1. Sleep Deprivation and Sleep Cycles
By: Audrey Kettelberger

2. Brief History of the Study of Sleep
Our fascination with sleep dates all the way back to 450 BC with the Ancient Greeks, although there wasn’t much concrete science behind it until 1929
1929- Hans Berger develops an electroencephalograph device to record brain waves, and notes differences in brain activity during sleep and wakefulness
1937- Alfred Loomis, E. Newton Harvey and Garret Hobart identify five distinct stages ofsleep, using EEG traces
Since then, the study of sleep has made very significant discoveries and advancements

3. What is A Normal sleep cycle?
Three stages of non-REM sleep as known as N1, N2, N3
N1 generally occurs as you slowly nod off
N2 is signaled by sleep spindles and/or K complexes in the EEG
N3 is referred to as “slow-wave,” “delta,” or “deep” sleep
The longer NREM sleep progresses, less responsive the brain becomes to external stimuli (it gets more difficult to wake someone up)
1 to 7 minutes
10 to 25 minutes
20 to 40 minutes

4. What is A Normal sleep cycle?
Following the N3 stage, the body usually signals an "ascent" to lighter NREM sleep
There is typically a 5- to 10-minute period of N2 before entering REM sleep
REM comprises about 20 to 25 percent of total sleep in typical healthy adults.

5. How Much Sleep Do We Need?
The amount of sleep we need is determined by our age:
The older we get, the less sleep we require.

6. What Causes Us to Lose Sleep?
Undiagnosed sleep disorders are a major cause of sleep loss
There are more than 85 sleep disorders are recognized by the American Sleep Disorders Association
Up to one-third of Americans have symptoms of insomnia; however, less than 10% of those are diagnosed
Sleep-related breathing disorders represent a spectrum of abnormalities that range from simple snoring to sleep apnea
As highly prevalent as they are, most cases remain undiagnosed and untreated

7. What If we don’t Get Enough Sleep?
Short-Term Effects Include:
Reducing your nighttime sleep by as little as one and a half hours for just one night could result in a reduction of daytime alertness by as much as 32%
Memory and Cognitive Impairment (limits your ability to think and process information)
Inability to participate in certain activities that require sustained attention can lead to a poorer quality of life
Excessive sleepiness also contributes to a greater than twofold higher risk of sustaining an occupational injury
Each year drowsy driving is responsible for at least 100,000 automobile crashes, 71,000 injuries, and 1,550 fatalities.

8. What If we don’t get enough sleep?
Long-Term Effects:
High blood pressure
Heart attack
Heart failure
Stroke
Obesity
Depression and other mood disorders
Attention Deficit Disorder (ADD)
Mental impairment
Fetal and childhood growth retardation
Injury from accidents
Disruption of bed partner's sleep quality
Poor quality of life

9. What if we don’t get enough sleep?
Those who fail to sleep for the required amount of time acquire what is called a “sleep debt”
Sleep debt: The cumulative effect of not getting enough sleep
Example: Missing two hours of sleep a night for five consecutive nights results in ten hours of sleep debt
A large sleep debt may lead to mental or physical fatigue
Like with a credit card or a mortgage, sleep debt eventually has to be repaid

10. Sleep Debt; What can we do about it?
Catching up over the weekend is not the best strategy
Clean up your sleep habits to maximize the hours of snooze time during the week, even if it’s only a measly 15 extra minutes
Stick to a regular sleep and wake schedule, avoid caffeine and alcohol, exercise daily, and relax before bed
Avoid electronics before bed, as they can disrupt sleep
A daytime nap may also help you catch up, if it’s possible for you to take one regularly.

11. The best way to avoid the effects of sleep deprivation is to get a full night’s sleep every night. You must be aware of sleep debt and carefully monitor how much is accumulating. Keep your sleep debt manageable and sleep habits healthy in order to live life well- rested.