Rest to Recover: How sleep rebuilds mind and body

Vivian Kapil

Consultant Psychiatrist, Kauvery Hospital, Vadapalani, Chennai, Tamil Nadu

Introduction

Sleep is a fundamental biological process that occupies nearly one-third of our lives and is essential for our physical health, cognitive performance, and emotional wellbeing.

How Much Sleep Do We Need? (Varies by Age)

  • Newborns: 14–17 hr
  • Toddlers: 11–14 hr
  • Teenagers: 8–10 hr
  • Older Adults: 7–8 hr

If you wake up refreshed and stay alert throughout the day, you’re likely getting the right amount of sleep.

The Three Pillars of Wellbeing

  • Adequate Sleep
  • Balanced Nutrition
  • Regular Physical Activity

Why Sleep Matters

  • Learning: Improves the brain’s ability to absorb new information
  • Memory Consolidation: Strengthens and organizes memories
  • Smart Forgetting: Filters out unimportant memories, improving focus
  • Boosts immune cell activity- During deep sleep, the body produces and releases cytokines, a type of protein that fights infection and inflammation
  • Reduces Stress Hormones: Sleep lowers cortisol levels, a stress hormone that, when elevated chronically, can suppress immune function
  • Promotes Healing: Sleep helps repair tissues, regulate inflammation, and support overall immune surveillance

Stages of Sleep

Sleep is divided into two main types:

  1. Non-Rapid Eye Movement (NREM) Sleep- N1 (light sleep), N2, N3 (deep sleep)
  2. Rapid Eye Movement (REM) Sleep (dreaming occurs during this)

Each night, we cycle through these stages’ multiple times, with each cycle lasting around 90–110 minutes.

Typical Sleep Cycle Breakdown

  • 75–80%: NREM sleep
  • 20–25%: REM sleep

A healthy adult usually completes 4–6 cycles per night.

Causes of Sleep Problems

Lifestyle Factors

  • Stress, Worry, Anxiety
  • Bereavement, Trauma
  • Poor sleep environment or routine
  • Alcohol, Smoking, Substance use

Physical Health Conditions

  • Chronic Pain
  • Diabetes, Hypertension
  • Breathing difficulties
  • Obstructive Sleep Apnoea

Mental Health

  • Depression
  • Anxiety Disorders
  • PTSD
  • Other Psychiatric Conditions

Other Factors

  • Ageing
  • Menopause

Implications of Chronic Sleep Deprivation

Chronic sleep deprivation—defined as consistently getting less sleep than the body needs—can have wide-ranging effects on nearly every system in the body. Even mild but chronic sleep restriction can impair functioning to the same extent as total sleep deprivation.

Cognitive and Psychological Effects

  • Focus Issues: Difficulty concentrating
  • Irritability: Increased frustration
  • Slow Thinking: Sluggish mental processing
  • Delayed Reactions: Slower reflexes
  • Poor Judgment: Risky or irrational decisions
  • Impulsivity: Higher tendency for risky behavior
  • Confusion: Mental fog and disorientation
  • Impaired concentration, attention, and memory
  • Poor decision-making and problem-solving abilities
  • Increased risk-taking and impulsivity
  • Heightened risk of depression, anxiety, and mood disorders
  • Reduced ability to regulate emotions and cope with stress

Physical Health Consequences

  • Elevated risk of cardiovascular disease (hypertension, heart attacks)
  • Increased insulin resistance, leading to type 2 diabetes
  • Weight gain and obesity due to hormonal imbalances (ghrelin ↑, leptin ↓)
  • Suppressed immune function, making one more vulnerable to infections
  • Increased inflammation, linked to various chronic conditions

Long-Term Risks

  • Higher risk of stroke, Alzheimer’s disease, and other neurodegenerative disorders
  • Accelerated biological ageing
  • Reduced life expectancy

Daily Functioning and Safety

  • Microsleeps and fatigue-related accidents (e.g., driving or workplace errors)
  • Decreased productivity and work performance
  • Strained interpersonal relationships due to mood instability

Alcohol’s Effect on Sleep

  • Disrupts sleep in a dose-dependent manner
  • Delays REM sleep onset
  • Leads to fragmented REM sleep
  • Causes frequent awakenings
  • Increases light sleep (N1 stage)

Night Shift Sleep Strategies

  • Extend Sleep: Use naps and longer rest periods
  • Bright Lights: Improve alertness during shifts
  • Limit Shift Changes: Help regulate internal clock
  • Block Distractions: Create a quiet, dark sleep environment
  • Timed Caffeine Use: Early-shift use boosts alertness

Dos and Don’ts for Better Sleep

Dos

  • Keep a consistent sleep-wake schedule
  • Develop a bedtime routine to wind down
  • Engage in relaxing activities before bed
  • Include regular exercise in your routine
  • Maintain a comfortable, cool, and quiet bedroom

Don’ts

  • Don’t worry about sleep—it increases anxiety
  • Avoid using the bed for work or screens—associate it only with sleep and intimacy
  • Skip late-night caffeine—it can delay sleep
  • Don’t go to bed before you’re sleepy
  • Avoid long daytime naps—they disrupt nighttime sleep

Consider seeing a psychiatrist if you experience:

  • Difficulty falling or staying asleep for more than 3 nights a week, lasting over a month
  • Persistent early morning awakenings and inability to return to sleep
  • Excessive daytime sleepiness despite adequate sleep time
  • Dependence on sleeping pills, alcohol, or substances to initiate sleep
  • Sleep disturbances accompanied by low mood, anxiety, irritability, or emotional instability
  • Symptoms of insomnia, nightmares, or flashbacks following trauma
  • Sleep issues related to mental health disorders such as depression, anxiety, bipolar disorder, or psychosis
  • Unexplained fatigue, poor concentration, or memory lapses impacting work or relationships

Conclusion

“Good sleep is not a luxury, but a necessity for both physical and mental wellness. A good night’s sleep is the closest therapy you can get.”

Kauverian Bookshelf

Applied Medical Statistics

Journals

Kauvery Hospital
Find Doctor
Book Appointment