The Importance of Sleep and Sleep
Hygiene: Practical Clues for the
College Student
Roseanne Armitage, Ph.D.
Professor
Director - Sleep and Chronophysiology Laboratory
University of Michigan
M
Sleep &
Chronophysiology
Laboratory
Functions of Sleep
SWS – basic sleep drive – rest, recovery &
homeostasis
Body& blood cell work, immune system,
Keep circadian rhythms entrained
Stage 2 – maintain vigilance while sleeping
REM- Memory consolidation,
development of neural connections
in childhood
M
Sleep &
Chronophysiology
Laboratory
RAW DATA
STORAGE
DIGITIZED VALUES
AMPS
PSA or PAA
A/D CONVERSION
BOARD RESIDENT
IN COMPUTER
POWER
SPECTRA
% ZERO-CROSS
% FIRST DERIVATIVE
POWER
SAMPLING RATE
128-1000Hz
OFF-LINE VISUAL SLEEP-STAGE
SCORING
BETA
SIGMA
ALPHA
THETA
DELTA
12-32 Hz*
12-16 Hz
8-12 Hz
4-8 Hz
0.5-4 Hz
*FREQUENCY BAND WIDTHS DIFFER BETWEEN LABORATORIES
REM
Stage 4
HEALTHY NORMAL CONTROL
Awak
e
Move
REM
Stg 1
Stg 2
Stg 3
Stg 4
SOS: 23:54:00
TIME OF NIGHT
WUT:
08:51:30
% REM:
13.3
7.5
SLEEP EFFICIENCY: 96.8% % STAGE 1:
REM LATENCY:
94.5 min % STAGE 2: 57.0
SLEEP LATENCY: 7.0 min % STAGE 3: 16.9
% STAGE 4:
3.5
How much sleep do you need?
• Not everyone needs the same amount
of sleep Natural short and long
sleepers
• BUT sleeping less than 6.5 or more
than 9 hours is associated with 1.7 x
greater mortality & risk of disease.
M
Sleep &
Chronophysiology
Laboratory
Is it Enough Sleep?
 More than 40 % of adults have sleep
complaints
 25 % women & 16 % men
 # 1 Complaint: Feeling unrested
 # 2 Complaint: Difficulty Falling Asleep
Among college students 71 % had sleep
complaints in 2000 compared to 24 % in
1978
M
Sleep &
Chronophysiology
Laboratory
How Has Sleep Changed Historically?
 Estimated 8-9 hrs in early 20th Century
 7-8 hrs mid 1980s-2002
 College Students:
 1980s reported 7-7.5 hrs
 2002 reported 6-6.9 hrs
 Going to bed later is the culprit
 Bedtime is 1-2 hrs later
than it was 25 yrs ago
M
Sleep &
Chronophysiology
Laboratory
Napping
 30-50 % of students nap
 Nappers have delayed bedtime of >1 hr
 30 % naps >1.7 hrs
 Mostly late afternoon naps
 Sleep >1 hr less than non nappers
M
Sleep &
Chronophysiology
Laboratory
Consequences of Sleep Loss
 Poor academic performance correlated with
insomnia & poor sleep quality
 Automobile Accidents: Fatigue is a leading cause
 Minor medical Illness: Cold & Flu rates higher in
poor sleepers
 Circadian dysregulation: Creating Jet Lag in the
home environment
 Psychiatric Illness:
Depression & Anxiety
M
Sleep &
Chronophysiology
Laboratory
Sleep & Depression

Sleep disturbance > 2 wks is a risk factor for
the development of depression

Sleep abnormalities are common symptoms of
depression: >80% pts

Often the presenting symptom: Common to
notice the sleep problem first
M
Sleep &
Chronophysiology
Laboratory
Sleep & Depression
If sleep problems persist into
clinical remission:




