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http://dx.doi.org/10.2147/NSS.S62907

Causes and consequences of sleepiness among college students

Shelley D Hershner Ronald D Chervin Department of Neurology, University of Michigan, Ann Arbor, Mi, USA

Correspondence: Shelley D Hershner Department of Neurology, University of Michigan, Med inn C728, 1500 east Medical Center Drive, Ann Arbor, Mi, USA Tel +1 734 936 6295 Fax +1 734 647 9065 email [email protected]

Abstract: Daytime sleepiness, sleep deprivation, and irregular sleep schedules are highly prevalent among college students, as 50% report daytime sleepiness and 70% attain insufficient

sleep. The consequences of sleep deprivation and daytime sleepiness are especially problematic

to college students and can result in lower grade point averages, increased risk of academic

failure, compromised learning, impaired mood, and increased risk of motor vehicle accidents.

This article reviews the current prevalence of sleepiness and sleep deprivation among college

students, contributing factors for sleep deprivation, and the role of sleep in learning and memory.

The impact of sleep and sleep disorders on academics, grade point average, driving, and mood

will be examined. Most importantly, effective and viable interventions to decrease sleepiness

and sleep deprivation through sleep education classes, online programs, encouragement of naps,

and adjustment of class time will be reviewed. This paper highlights that addressing sleep issues,

which are not often considered as a risk factor for depression and academic failure, should be

encouraged. Promotion of university and college policies and class schedules that encourage

healthy and adequate sleep could have a significant impact on the sleep, learning, and health of

college students. Future research to investigate effective and feasible interventions, which dis-

seminate both sleep knowledge and encouragement of healthy sleep habits to college students

in a time and cost effective manner, is a priority.

Keywords: grade point average, GPA, sleep deprivation, academic performance, adolescence, sleep education programs

Introduction The college experience is of great value in providing emerging adults with a structured

environment in which they can gain the knowledge, skills, and independence to chart

their own path, become successfully employed, and contribute to society. However,

this experience comes at great cost given rising tuition fees and ballooning student

debt, and thus, it is vital that the college years be as efficacious as possible. A potential

obstacle to maximizing success in college is the high prevalence of daytime sleepiness,

sleep deprivation, and irregular sleep schedules among college students.

Daytime sleepiness is a major problem, exhibited by 50% of college students

compared to 36% of adolescents and adults.1 At least 3 days a week, 60% of students

report that they are dragging, tired, or sleepy.2 Sleepiness is defined as the inability or

difficulty in maintaining alertness during the major wake period of the day, resulting

in unintended lapses into drowsiness or sleep.3 It is important to note that sleepiness

is often circumstance-dependent, with many aspects of the students’ learning envi-

ronment exacerbating sleepiness.4 For example, a lecture that does not require active

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participation and may be in a dark, warm lecture hall can

unmask underlying sleepiness. Sleep deprivation is defined

as obtaining inadequate sleep to support adequate daytime

alertness.4 How much sleep a young adult needs is not clearly

known, but is thought to be 8 hours.5,6 Most college students

are sleep deprived, as 70.6% of students report obtaining less

than 8 hours of sleep.7 The impact of educational major on

sleepiness and sleep duration is not well studied, but the effect

may be substantial. As reported at an Architecture School in

the Midwest, only 4% of students obtained at least 7 hours

of sleep at night; the average sleep duration was 5.7 hours,

with 2.7 “all-nighters” per month.8 Eighty-two percent of

college students believe that inadequate sleep and sleepiness

impact their school performance.9 Students rank sleep prob-

lems second only to stress in factors that negatively impact

academic performance.10

Sleep deprivation and sleepiness are caused by a host of

reasons and have numerous negative consequences. In the

literature, sleep deprivation is often termed either acute sleep

deprivation or chronic partial sleep deprivation. Colloquially

for students, acute sleep deprivation is termed “pulling an

all-nighter”, meaning that a person stays up for 24 hours or

longer. More typically, sleep deprivation consists of chronic

partial sleep deprivation, where a student obtains some, but

not adequate sleep. Sleepiness can be an obvious conse-

quence of sleep deprivation, but sleepiness can be caused

by other circumstances, most commonly sleep disorders.

To understand the consequences of sleepiness and sleep

deprivation, knowledge of normal sleep and its impact on

learning, memory, and performance are necessary. Equally

important are potential interventions, as these may offer an

opportunity to improve health and educational outcomes

for this demographic. This article reviews the prevalence of

sleepiness and sleep deprivation among college students, the

impact of sleep on memory, contributing factors for sleep

deprivation, potential consequences with a focus on those

particularly applicable to college students, and available

interventions to improve sleep among college students.

