Sleep: A Biological Imperative and Public Health Priority

“Sleep… is a biological requirement for human life. We sleep for the same reason we breathe and drink. It’s an imperative. Yet we live in a society that devalues sleep.”
— Michael A. Grandner, PhD

Sleep is not a luxury—it is a fundamental biological necessity. Defined as a recurring, reversible state of perceptual disengagement, reduced consciousness, and relative immobility, sleep enables the brain and body to restore and maintain health (Grandner & Rosenberger, 2019).

The Foundations of Sleep

Sleep is essential across the lifespan. It involves complex interactions between neural circuits and endocrine signals. Adults generally require 7–9 hours of sleep every 24 hours to function optimally. After about 15–17 hours awake, the body builds an urge to sleep—a process driven by homeostatic mechanisms.

Insufficient sleep compromises every aspect of well-being:

  • Physically: Impairs cardiovascular, metabolic, and immune function.
  • Cognitively: Slows reaction time, reduces attention, and impairs memory.
  • Emotionally: Destabilizes mood and increases anxiety, depression, and irritability.

The Functions of Sleep

During sleep, the body engages in critical maintenance:

  • Reduces sympathetic nervous system arousal and activates parasympathetic recovery
  • Strengthens innate and adaptive immunity
  • Regulates inflammation via cytokine production during deep sleep
  • Repairs neuronal DNA and mitigates oxidative stress
  • Clears metabolic waste via cerebrospinal fluid “brain flush”
  • Consolidates memories and primes the brain for learning
  • Synchronizes circadian rhythms and regulates hunger hormones (ghrelin/leptin)

Sleep also enhances mood, creativity, decision-making, and physical resilience. Regular, adequate sleep has been linked to reduced risk of heart disease, stroke, obesity, and Alzheimer’s disease.

The Cost of Short-Term Sleep Restriction

Even short-term sleep restriction is harmful. “Like our physical well-being—mental and emotional health rely on a delicate balance,” says researcher Eti Ben Simon. “Even a single sleepless night can therefore do damage.”

  • After one night of sleep deprivation, cognitive and motor performance declines to levels comparable to a 0.10% blood alcohol concentration—worse than the U.S. legal driving limit of 0.08% (Dawson & Reid, 1997).
  • Blood pressure increases (Krause et al., 2023).
  • Prefrontal cortex activity drops, impairing executive functioning and emotional regulation (Ben Simon, 2023).

Short sleep duration is strongly correlated with worsening mental health. A study of healthy young adults by Ramsey, Grandner, & Verma (2019) found that each additional night of insufficient sleep increased:

  • Depressed mood by 21%
  • Hopelessness/anger by 24%
  • Anxiety/self-harm thoughts by 25%
  • Functional problems by 28%
  • Suicidal thoughts by 28%

Another study found that three nights of partial sleep deprivation (4.25 hrs/night) significantly increased inflammatory proteins in the blood—many of which are linked to a higher risk of cardiovascular diseases. These changes were observed in healthy young adults, highlighting that the negative effects of poor sleep can begin early and quickly. While physical exercise still triggered some beneficial protein responses regardless of sleep levels, the results showed that exercise cannot fully offset the harmful impact of inadequate sleep (Brandão, Zhang, Grip, et al., 2025).

Microsleeps are brief episodes of involuntary sleep (15 seconds or less) that can occur when sleep-deprived. Parts of the brain temporarily stop processing incoming information while the person is unaware that they have fallen asleep. These lapses significantly increase accident risk, including drowsy driving crashes, which cause an estimated 91,000 crashes, 50,000 injuries, and nearly 800 deaths each year (NHTSA).

Chronic Sleep Deprivation: Long-Term Risks

“Alertness in the brain, even under normal circumstances, carries with it penalties… if you ask your cells to stay active 30 percent longer each day, cells die.”
— Fabian Fernandez, PhD

Over time, partial sleep restriction leads to:

  • Cognitive decline and memory impairment
  • Hormonal dysregulation (e.g., reduced testosterone)
  • Increased risk of depression, anxiety, and suicidal ideation
  • Higher risk of metabolic disorders, cardiovascular disease, and certain cancers

A study of adults aged 50–70 found that sleeping 5 hours or less per night increased the risk of multimorbidity (two or more chronic diseases) by 30–40% (Sabia et al., 2022).

Diseases linked to chronic sleep restriction include:

  • Heart disease, stroke, and arrhythmias
  • Type 2 diabetes and insulin resistance
  • Alzheimer’s dementia and Parkinson’s dementia
  • Inflammation-linked cancers
  • Depression

A 15-year study (Cavailles et al., 2024) found that people reporting frequent sleep problems had brain aging equivalent to 2.6 years older, independent of other health factors.

Shift Work and Mortality

Long working hours and shift work compound sleep loss. In 2016, 745,000 deaths from stroke and ischemic heart disease were linked to long working hours—a 29% increase since 2000 (WHO & ILO).

Shift workers face increased risks of cancer, cardiovascular disease, mood disorders, and cognitive impairment due to disrupted melatonin production and circadian rhythm disruption.

The Myth of Catch-Up Sleep

“Catch-up sleep does not appear to be an effective strategy to reverse sleep loss-induced disruptions of metabolism.”
— Dr. Kenneth Wright, Jr.

Weekend recovery sleep may slightly reduce cardiovascular risk (Song, 2025), but it does not restore cognitive function or improve insulin resistance (NIH, 2019). Alarmingly, individuals may feel better after catching up on sleep while remaining cognitively impaired, dangerously misjudging their capabilities (Zamore & Veasey, 2022).

In animal studies, brain inflammation, neuronal death, and Alzheimer’s markers persisted long after sleep deprivation—possibly permanently (Zamore & Veasey, 2022).

For decades, researchers and practitioners have noted the reduced life expectancy of correctional and police officers (see FL paper), often attributing it anecdotally to chronic high-stress work environments. But what if this shortened lifespan—and even some suicides—are also linked to the chronic sleep deficits experienced by custody and security staff due to mandatory overtime and shift work?

Protecting Your Sleep and Health

The only true solution to sleep deficit harms is prevention—by ensuring regular, sufficient sleep.

What You Can Do:

  • Aim for 7–9 hours of sleep each day
  • Stick to consistent sleep and wake times—even on days off
  • Create a quiet, dark bedroom (use blackout curtains or eye masks)
  • Reserve the bed for sleep and sex only
  • Avoid alcohol, gaming, and screens before bedtime
  • Practice relaxation techniques before sleep
  • Consult a physician about safe sleep aids (some antidepressants may help)
  • Avoid habit-forming drugs like benzodiazepines or barbiturates
  • If you are considering non-prescription sleep aids, including herbal or other supplements, consult a medical provider to discuss potential side effects and interactions with any prescribed medications.

Other Health Strategies:

  • Monitor heart health: blood pressure, cholesterol, weight
  • Participate in workplace health screenings
  • Practice stress management (mindfulness, prayer, breathing exercises)
  • Maintain a healthy lifestyle:
    • Eat a balanced diet (fruits, vegetables, legumes, nuts, whole grains)
    • Stay physically active
    • Avoid smoking and limit alcohol intake
    • Cut caffeine at least 4 hours before bedtime

“Inevitably we all miss out on sleep from time to time. But our societies should critically examine structures—such as work norms—that prevent people from getting enough rest. The science of sleep and mental health suggests that failing to address those problems will leave people vulnerable to serious harm.”
— Eti Ben Simon, PhD