Sleep Health: Module 2, Topic 2 Notes

Sleep Health

Introduction to Sleep Deficiency as a Public Health Problem

• Sleep deficiency is a critical public health concern due to its widespread impact on individual health and societal well-being.

• It affects numerous physiological and psychological functions, leading to significant adverse outcomes.

Personal Sleep Habits and Influences

• Individuals' typical sleep duration varies.

• Various factors can affect personal sleep, including lifestyle, stress, environment, and health conditions.

• Strategies to improve sleep often involve behavioral changes and environmental adjustments.

The Profound Importance of Sleep

• Humans spend approximately $\frac{1}{3}$ of their lives sleeping, highlighting its fundamental biological necessity.

• Brain Functions: The brain remains highly active during sleep, performing crucial functions such as memory consolidation, emotional regulation, and learning.

• Systemic Effects: Sleep profoundly impacts nearly every tissue and system in the body:

  • Brain: Essential for cognitive processes.

  • Heart: Influences cardiovascular health.

  • Lungs: Affects respiratory function.

  • Metabolism: Regulates energy balance and hormone production.

  • Immune function: Strengthens disease resistance.

• Adverse Effects of Lack of Sleep:

  • Acute Effects (Short-term):

    • Daytime sleepiness.

    • Irritability.

    • Fatigue.

    • Lack of concentration.

  • Chronic Effects (Long-term):

    • Increased risk of obesity.

    • High blood pressure.

    • Cardiovascular diseases (CVD).

Understanding Sleep Stages

• There are two main types of sleep: Non-REM (Non-Rapid Eye Movement) and REM (Rapid Eye Movement) sleep.

Non-REM Sleep

• Comprises three distinct stages:

  • Stage 1 (Light Sleep):

    • Characterized by light sleep, where an individual is easily awakened.

    • Muscles relax, occasionally accompanied by twitches.

  • Stage 2 (Transitional Sleep):

    • Eye movement stops.

    • Brain waves slow down, interspersed with occasional bursts of rapid brain waves.

  • Stage 3 (Deep Sleep):

    • Occurs primarily in the first half of the night.

    • Considered deep sleep, making it difficult to awaken the individual.

    • Brain produces large, slow delta waves.

    • Heart and respiratory rates are slow.

    • Muscles are fully relaxed.

  • Note: Some sleep stage descriptions may include four Non-REM stages, but for educational purposes in this context, Stages 3 and 4 are often grouped as deep sleep due to similarities.

REM Sleep

• Typically first occurs approximately $90$ minutes after falling asleep.

• Longer and deeper periods of REM sleep occur in the second half of the night.

• As the night progresses, the duration of REM sleep periods increases, while Stage 3 sleep duration decreases.

• Cycles along with Non-REM sleep throughout the night.

• Physiological Characteristics:

  • Eyes move rapidly behind closed eyelids.

  • Breathing, heart rate, and blood pressure become irregular.

  • Dreaming prominently occurs during this stage.

  • Arm and leg muscles are temporarily paralyzed, a protective mechanism to prevent acting out dreams.

The Sleep Cycle

• The entire sleep cycle, encompassing Non-REM and REM stages, typically lasts about $90-110$ minutes.

• A typical sleep cycle starts with Stage 1, progresses to Stage 2, then Stage 3, and finally enters REM sleep. This cycle repeats multiple times throughout the night, with the proportions of each stage shifting.

  • The deeper stages (Stage 3) are more prominent early in the night.

  • REM sleep duration increases in later cycles.

• Interference with this natural cycle (e.g., from certain medications) can lead to feeling worse the next day.

Recommended Sleep Duration by Age

• The amount of sleep needed per night varies significantly with age:

  • Newborns (0-2 months): $12-18$ hours.

  • Infants (3-11 months): $14-15$ hours.

  • Toddlers (1-3 years): $12-14$ hours.

  • Preschoolers (3-5 years): $11-13$ hours.

  • School-age children (5-10 years): $10-11$ hours.

  • Teens (10-17 years): $8.5-9.25$ hours.

  • Adults: $7-9$ hours.

Sleep Aids

• Approximately $8\%$ of U.S. adults report using sleep aids at least $4$ times per week.

• Sleep aids are generally categorized into three types:

Over-the-Counter (OTC) Sleep Aids

• Primarily contain antihistamines like diphenhydramine (e.g., Benadryl, Aleve PM) and doxylamine (e.g., Unisom).

• Side Effects:

  • Daytime drowsiness.

  • Blurred vision.

  • Dry mouth.

• Individuals can quickly build a tolerance to these medications, reducing their effectiveness.

• Not recommended for long-term use due to potential side effects and diminished efficacy.

Prescription Sleep Medications

• About $4\%$ of U.S. adults take prescription sleeping pills.

• Categories of Prescription Aids:

  • Hypnotics & Sedatives:

    • Increase the production of GABA, a neurotransmitter that induces drowsiness.

    • Examples include Benzodiazepines (e.g., Xanax), which are highly addictive and associated with severe withdrawal effects.

    • Z-drugs (e.g., Zolpidem/Ambien) are another class. Ambien is particularly associated with complex sleep behaviors, where individuals perform activities while not fully awake:

      • Sleep-driving.

      • Preparing and eating food.

      • Talking on the phone.

      • Sleep-walking.

  • Orexin Receptor Antagonists:

    • Work by blocking orexin, a neurotransmitter that promotes wakefulness, thereby promoting sleep.

  • Melatonin Receptor Agonists:

    • Mimic the effects of melatonin naturally produced by the body, helping to regulate the sleep-wake cycle.

• Off-label Use:

  • Some medications like antidepressants, anticonvulsants, and antipsychotics are sometimes used off-label to treat sleep issues due to their sedative properties.

Natural Aids

• Include substances such as melatonin, kava, and valerian.

• Important Note: These aids are generally not evaluated by the FDA for efficacy or safety due to their classification as supplements.