Regulation of normal sleep: the circadian rhythm and homeostatic sleep drive Many college students are sleep deprived because they go

to sleep late and wake up for classes or employment before

adequate sleep is obtained. Two primary processes govern

how much sleep is obtained, the homeostatic sleep drive and

the circadian rhythm. The circadian system (internal clock)

helps to regulate sleep/wake cycles and hormonal secretions

while the homeostatic sleep drive increases the need for sleep

as the period of wakefulness lengthens. The interaction of these

two systems is described by the Two-Process Model of Sleep

Regulation.11

Physiologically, adolescents and young adults tend to have

a delayed circadian preference, and are “night owls”.12 This

change occurs in association with puberty; more physically

mature adolescents have a preference for later bedtimes and

may have a lower homeostatic sleep drive, and consequently,

are less sleepy at night.13–15 The typical adult circadian period

is 24.1 hours, compared to an adolescent’s circadian period of

24.27 hours; this longer period makes it easier for the bedtime

to shift later.15,16 A cardinal sign of a delayed circadian system

is an irregular sleep schedule, where students have catch-up

sleep on the weekend. Both high school and college students

demonstrate a 1–3 hour sleep deficit on school nights, with

a much longer sleep duration and often a later wake time on

the weekends.7,17,18

How the circadian rhythm and homeostatic sleep drive

change with puberty is not well understood, but the cumula-

tive effect is that adolescents and young adults feel more

awake in the evening, have a difficult time falling asleep until

later, and consequently, have insufficient sleep during the

school week and catch-up on sleep on the weekend.

Exactly when this nocturnal preference or “night owl”

tendency diminishes, remains unclear. When evaluated

longitudinally, weekday bedtimes continued to delay until

around 19 years of age, with weekend bedtimes remaining

later until the early 20s, although other studies have shown

this delay persisting until the junior year.19 The transition from

high school to college also has an impact; college students

go to bed 75 minutes later than high school students.7 In this

study, freshman students’ bedtime was 12.22 am and 1.58

am with a rise time of 8.08 am and 10.26 am on weekdays

and the weekend, respectively.

Learning, memory, and sleep cycles Sleepiness and irregular sleep schedules have many unin-

tended consequences, one of which is to negatively impact

learning, memory, and performance. The precise details of

the relationship between sleep and memory formation are

not yet completely understood. The dual process theory

maintains that certain types of memory are dependent on

specific sleep states, such that procedural memory (know-

ing how) may be dependent on REM (rapid eye movement)

sleep and declarative memory (knowing what) on NREM

(non-REM) sleep. The sequential processing theory suggests

that memories require an orderly succession of sleep stages,

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Sleep deprivation, sleepiness during college

ie, memory formation may be prompted by slow-wave sleep

and consolidated by REM sleep (see Figure 1).20

Both theories may help to explain how a student’s sleep

pattern could impact learning.21 In one study, REM sleep

deprivation eliminated sleep-induced improvement on a

visual perceptual learning (procedural) task; the same effect

was not found with selective slow-wave sleep deprivation.22

REM sleep normally occurs every 90–120 minutes,

approximately 4–5 times in a typical night, with each REM

sleep period growing progressively longer, with the last

episode near rise time.23 Therefore, college students with

early morning classes may not attain the last 1–2 REM

sleep periods, thus adversely affecting procedural memory.

However, other studies suggest that NREM rather than REM

sleep enhances procedural memories, while other studies

correlated improvement with slow-wave sleep followed by

REM sleep.24–26 Both of these theories support that sleep

deprivation may limit the amount of REM sleep and/or slow-

wave sleep that students obtain, which may compromise

both learning and memory, but further research is required

to clarify this.

Many studies investigating the interaction of sleep,

memory, and learning use scenarios of a specific memory task

and then alter subjects’ sleep pattern or duration to determine

the impact that sleep had on the subject’s performance. These

scenarios often may not directly correlate with the memory

and learning that college students are expected to perform or

the alterations in their sleep schedule they experience. Despite

these limitations, these studies illuminate the impact of

sleep on students’ memory, learning, and potential academic

performance.

Some students may “pull an all-nighter” (24 hours or

more of sleep deprivation) before examinations in the hope

of improved grades. The literature suggests that all-night

study sessions are the wrong plan for improved grades and

learning. Subjects were taught a visual discrimination task to

identify the presence of “T” or “L” and the orientation of three

diagonal bars on a screen. Subjects who were sleep deprived

for 30 hours showed no improvement in performance, even

after 2 days of post-recovery sleep.26 Non-sleep-deprived

subjects’ performance improved for the next 4 days. In

another study investigating if improvement correlated with

time or time spent in sleep, subjects were taught a motor

task and then tested either after a 12-hour period of wake-

fulness or a 12-hour period that included sleep.24 Subjects

tested at 10 am and then retested at 10 pm without sleep

showed no significant change in performance. After a night

of sleep, subjects’ performance improved by 18%. Subjects

tested at 10 pm initially, then retested after sleep, also had a

significant improvement in performance. This supports the

concept that sleep, and not just time, is required for learning

and memory consolidation. It may be possible that there is

a window for potential learning that requires sleep, and that

this opportunity for learning may not be salvaged even after

sleep is recovered.

