1. Sleep & Chronophysiology Laboratory
The Importance of Sleep and Sleep Hygiene: Practical Clues for the College Student
Dr. H. Lori Schnieders M
Sleep & Chronophysiology Laboratory

2. 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

3. OFF-LINE VISUAL SLEEP-STAGE
RAW DATA
STORAGE
DIGITIZED VALUES
AMPS
PSA or PAA
% ZERO-CROSS
% FIRST DERIVATIVE
POWER
A/D CONVERSION
BOARD RESIDENT
IN COMPUTER
SAMPLING RATE Hz
POWER
SPECTRA
BETA Hz*
SIGMA Hz
ALPHA Hz
THETA Hz
DELTA Hz
OFF-LINE VISUAL SLEEP-STAGE
SCORING
*FREQUENCY BAND WIDTHS DIFFER BETWEEN LABORATORIES

4. REM

5. Stage 4

6. HEALTHY NORMAL CONTROL
Awake
Move
REM
Stg 1
Stg 2
Stg 3
Stg 4
SOS: 23:54:00
TIME OF NIGHT
WUT: 08:51:30
% REM:
% STAGE 1:
% STAGE 2:
% STAGE 3:
% STAGE 4:
SLEEP EFFICIENCY: 96.8%
REM LATENCY: min
SLEEP LATENCY: min

7. 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

8. 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

9. How Has Sleep Changed Historically?
Estimated 8-9 hrs in early 20th Century
7-8 hrs mid 1980s-2002
College Students:
1980s reported hrs
2002 reported hrs
Going to bed later is the culprit
Bedtime is 1-2 hrs later
than it was 25 yrs ago M
Sleep & Chronophysiology Laboratory

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. DEPRESSED PATIENT TIME OF NIGHT % REM: 16.9 SLEEP EFFICIENCY: 79.2%
Awake
Move
REM
Stg 1
Stg 2
Stg 3
Stg 4
SOS: 01:04:00
TIME OF NIGHT
WUT: 08:51:30
% REM:
% STAGE 1:
% STAGE 2:
% STAGE 3:
% STAGE 4:
SLEEP EFFICIENCY: 79.2%
REM LATENCY: min
SLEEP LATENCY: min

17. 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

18. 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 M
Sleep & Chronophysiology Laboratory

19. HIGH COHERENCE LOW COHERENCE .99 .43 C3 % Time-In-Frequency C4
100
.99 C3
% Time-In-Frequency C4
100
200
300
400
500
600
700
800
900
EPOCHS
LOW COHERENCE
100
.43
% Time-In-Frequency
100
200
300
400
500
600
700
800
900
EPOCHS

20. Coherence in Girls at High-Risk
CUTPOINT= .70 M
Sleep & Chronophysiology Laboratory
HIGH RISK NC
>50 % of girls with extreme low values had 1st episode 3-5 yrs later

21. 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

22. 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

23. 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 M
Sleep & Chronophysiology Laboratory

24. 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. M
Sleep & Chronophysiology Laboratory