarily counteract this circadian challenge.
Brief microsleeps lasting just 1-10 seconds can occur when extremely fatigued:
- During microsleeps, you are essentially asleep at the wheel, with complete driving amnesia afterwards.
- These lapses temporarily suspend sensory processing and motor control needed for safe driving.
- You may experience head snapping or drifting within the lane during microsleeps.
Microsleeps demonstrate severely impaired alertness. Pull over immediately and rest if needed.
Warning Signs of Dangerous Fatigue
Consult the table below to identify indications you shouldn’t drive drowsy:
|Blinking/fluttering eyelids||Microsleeps||Nap then switch drivers|
|Frequent yawning||Sleep pressure rising||Stop and sleep ASAP|
|Wandering thoughts||Impaired concentration||Pull over for rest stop|
|Missing exits or signals||Degraded vigilance||End driving for the day|
|Drifting within the lane||Lapses in control||Stop driving immediately|
When Driving Fatigue May Indicate a Medical Issue
Seek medical advice if you experience:
- Ongoing exhaustion despite adequate nighttime sleep
- Snoring or cessation of breathing while sleeping
- Difficulty staying awake for daily activities
Sleep apnea, narcolepsy, anemia, thyroid issues, or other disorders could be exacerbating driving fatigue. Consult a sleep specialist or primary care physician.
Tips to Avoid Driving Fatigue
Though some drowsiness is expected, drivers can take action to reduce severe fatigue:
Get 7-9 hours of sleep
Make sleep a priority and have consistent bed/wake times
Schedule trips for daytime
Avoid nighttime driving between 12-6am when people are biologically programmed to sleep
Bring a passenger
Having someone to converse with improves alertness through engagement
Take frequent breaks
Stop every 2 hours for light exercise, snacks, bathroom breaks, and short naps
Play stimulating music
Singing along activates the mind to promote wakefulness
Keep vehicle cool
Use A/C or open windows to prevent stuffiness
Drink coffee or energy drinks in moderation when extremely drowsy
Some prescriptions like sedatives increase drowsiness
Treat sleep disorders
See a doctor about potential issues like sleep apnea or insomnia
Use alertness devices
Try specialty devices that track eye movements or head motions
Driving-related fatigue is an extremely common experience with dangerous consequences when severe. Contributing factors like road monotony, vehicle vibration, and disruptive sleep schedules all trigger temporary drowsiness. Drivers should utilize preventive methods like getting sufficient nightly sleep, taking breaks, avoiding alcohol, adjusting vehicle temperature, and maintaining vigilance in order to stay safe. However, if exhaustion becomes unmanageable it’s critical to pull over and rest rather than pushing onward and risking catastrophic accidents.
Frequently Asked Questions
How many hours can you safely drive without stopping?
Most experts recommend taking a 15-20 minute break at least every two hours when driving long distances. Driving continuously for over 4-5 hours should be avoided to prevent accumulating extreme fatigue. Stops allow drivers to move around, get fresh air, nap, and consume caffeine to minimize drowsiness.
What foods help keep you awake while driving?
Snacking on fresh fruits and vegetables, nuts, seeds, whole grain crackers, and oatmeal can provide an alertness boost. Caffeinated drinks like coffee and green tea can also help temporarily increase wakefulness. Avoid heavy fatty and sugary foods that cause drowsiness.
Is cold air better than warm air for staying awake?
Yes, cooler air temperatures between 60-70°F are optimal to keep drivers alert by stimulating the senses. Warm vehicle interiors above 75°F increase fatigue. Briefly blasting cold air and opening windows can provide short-term alertness benefits.
Is driving at night more tiring than during the day?
Yes, fatigue is often worse when driving at night due to disruption of normal circadian rhythms causing natural drowsiness between 12-6am. Reduced daylight also suppresses alertness-promoting hormones. Night drivers should be especially vigilant taking regular breaks.
How can you tell if your fatigue level is dangerous?
Signs you are too tired to continue driving safely include yawning, eyelids drooping, blurred vision, inconsistent speed, wandering mind, difficulties remembering the past few miles, and microsleeps. Pull over immediately if experiencing any of these symptoms.