Sleep before learning may also be necessary. To investi-

gate this concept, subjects were tested on an episodic memory

encoding task, which involved viewing a series of images

with a recognition test 48 hours later.27 Subjects were tested

after 35 hours of sleep deprivation; memory performance was

approximately two letter grades (19%; P=0.031) worse when compared to the non-sleep-deprived subjects. This difference

did not seem to be due to alertness, as there was no significant

difference between the two groups in terms of response rate,

which has been correlated with alertness.

Looking at more global functions, total sleep deprivation

showed a significant decrease of performance in cognitive

tasks assessing inference, recognition of assumptions, and

deduction.28 Although this study was not carried out on

college-aged students, subjects aged 10–14 years of age

restricted to 5 hours of sleep, had impaired performance on

verbal creativity and abstract thinking.29 Less complex cogni-

tive functions did not appear impaired; this has been shown

in other studies and may indicate that motivation, individual

response to sleep deprivation, or certain tasks may be less

impacted by sleep.20,30

Memory

Pattern of

sleep stages

Sleep stages

Figure 1 The interaction of sleep and memory. Notes: The dual process theory suggests that certain types of memory are dependent on specific sleep states, such as REM sleep, or slow-wave sleep (a stage of NReM sleep). The sequential processing theory suggests that memories require an orderly succession of sleep stages, eg, slow-wave sleep followed by REM sleep.20

Abbreviations: NReM, non-rapid eye movement; REM, rapid eye movement.

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Learning may also affect the intrinsic aspects of sleep.

Procedural tasks prior to sleep increased slow-wave activity

in the right parietal lobe, an area that is responsible for visual-

spatial skills.31 This increased right parietal activity correlated

with improvement in the task. Other studies have found an

increase in spindles, a defining feature of stage 2 sleep, after

procedural memory training.32 In an intensive 6-week French

language immersion course, improvement was correlated with

an increase in subjects’ percentage of REM sleep.33

In summary, these finding suggest that sleep, likely before

and after specific memory tasks, plays an integral part in

memory consolidation. Many of these studies isolate memory

into specific areas such as visual, declarative, or procedural;

however, college students’ learning, memory, and perfor-

mance in classes rarely would have such a narrow memory

domain. Further research with real-life circumstances of

students would better help clarify these important issues.

Causes of sleep deprivation and sleepiness Among college-aged students, one of the most common causes

of daytime sleepiness is sleep deprivation, ie, students get inad-

equate sleep because they go to bed late and wake up early. This

occurs for multiple reasons; some are physiologic and others

behavioral. The behavioral components may be particularly

problematic on college campuses. However, sleep deprivation

is not the only cause of sleepiness as college students are not

immune to sleep disorders, which may also cause sleepiness.

This section will review common causes of sleep deprivation

as well as the prevalence of sleep disorders among college

students, and the influence of sleep disorders on sleepiness.

Inadequate sleep hygiene Sleep deprivation can arise from poor sleep behaviors; sleep

hygiene encourages habits conducive to restorative sleep

and avoidance of substances or behaviors that are not. Good

sleep hygiene includes a regular sleep–wake schedule, quiet

sleep environment, and avoidance of caffeine after lunch and

stimulating activities before bed.34,35 Substances are not the

only aspect of inadequate sleep hygiene, as the ubiquitous

use of technology before bed may also adversely affect

sleep. Many students have inadequate sleep hygiene that, in

conjunction with their delayed circadian rhythm, encourages

sleep deprivation.

Alcohol Approximately four out of f ive college students drink

alcohol, with nearly 40% of men and women reporting

“binge drinking” at least 4–5 drinks in a row within the last

14 days.36,37 Alcohol shortens sleep latency, but then promotes

fragmented sleep in the latter half of the night.23 One study

found that 11.6% of students who drank used alcohol as a

sleep aid.7,38 Alcohol may also increase the risk for obstruc-

tive sleep apnea.39

Caffeine and energy drinks Caffeine, equivalent to 2–4 cups of coffee taken at

night, can increase sleep latency on average from 6.3 to

12.1 minutes, reduce sleepiness, and improve the ability to

sustain wakefulness.40 In this study, the effects of caffeine

lasted 5.5–7.5 hours, suggesting that caffeine consumed

even in the afternoon could impair the ability to fall asleep.

Caffeine is an adenosine receptor antagonist and can increase

arousal. Caffeine also may act on gamma-aminobutyric acid

neurons of the posterior hypothalamus to suppress sleep-

promoting pathways.23 The net effect is that caffeine increases

vigilance, alertness, and decreases sleepiness.

