Sleep Disorders: Understanding the Basics to Improve Your Sleep

Sleep plays a crucial role in maintaining both physical and mental well-being. However, many people struggle with sleep problems, impacting their quality of life. This article will provide knowledge about normal sleep, common sleep disorders, and essential tips for improving sleep.

1. What is sleep?

Sleep is a reversible behavioral state. It is controlled by two interacting physiological mechanisms:

• Circadian rhythm: This is the body’s natural cycle, lasting approximately 24 hours, regulating biological rhythms such as the sleep-wake cycle, body temperature, hormones, etc.

• Homeostatic process: This process involves the accumulation of “sleep debt” during wakefulness, leading to a stronger urge to sleep as wakefulness time extends.

2. Stages of Normal Sleep

Normal sleep consists of 4-5 cycles, each lasting 90-120 minutes, and each cycle is divided into different stages:

• Non-Rapid Eye Movement (NREM) Sleep: This includes 4 stages:

• Stage 1: Sleep onset, the transition from wakefulness to sleep, very brief (a few minutes), brain waves shift from alpha to theta waves.

• Stage 2: Light sleep, theta waves alternate with fast waves of 12-14Hz and K-complexes (two-phase high-voltage waves).

• Stage 3: Deep sleep, vital signs decrease, muscle tone decreases, slow delta waves with high voltage of 1,5-2Hz account for <50% of the time.

• Stage 4: Vital signs decrease the most, slow delta waves predominate.

• Note: Stages 3 and 4 are referred to as slow-wave sleep, crucial for bodily recovery, memory consolidation, and immune system enhancement.

• Rapid Eye Movement (REM) Sleep: Occurs about 70-90 minutes after stage 1, lasting approximately 10 minutes.

• Characteristics: Increased vital signs (heart rate, breathing, blood pressure, temperature), reduced gastrointestinal motility, decreased muscle tone, and rapid eye movements.

• Brain activity: Alpha brain waves similar to wakefulness, but very deep sleep.

3. Sleep in Older Adults

• Characteristics:

• Stage 1 and 2 prolonged (lighter sleep).

• Stage 3 and 4 reduced (deeper sleep), in individuals >90 years old, stages 3 and 4 may completely disappear.

• Increased awakenings during the night.

• Circadian rhythm: Shifts earlier than younger adults by 1-2 hours, leading to earlier bedtimes.

• Sleep duration:

• Increased time in bed.

• Mildly decreased total sleep time.

• Increased sleep latency.

• Increased awakenings after sleep onset.

• Decreased sleep efficiency.

• Daytime sleepiness.

4. Common Sleep Disorders

4.1 Insomnia:

• Definition: Difficulty initiating or maintaining sleep.

• Diagnostic criteria:

• Sleep latency >30 minutes.

• Sleep efficiency <85%.

• Note: Insomnia can be a symptom of many other medical conditions and requires appropriate diagnosis and treatment.

4.2 Obstructive Sleep Apnea (OSA):

• Definition: Episodes of upper airway obstruction, causing oxygen desaturation and awakenings.

• Risk factors:

• Male sex.

• Large neck circumference (>40cm).

• Obesity, ear, nose, and throat diseases, large tongue.

• Symptoms:

• Snoring.

• Episodes of apnea lasting about 10 seconds.

• Recurring about 5 times per hour.

• Restless sleep, daytime sleepiness.

• Note: OSA can lead to serious complications and requires timely diagnosis and treatment.

4.3 Periodic Limb Movements of Sleep (PLMS):

• Definition: Jerking movements lasting a few seconds, occurring periodically every 30 seconds, usually in the lower extremities.

• Always associated with toe extension and foot dorsiflexion.

• Often accompanied by Restless Leg Syndrome.

• Occurs during stages 1 and 2 of sleep.

• Note: PLMS can disrupt sleep, affecting sleep quality and overall health.

4.4 REM Sleep Behavior Disorder (SBD):

• >85% are male, onset between 50-60 years of age.

• Mechanism: Normally, REM sleep is accompanied by dreaming and muscle atonia; in SBD, muscle atonia is absent, the patient acts out their dreams (usually vivid).

• Causes: Parkinson’s disease, multiple system atrophy, medications.

• Note: SBD can be dangerous and requires timely diagnosis and treatment.

4.5 Restless Leg Syndrome (RLS):

• Symptoms: Unpleasant sensations like crawling, tingling, or burning in the lower extremities, intensified during rest and at night, relieved by movement.

• Associated with Periodic Limb Movements of Sleep: 80% of patients with RLS have PLMS, while 30% of those with PLMS have RLS.

• Note: RLS affects sleep quality and overall health, and requires appropriate treatment.

5. Tips for Improving Sleep

• Maintain a regular sleep-wake schedule.

• Develop a relaxing bedtime routine (warm bath, reading, listening to calming music).

• Avoid stimulants like coffee, alcohol before bed.

• Create a dark, quiet, and cool sleep environment.

• Engage in regular exercise, but avoid exercising too close to bedtime.

• Eat a healthy diet and avoid heavy meals before bed.

• Avoid long naps.

• Consult a doctor if you experience sleep problems.

6. Conclusion

Sleep is essential for overall health, quality of life, and work performance. Understanding normal sleep, common sleep disorders, and tips for improving sleep is crucial. Pay attention to your sleep to maintain your health and a fulfilling life.