Why is Sleepy so darn sleepy?:

Factors in Sleepiness

Adam J. Sorscher, MD

Assistant Professor of Family Medicine

Dartmouth Medical School

adam.sorscher@dartmouth.edu

Learning Objectives

• Describe consequences of insufficient sleep

• Review determinants of sleepiness

• Explore the controversy: how much sleep does an individual need?

The Iconic “Sleepy”

Some Public Health Consequences of Sleepiness

What is the function(s) of sleep? (or

what suffers with inadequate sleep?)

Short Term Physiologic Studies

• Lab settings, short-term sleep restriction leads to:

-- impaired glucose control

-- increased cortisol

-- increased blood pressure

-- sympathetic activation

-- increased CRP

Meier-Ewart HK, et al J Am Coll Cardiol 2004 43: 678-83

Pain. Author manuscript;

available in PMC 2009

July 1.

Published in final edited

form as:

Pain. 2008 July; 137(1):

202–207. Published online

2008 April 22. doi:

10.1016/j.pain.2008.01.02

5.

PMCID: PMC2527580

NIHMSID: NIHMS57072

Copyright notice and Disclaimer

Duration of Sleep Contributes to Next-Day Pain Report

in the General Population

Robert R. Edwards, Ph.D.,1 David M. Almeida, Ph.D.,2 Brendan Klick, ScM,1 Jennifer A.

Haythornthwaite, Ph.D.,1 and Michael T. Smith, Ph.D.1 1 Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of

Medicine 2 Department of Human Development and Family Studies, Pennsylvania State University,

State College

Address correspondence to: Robert R. Edwards, Ph.D., Department of Psychiatry &

Behavioral Sciences, Johns Hopkins University School of Medicine, 600 N. Wolfe St,

Meyer 1-108, Baltimore, MD 21287, Phone: 410-614-3396, Fax: 410-614-3366, Email:

redwar10@jhmi.edu

The publisher's final edited version of this article is available at Pain.

See other articles in PMC that cite the published article.

Publisher's Disclaimer

Hypothalamus = Homeostasis

Filthy Hands, Droopy Eyelids

Sleep and Sleepiness

• The right quality – OSA, PLMD, Nocturnal Sz disorder

• The right timing – circadian rhythm disorders

• The right duration – controversial!!

Could Sleepy Have a Circadian Rhythm Disorder?

11:00 pm off to bed!

Go to Work after Sunrise

Is Sleepy Overworked??? Sleep deprived??

The Low Countries: Belgium, Luxemborg, and Netherlands

Note the Footwear

Footwear Up Close

Slashed Sleeves and Collars

In his book Kühreichen oder Kühreigen: Yodeling and Yodeling Song in Appenzell (1890), the scholar Alfred Tobler reports that

the first documented reference to yodeling in Europe was as early as 1545.

How Much Sleep Do We Need?

“Nature needs five

Custom takes seven

Laziness takes nine

And wickedness eleven”

For myself I never found need of

more than four or five hours'

sleep in the twenty-four. I never

dream. It's real sleep. When by

chance I have taken more I

wake dull and indolent. We are

always hearing people talk

about "loss of sleep" as a

calamity. They better call it loss

of time, vitality and

opportunities.

…but he was a good napper

“Life is Short, Stay

Awake for It” – Caribou

Coffee Motto

HABITUAL SLEEP TIME IN US

NSF/Gallop Poll 2005:

Ave. adult = 6.8 hours on weekdays

(7.4 hours on weekends)

Rampant Sleep Deprivation?

Total Sleep Requirement

Are We Sleep Deprived?

Yes: Historical studies pre-Edison/self report surveys/MSLT studies in healthy young

men/ability to extend sleep

Vs.

No: MSLT overestimates hypersomnia/EDS may be due to comorbid conditions/ability to extend

sleep isn’t clinically meaningful (core sleep hypothesis)

Interindividual Variability:

Putative Traits

• Sleep requirement

• Vulnerability to sleep loss

• Sleep-ability

• Morningness/eveningness

• Rigidity to morningness/eveningness

• Sleep inertia

Subjective sleepiness/ performance disconnect

Concluding Remarks

• Sleep is crucial to multiple functions of the brain (including “HEAL”)

• Stimulants are not a substitute for sleep

• Multiple traits make it difficult to know how much sleep an individual needs, but most of us begin to do poorly at < 7 hours per 24 hr. cycle

Addendum:

The Sleeping Death