Energy drinks are becoming increasingly popular and

34% of 18–24-year-olds consume them regularly. In 2006,

Americans spent more than $3.2 billion on energy drinks.41

The majority (67%) of users consumed energy drinks to help

compensate for insufficient sleep.42 The contents of energy

drinks are variable and depend on the individual product,

but usually contain caffeine, herbal products, and sometimes

vitamins and other supplements. Caffeine is the primary

constituent responsible for the effect of increased energy.

The amount of caffeine varies widely from 45–500 mg. Use

of energy drinks is associated with higher use of alcohol and

possibly other drugs, including stimulants.43

Stimulants Use of either prescribed or nonprescribed stimulants is a

growing problem in young adults. The most commonly

reported reason is to “stay awake to study” or increase

concentration.44 Students may utilize these drugs more

than age-matched non-students.45 A survey at 119 col-

leges and universities across the US found a 6.9% lifetime

prevalence for the use of stimulants.46 Other studies show

prevalence as high as 14%.44,47 Men are more likely than

women to use stimulants, as well as caffeine and energy

drinks. Nonprescribed use of stimulants is associated with

increased use of alcohol, cocaine, and marijuana.46 Not all

stimulant use is illicit, as between 2%–8% of college students’

self-reported symptoms are consistent with attention deficit

hyperactivity disorder (ADHD).48 However, when parents of

college students were asked to report such symptoms in their

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children, the prevalence of ADHD decreased to around 1%.

Stimulants increase sleep latency and suppress REM sleep;

subjects who use stimulant medications report worse sleep

quality.23,47

Technology Inadequate sleep hygiene also encompasses the use of

technology prior to bed. Relevant data often must be

extrapolated from literature on adolescents, as few stud-

ies have focused on college students. The 2011 Sleep in

America Poll addressed technology available in the bedroom.

“Generation Y’ers” (adults aged 19–29 years old) are heavy

users of technology prior to bed: 67% use cell phones, 43%

music devices, 60% computers, and 18% video games. The

majority (51%) report rarely getting a good night’s sleep and

often wake unrefreshed. Computer use in the hour before bed

is associated with less restful sleep, higher Epworth Sleepi-

ness Scales, and drowsy driving.49 Frequent use of cell phones

around bedtime is associated with difficulties falling asleep,

repeated awakenings, or waking up too early.50 Most young

adults (57%) leave their phone on during sleep, with only

33% turning it to silent or vibrate modes (Table 1). Playing

video games before bed can increase sleep latency, an average

of 21.6 minutes.51 Functional magnetic resonance imaging

(fMRI) shows that video game playing heightens cognitive

alertness, especially during violent scenes (Table 1).52

Light exposure from various sources, including

computers, tablet computers (eg, iPads; Apple Inc., Cuper-

tino, CA, USA), and cell phones may also impact sleep.

Melatonin, secreted by the pineal gland, helps regulate the

circadian rhythm to the environment.15 Normally, it is low or

absent during the day and starts to rise about 2 hours before

the habitual bedtime. Melatonin is suppressed by light, and

light sources as low 200–300 lux (room lights) can cause

suppression.53 The amount of light from technologic devices

is variable; for example, a tablet computer generated 50 lux

suppressed melatonin in a cohort of college students after

2 hours of use.54 A case report describes a student in Brazil

who had a 40-minute delay in sleep on the weekends when

electric lights were installed.55 Bright light (8,000 lux) given

at 7 pm or at 9 pm reduced nighttime sleepiness in students

who had an evening preference and those with a later onset

of melatonin.56 One of the effects of technology may be to

suppress melatonin, resulting in a delay in sleep onset.

In summary, many students engage in behaviors, such

as those described above, which increase stimulation and

alertness prior to bed. This, in conjunction with their delayed

circadian rhythm, encourages late bedtimes and insufficient

sleep. To combat sleepiness, students often drink caffeine and

energy drinks, compromising sleep and ensuring a vicious

cycle of sleep deprivation (Table 2).

Sleep disorders Sleep deprivation is not the only cause of sleepiness on

campus, as sleep disorders may also play a role. A survey

of 1,845 students in introductory psychology labs suggested

that 27% were at risk for at least one sleep disorder or sleep-

related problem, including obstructive sleep apnea (4%),

insomnia (12%), restless legs disorder and periodic limb

movement disorder (8%), circadian rhythm sleep disorders

(7%), and hypersomnia (4%).57

Obstructive sleep apnea can be associated with significant

sleepiness.58 The prevalence of snoring may be more com-

mon than expected, as 30% of non-overweight students in

a California school reported snoring. Men more commonly

reported snoring (42%) than women (25%).59 Asian students

(37%) more often reported snoring than African-American

(24%) or Caucasian (27%) students. Although such obser-

vations of snoring frequency do not reveal the prevalence

of obstructive sleep apnea among college students, they do

Table 1 Frequent use of technology before bed is associated with sleep difficulties and daytime sleepiness