Worse clinical outcome and increased
risk of relapse in recovering patient
Increased risk of suicide
Daytime fatigue/ reduced functioning
Worry about insomnia may cause
further insomnia and anxiety
M
Sleep &
Chronophysiology
Laboratory
Depression in College Students
 Incidence is 2 x greater than general
population
 Approximately 20 % of students
 Often goes undiagnosed and untreated
 Increasing risk of another episode
M
Sleep &
Chronophysiology
Laboratory
Sleep and Depression in College
Students
 Worsening of depression and sleep problems at
exam time (particularly in males)
 Minor medical problems 2-4 x more prevalent
in depressed students with sleep problems >2
wks duration
 Attending University does increase
both incidence of sleep problems
& depression
M
Sleep &
Chronophysiology
Laboratory
DEPRESSED PATIENT
Awake
Move
REM
Stg 1
Stg 2
Stg 3
Stg 4
SOS: 01:04:00
TIME OF NIGHT
SLEEP EFFICIENCY: 79.2%
REM LATENCY:
49.0 min
SLEEP LATENCY: 6.0 min
WUT: 08:51:30
% REM:
% STAGE 1:
% STAGE 2:
% STAGE 3:
% STAGE 4:
16.9
17.0
46.0
0.0
0.0
Sleep & Biological Rhythms
 Ultradian <24 hrs
 Most common 90 min REM/NREM sleep cycle
 Task Performance
 Infradian >24 hrs
 Lunar cycle
 Menstrual cycle
M
Sleep &
Chronophysiology
Laboratory
Circadian Rhythms
 24 hr rhythms in biology, physiology, mood &
performance that are entrained to the light dark
cycle
 Controlled by the SCN in the hypothalamus
 Light is the most potent zeitgeber
 Sleep, Cardiovascular Activity, Body Temperature,
Hormones, Endocrine & Metabolic Function,
Liver & Kidney Function,
Gastrointestinal Activity, Immunology
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Sleep &
Chronophysiology
Laboratory
0
EPOC
HS
900
800
700
600
100
900
800
700
600
500
400
300
200
% Time-In-Frequency
100
500
400
300
200
100
EPOCHS
100
% Time-In-Frequency
HIGH COHERENCE
.99
C3
C4
0
LOW COHERENCE
.43
Coherence in Girls at High-Risk
1
0.8
0.6
CUTPOINT= .70
0.4
0.2
HIGH RISK
>50 % of girls with extreme low
values had 1st episode 3-5 yrs later
NC
M
Sleep &
Chronophysiology
Laboratory
How Do We Improve Sleep &
Depression In College Students?





Education about Sleep
Education about Depression
Clearly identify Biological & Familial Risks
Early Intervention
Development of Easy,
Practical Guidelines for
Good Sleep Hygiene
M
Sleep &
Chronophysiology
Laboratory
Good Sleep & Biological Rhythm
Hygiene
 Maintain regular rise & bed times every night
including weekends i.e. 11:00 P.M.-6:00 A.M.
ESPECIALLY FOR WOMEN
 Very hot bath (~15 min. Duration) 1 1/2 hour before
bedtime ESPECIALLY FOR SWS PROBLEMS
 Turn down thermostat, no electric blankets Use very
dark curtains or use a sleep mask
 No napping especially in afternoon
or evening
M
Sleep &
Chronophysiology
Laboratory
Good Sleep & Biological Rhythm Hygiene
Restrict caffeine (not just coffee) 1-2 cups before 10
a.m.
Warm milk 1/2 hour before bedtime
No food or exercise within 2 hrs of bedtime
Avoid time zone changes
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Sleep &
Chronophysiology
Laboratory
Schedule for Light Exposure
• Early morning bright light will advance the circadian
clock i.e make you sleepy earlier
• Late afternoon bright light will delay your body clock
i.e make you sleepy later
• Wear dark glasses to minimize light to retina if your
body clock is already shifted
• Avoid bright light at night, use
incandescent light with the
lowest wattage possible.
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Sleep &
Chronophysiology
Laboratory
M
Sleep &
Chronophysiology
Laboratory