Ready to Drive
“are lights turned on?”
Naim S. Bashir, MD, FAASM
Diplomate American Board of Sleep Medicine
NH* Traffic Safety Administration
• Data based on police reports
• Drowsiness as a causing factor in:
– 100,000 crashes per year
– 076,000 injuries per year
– 001,500 deaths per year
*National Highway
NH* Traffic Safety Administration
• Data based on public survey – past year
• Drowsiness
– 55% felt drowsy while driving
– 02% felt drowsy and crashed
• Fallen asleep
– 23% fallen asleep while driving
– 03% fallen asleep and crashed
*National Highway
What is drowsiness?
“A state of impaired awareness associated
with a desire or inclination to sleep ”
• NOT ALWAYS
• “Forced Wakefulness”
• “Microsleeps”
Sleep
• Process – S (homeostatic)
• Process – C (circadian)
Process – S (homeostatic)
SLEEP
AWAKE
Process – S (homeostatic)
• Acute Sleep Deprivation
– Legal limit for blood alcohol concentration
(BAC) in all states is 0.08
• Awake 18 hours = BAC 0.05
• Awake 24 hours = BAC 0.10
• Chronic Sleep Deprivation – Sleep Debt
Process – S (homeostatic)
What happens in adolescents?
SLEEP
SLEEP DEBT
16 hours / week
AWAKE
6.9 hours / night
SLEEP NEED
9.2 hours / night
Process – C (circadian)
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•
•
•
Circadian pacemaker or “Biological Clock”
Resides at the base of the brain
Sets sleep / wake rhythm
Rhythm is altered by:
– Light
– Meals
– Exercise
– Social interaction
– Melatonin
Process – C (circadian)
ADULTS (7-8 hours)
MELATONIN
10:00 – 11:00 p.m.
MAXIMUM SLEEPINESS
LIGHT EXPOSURE
MEALS
EXERCISE
SOCIAL INTERACTION
LIGHT
07:00 – 08:00 a.m.
MAXIMUM ALERTNESS
PHASE DELAY
Process – C (circadian)
ADULTS (8 hours)
MELATONIN
What happens in adolescents?
LIGHT
10:00 – 11:00 p.m.
MAXIMUM SLEEPINESS
ADOLESCENTS (9.2 hours)
11:30 P.M.
PHYSIOLOGIC PHASE DELAY
08:30 – 09:00 a.m.
MAXIMUM ALERTNESS
BED TIME
• SUNDAY
RISE TIME THE NEXT DAY
12:30 p.m.
11:30 p.m.
~ 6 hours
• MONDAY
~ 7 hours
• TUESDAY
~ 7 hours
• WEDNESDAY
~ 7 hours
• THURSDAY
~ 7 hours
SEVERE
SLEEPINESS
06:30 a.m.
06:30 a.m.
06:30 a.m.
06:30 a.m.
06:30 a.m.
01:00 a.m.
• FRIDAY
~ 12 hours
• SATURDAY
~ 12 hours
01:00 p.m.
01:00 p.m.
TYPICAL SCHEDULE OF AN ADOLESCENT (sleep need 9.2 hours)
How alert is the adolescent driving
to school at 07:00 a.m.?
• Significant sleep debt to Process S
• Irregularities in Process C
• Severely sleepy / drowsy rather than in a
state of maximal alertness
• Force wakefulness – “micro-sleeps”
Adolescent driver surveys
• More than one half of the adolescent
drivers drove drowsy in past year
• 15% of drivers in 10th - 12th grades
drove drowsy at least once in a week
• One study of fall-asleep crashes indicated
that drivers were young (under age of 26
years) in 55% of the crashes
Causes of Sleepiness
• Inadequate sleepiness
• Presence of:
– Medical disorders
– Substance abuse
– Mental disorders
– Sleep disorders
Sleep Disorders
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•
•
•
•
•
Obstructive Sleep Apnea
Delayed Sleep Phase Syndrome
Narcolepsy
Restless Leg Syndrome
Periodic Limb Movement Disorder
Idiopathic Hypersomnia
Diagnosis of Sleep Disorders
• Consultation
– History
– Physical examination
– Sleep Log Review
• Nocturnal Polysomnography
• Multiple Sleep Latency Testing
Summary
• Adolescent sleep need is about 9.2 hours
of sleep per night
• Shift in biological sleep / wake rhythm
• Irregular sleep patterns are common
• Sleep Disorders are not uncommon
Drowsiness Prevention
• Establish a bedtime routine
–
–
–
–
Set a desired bedtime
Avoid exercise 4 hours prior to bedtime
Avoid large meals prior to bedtime
Start preparing ~ 1 hour before bedtime
• Bright light is best avoided
• Limited exposure to computers or television is helpful
• Social interactions are kept to a minimum
(text messaging, telephone conversations)
• Involvement in relaxing activities is helpful
(warm bath, reading, meditation)
• Preparing for next morning (lay out clothes, etc) may help get
a little extra time to sleep
Drowsiness Prevention
• Set a regular wake time
– Stay within 2 hours of week day wake time on
weekends (week day rise time: 06:30 a.m.
weekend rise time: 08:30 a.m.)
• Napping – “30 minutes”
• Get checked up for possible presence of a
Sleep Disorder if sleepiness persits
Drowsy Driving Prevention
• Do not drive if you know that you a prone
to becoming drowsy during the drive
• Take a power nap
• Drink a caffeinated beverage
• Loud music and rolling down the windows
do not work