Use of cell phone in the bedroom was associated with a higher frequency of

• Daytime sleepiness • Poor quality sleep • waking unrefreshed • More difficulties falling

asleep and staying asleep • Repeated awakenings

Use of the computer before bed was associated with a higher frequency of

• Drowsy driving • Daytime sleepiness • Less restful sleep

Use of video games before bed was associated with a higher frequency of

• increased sleep latency

Note: Data from National Sleep Foundation;49 Dworak et al.51

Table 2 Challenges to good sleep hygiene in college students

Technology Tv, computer, or video games before bed Cell phones on overnight Frequent exposure to light before bed Substances Caffeine and energy drinks Alcohol use Stimulant use College scheduling and activities variable class schedules from day to day Late night socializing early or late obligations

Note: Data from.41,43,47,49,54

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suggest that this disorder may not be as infrequent among

young, otherwise healthy college students as is sometimes

assumed.

Consequences of sleep deprivation and sleepiness College is a time of intellectual growth and development

as young adults’ transition from adolescence to adulthood.

Although the worth of college in terms of increased produc-

tivity and higher earning potential is rarely debated, there is a

significant personal and societal cost of college both in terms

of time and money. For optimal return on the investment of

time, effort, and money, students need to maximize their

learning, academic, and personal growth. Sleepiness from

any cause can compromise these goals, through impact on

learning, memory, grades, perception of effort, driving per-

formance, and mood. Although sleep deprivation has effects

on many aspects of health, this article will focus on areas that

may be particularly problematic for college students.

Grade point average (GPA) and academic performance Despite growing evidence of the relationships between

sleep, learning, and memory, a direct connection between

learning and GPA has not yet been established.60 A stu-

dent’s GPA is not just an indication of learning, but instead

involves a complex interaction between the student and

their environment.61 Intelligence, motivation, work ethic,

personality, socioeconomic status, health problems, current

and past school systems, course load, academic program, and

test-taking abilities all may influence GPA.

Existing evidence does suggest an association between

sleep and GPA. Students who obtained more sleep

(long sleepers, $9 hours) had higher GPAs than short

sleepers (#6 hours): GPAs were 3.24 vs 2.74 on average,

respectively.62 More evidence exists to support an influ-

ence of sleep patterns rather than sleep duration on GPA.

Students at a community college near Washington DC

showed no difference in total sleep time (TST), sleepiness,

or morning preference between high (GPA .3.5) and low

(GPA ,2.7) academic performers.63 High academic perform-

ers instead showed earlier bed and rise times, though with

similar overall TST. No difference was present between

the two groups with regards to a morning preference, but a

validated questionnaire was not used.

Among first-year university students, sleep patterns also

influenced GPA; each hour delay in weekday or weekend

rise time decreased the GPA by 0.132/4.0 and 0.115/4.0,

respectively.60 Bedtimes were also influential, with later

bedtimes associated with lower GPAs. TST or circadian fac-

tors were not evaluated. These results do not explain why an

earlier rise time was associated with better grades; it could

arise from the sleep schedule itself, but many potential con-

founders exist. For example, early risers may also be more

motivated or organized. Another possibility is that negative

influences arise when students who have a nocturnal prefer-

ence are unable to wake up earlier. In a study of medical

students, subjects with an evening preference on the Horne–

Ostberg Questionnaire had a more irregular sleep pattern than

students with a morning or indifferent-type preference. Sleep

duration was not different between the groups, but subjects

with a more irregular sleep pattern had lower academic

performance.64 This suggests that sleep patterns influence

academic performance more than sleep duration, with the

caveat that students who have an evening preference may

have a more irregular sleep schedule.

Extreme forms of irregular sleep schedules include all-

night study sessions. No literature appears to address the

association between all-nighter study sessions and GPA, but

the absence of sleep is known to affect learning and perfor-

mance improvement. Subjects taught a visual discrimination

task who were then sleep deprived for 30 hours showed no

improvement in the task, even after 2 days of post-recovery

sleep.26 Non-sleep-deprived subjects’ performance improved

for the next 4 days. Similar results were demonstrated with

a finger-tapping motor task; without sleep, no significant

improvement occurred.24 All-nighter study sessions may also

alter motivation and perceived effort. Students’ self-perceived

effort and performance were evaluated following two sleep

scenarios: 24 hours of sleep deprivation or 8 hours of sleep.28

Despite performing worse, sleep-deprived subjects felt they

had better concentration, effort, and performance than did

non-sleep-deprived subjects. Why sleep-deprived subjects

rated their effort as higher is not known, and could be due to

sleep deprivation itself, or relate to other unknown factors.

This perception of improved performance following sleep

deprivation may in part explain why it can be challenging

to get students to change their sleep behavior. If students

perceive no impairment in performance due to lack of sleep,

they have little motivation to change.

Sleep disorders and academic performance Students with sleep disorders probably do not achieve optimal

academic performance, and up to 27% of students may be

at risk for at least one sleep disorder.57 Students at risk for

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Sleep deprivation, sleepiness during college

academic failure (GPA ,2.0) were at a disproportionately

high risk for sleep disorders. Among those who screened

positive for obstructive sleep apnea, 30% were at risk for aca-

demic failure. Medical students classified as frequent snorers

more frequently failed their Internal Medicine examination

(47%) than did occasional snorers (22.2%) or non-snorers

(12.8%). After adjustment for age, BMI, and sex, the rela-

tive risk for snorers to fail the examination was 1.26 (95%

confidence interval: 1.01–1.57).65 Obstructive sleep apnea

is suspected to have cognitive effects in both children and

adults.66 A higher percentage of students at risk for academic

failure screened positive for other sleep disorders including:

periodic limb movement disorder/restless legs syndrome

(21%),67 insomnia (22%), circadian rhythm sleep disorders

(26%), and hypersomnia (21%).57 As nearly one in four

students is at risk for a sleep disorder, screening for sleep

disorders among students with poor academic performance

may well be advisable.

Although many students have a nocturnal preference,

this preference can progress to delayed sleep-phase disorder

(DSPD), a circadian rhythm disorder characterized by sleep-

onset insomnia and difficulty waking at the desired time.3

Consequences of DSPD may include missed morning classes,

increased sleepiness, and decreased concentration, especially

in morning classes. Students with DSPD have lower grades.68

The prevalence of DSPD in the US college population may

be as high as 6.7%–17%.68,69

Driving One of the most concerning consequences of sleep depriva-

tion and sleepiness is drowsy driving. In the 2011 Sleep

in America Poll, 66% of young adults reported drowsy

driving.49 However, few studies have evaluated drowsy

driving specifically in college students. Among 1,039

undergraduate students, 16% reported falling asleep while

driving and 2% had had a motor vehicle accident due to

sleepiness. Men were more likely to fall asleep while driving

than women.38 A school in Utah had 86 student deaths due

to motor vehicle accidents over a 15-year period; dozing/

sleepiness was thought to be causative in 44%–72% of

the cases. In a retrospective review of students’ “clos-

est calls” for a motor vehicle accident due to sleepiness,

most near accidents occurred between 11 pm and 1 am

and often (39%) during the first hour of driving. Nearly

half (48%) of students had a less intense dozing episode

earlier in the same drive, with 68% of students continuing

their drive despite feeling sleepy.70 The findings overall

suggest that drowsy driving accidents or near accidents are

too frequent and that students may minimize the warning

signs of drowsiness.

Driving, sleep deprivation, and alcohol The impact of sustained wakefulness on driving performance

has been compared to the impairment of performance that is

produced by specific blood alcohol levels. In adults, sustained

wakefulness of 17 hours was equivalent to a blood alcohol

concentration (BAC) of 0.05%, and 24 hours was equivalent

to 0.1%, above the legal level for intoxication in the US and

most countries worldwide.71,72 Similar findings were found in

males aged 19–35 years of age, in whom 18.5 and 21 hours

of wakefulness produced changes in driving performance

mimicking a 0.08% BAC.73 Sleep deprivation in combination

with alcohol has a synergistic detrimental effect on driving

performance. To evaluate these effects, young male college

students were sleep restricted to 4 hours in bed; they then

consumed alcohol until they attained BACs of 0.025 g/dL

or 0.035 g/dL, equivalent to about 1–2 drinks.74 A simulated

driving task at 2 pm monitored crashes, speed variability,

and lane deviations. Crashes occurred in 23% and 33% of

the subjects (BAC 0.025 g/dL and 0.035 g/dL, respectively),

compared to only 4.7% in the controls and 19% in sleep-

restricted subjects who had no alcohol.

Driving after drinking is commonplace during college, as

up to 34% of students reported driving after drinking within

the last 30 days.75 The combination of sleep deprivation

and drinking may be especially common at the end of the

semester, when sleep-deprived students celebrate the end

of exams with drinks before driving home for the holiday

break. The dangerous combination of sleep loss and alcohol

could impair driving performance even in students who are

not legally intoxicated.

Mood effects Depression and sleep are interrelated. A cardinal feature

of depression is disturbed sleep.76,77 Depression is common

during the college years: 14.8% of students report a diagnosis

of depression and an estimated 11% have suicidal ideation.78

Insufficient sleep can increase depressive symptoms. In a

study of female college students, sleep debt of 2 hours per

night and/or a bedtime after 2 am was associated with greater

depressive symptoms.79 Irregular sleep schedules have been

associated with greater depressive symptoms. Prolonged

sleep latency was associated with loss of pleasure, punish-

ment feelings, and self-dislike.80 Differences between sex

were apparent, as women went to bed earlier, slept longer, had

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80

Hershner and Chervin

more nocturnal awakenings, and reported more depressive

symptoms. However, when the sleep variable was removed

by deleting the question, “Have you experienced changes in

sleep?”, no significant difference in sex persisted, suggesting

the greater incidence of depression in college-aged women

may be due in part to the greater number of reported sleep

difficulties.80,81

Improving sleep may improve depressive symptoms.

Cognitive behavioral therapy for insomnia (CBT-I) admin-

istered via email to college students with poor sleep quality

produced greater improvement in depressive symptoms

than did an intervention focused on mood and stress

reduction.67 A study on college students without reported

sleepiness or depression found that sleep extension sig-

nificantly improved scores on the Profile of Mood States.82

Increased total sleep in teenagers has also been shown to

improve mood. When school start time was delayed by

30 minutes, fewer students rated themselves as “at least

somewhat unhappy or depressed”.83 As sleep may be a

modifiable risk factor for depression, further research

is needed on ways to improve sleep and sleep quality in

depressed subjects.

Complex relationships exist between suicide, mood dis-

orders, and sleep. Insomnia may be a risk factor for suicidal

ideation, suicide attempts, and death by suicide.84 Conflicting

results have been reported on whether both insomnia and

nightmares increase the risk of suicidal ideation.85,86 A con-

founder is that post-traumatic stress disorder (PTSD) may

account for these associations. A study among college stu-

dents found that insomnia and nightmares were independently

associated with suicidal ideation. However, after depression,

anxiety, and PTSD were taken into account, nightmares, but

not insomnia, retained an association with suicidal ideation.

The presence of nightmares in a student with depression may

be a warning sign of increased risk for suicidal ideation that

warrants further evaluation.87

Potential interventions While sleep deprivation, irregular sleep schedules and

sleepiness are highly prevalent among college students,

little information is available on effective ways for schools

to successfully disseminate information on the importance of

sleep and to potentially improve the sleep of their students. In

general, the few programs that have been tried are expensive,

time consuming, and available for only a limited number of

students. A recent review of sleep education programs for

children and adolescents found only twelve studies, of which

four were available only as abstracts.81

Educational programs Improved sleep hygiene, which is widely believed to be

beneficial, has been the focus of most educational programs

on sleep, although there is little published support. An

American Academy of Sleep Medicine Practice Parameter

concluded in 1999 that insufficient evidence exists to recom-

mend sleep hygiene as a single therapy or in combination

with other treatments.88 A study evaluating sleep hygiene

awareness and sleep hygiene practice found only a weak

association between knowledge and practice. However,

good sleep hygiene practice was strongly correlated with

good sleep quality.35 Adequate sleep knowledge does not

necessarily translate into practice. Many sleep hygiene

recommendations, such as a quiet environment and use of

the bedroom only for sleep, may be challenging in college

dormitories.

One educational campaign with a focus on sleep hygiene

included a “Go to Bed” poster, a 2-page “Snooze letter”, and

sleep educational information in the school newspaper. An

earlier bedtime, shorter sleep latency, longer sleep duration,

and improved sleep quality, as measured by the Pittsburg

Sleep Quality Index, was noted in 9% of students.89 Although

this intervention did not affect a large percentage of the stu-

dent population, it was relatively inexpensive and did produce

a measurable benefit (Table 3).

Sleep courses In another study, a two-credit, 18-week course included group

discussion, lectures, and self-evaluation. Topics included

circadian rhythms, sleep hygiene, muscle relaxation, and

public sleep education.90 Participants had improved sleep

quality over the semester and women reported decreased

nap time. However, despite this intensive intervention, only

a limited effect on sleep patterns was observed.

The Sleep Treatment and Education Program (STEPS)

consisted of a 30-minute oral presentation and handouts

on various aspects of sleep, provided to students attend-

ing introductory psychology classes.91 Six weeks later,

participants showed improved sleep quality and sleep

Table 3 Components in sleep educational programs

“Snooze Letter” “Go to Bed” poster Sleep education information in school newspaper Two-credit course with discussion, lecture, self-assessment 30-minute oral presentation 8 weeks of emailed PDF addressing sleep schedule, relaxation, etc An extra credit online pre-test and self-education program

Note: Data from.67,89–91,93

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Sleep deprivation, sleepiness during college

hygiene. These results may be more robust than suggested,

as sleep quality and sleep behaviors typically worsen as the

semester progresses; therefore, this intervention not only

halted this deterioration, but resulted in improvement.92

Four supplementary sleep-learning modules, offered as extra

credit, improved sleep knowledge and encouraged some

sleep-related behavior changes, as 55% reported a change in

their sleep hygiene as compared to 45% of control students

(P,0.01).93 Students in the intervention reported specific

behavior changes such as having a more “consistent wake

time” versus a more general “trying to get more sleep” as

indicated by the control students. However, all of these

interventions are time consuming, involve only a select

number of students, and may not be practicable on a large

university scale.

Electronic cognitive behavioral therapy More feasible options are under development. A modi-

fied form of cognitive behavioral therapy for insomnia

(CBT-I) was emailed to students over an 8-week period.67

Each weekly email contained an attachment to address

several aspects of sleep, such as stabilizing the circadian

rhythm by anchoring wake time, relaxation techniques,

and a protocol for self-administered sleep restriction. This

was compared to an alternative program (Breathe), which

was created to reduce depressive symptoms and improve

coping skills for stress. Participants in the sleep program

(Refresh) had improvement in sleep quality and a decrease

in depressive symptoms. Although the study involved only

a small number (19 and 15, respectively), results showed

promise as an effective electronic program that could be

widely accessible and economically feasible for colleges

and universities.

Class scheduling The amount of sleep that students obtain is often dictated by

the first obligation of the day, typically their first class. This

is one reason why students often sleep longer and later on a

vacation or summer schedule.15 Therefore, class start times

are an opportunity for intervention, but available information

must be extrapolated from adolescent literature. A study at

an independent college preparatory school showed increased

sleep duration after a delay in school start time. The majority

of students were boarders (81.5%) with structured lights-out

schedules ranging from 10.30–11.30 pm.83 When school

was started at 8.30 am, 30 minutes later than usual, sleep

duration was increased by 45 minutes on school days. An

unexpected effect was that bedtime shifted earlier by 15

minutes. Following the time change, fewer students reported

daytime sleepiness (49.1% to 20.0%), sleepiness in class

(85.1% to 60.5%), and falling asleep in class (38% to 18%).

A positive effect on mood was found, with a decrease in

the Depressed Mood Scale.83 Students continued to have

significant “oversleeping” on the weekend, by nearly 3 hours.

A study of eighth graders (mean age 13.7 years) who had

1 hour of sleep extension for 5 days through delays in the

school start time, documented improved attention and perfor-

mance.94 This growing evidence from adolescents suggests

that later school start times do increase total sleep duration,

attention, and performance, but the data needs to be replicated

in college students (Table 4).

Naps Although not often considered as an intervention for sleep

deprivation, daytime naps may offer a potential remedy

that may also help academic performance. Interestingly, in

light of how napping may improve certain memory tasks,

high academic performers were more likely to nap than

low academic performers (52% vs 29%, respectively).63

In a study of non-sleep-deprived subjects, deterioration in

the performance of a visual perception task occurred dur-

ing the day.95 Intervening naps of 60 or 90 minutes halted

this deterioration, but only naps with both REM and slow-

wave sleep resulted in improvement compared to baseline.

Sustained wakefulness can impair performance. In an epi-

sodic memory-encoding task (face and name recognition),

significant deterioration at 6 pm occurred in all subjects,

except those who had had a 100-minute nap. In the nap

group, not only was performance deterioration abated, but

improvement was noted.27 Following training to recognize

phonetically similar words, subjects showed an increase in

accuracy, but 12 hours of sustained wakefulness reduced

improvements by half. A nap prevented this decrement in

performance.96,97 In short, naps may enhance certain cog-

nitive and performance tasks, but further research is still

needed in this important area.

Table 4 Potential interventions to reduce sleep deprivation and sleepiness

extracurricular educational programs Sleep courses Scheduling classes at a later start time, eg, 10 am classes encouraging naps via educational programs or availability of “nap rooms” Public health outreach programs to students Adequate evaluation and screening for sleep disorders

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Hershner and Chervin

Conclusion The college years are a time of critical transition from

adolescence to adulthood. For many individuals, this

transition is associated with inadequate sleep and daytime

sleepiness. Many factors contribute to this, including the

students’ own circadian physiology. Class times are often

scheduled without consideration of young adults’ circadian

patterns. Inadequate sleep hygiene is common, as students

often use technology and substances that compromise

sleep quality and quantity. This chronic sleep deprivation

may impair academic performance, mood regulation, and

driving safety. Students who attain sufficient sleep may still

struggle with sleepiness due to sleep disorders.

Further research is needed to not only determine how to

best educate students about the importance of sleep and the

consequences of sleep deprivation, but also how to translate this

knowledge into practice. Electronic or web-based interventions

may be economically feasible and attractive to an electroni-

cally savvy demographic. Universities and colleges need to

understand, acknowledge, and publicize that policies and class

schedules may have substantial impacts on the sleep, learning,

and health of their students. Investigation of new approaches

to promote good sleep and sleep habits could have significant

public health impact and should be prioritized.

Disclosure The authors report no conflicts of interest in this work.

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