Sleep: Why it matters?

August 18, 2024, 12:57 PM IST Lalit Kapoor in FIVE PILLARS OF HEALTH: A Blueprint for Wellbeing, Health, Lifestyle, World, TOI

Nearly two out of three people in the U.S. don’t get sufficient sleep, significantly impacting their health. One-third of people sleep six hours or less, double the rate from 50 years ago. The CDC recognizes this as a public health epidemic, with an estimated 60 million Americans suffering from chronic sleep disorders. Children are progressively getting less sleep, averaging two hours less per night compared to a century ago. One in five car crashes in the U.S. is caused by drowsy driving. Here’s what we know about sleep:

Why do we sleep?

1. Brain maintenance:

The brain, which consumes 25% of the body’s energy, produces metabolic waste that must be removed. Cerebral spinal fluid flushes out waste like beta-amyloids during deep sleep. Accumulation of these wastes can lead to diseases like dementia and Alzheimer’s disease. Besides removing toxins during sleep the brain repairs brain cells, prunes connections, and transfers short-term memory into long-term memory. It also integrates daily learning, especially perceptual learning, with prior experiences.

2. Energy replenishment:

Sleep replenishes energy sources. Tiredness builds up Adenosine levels in the brain leading to involuntary sleep, which is dangerous while driving. Caffeine temporarily blocks this signal but does not prevent it.

3. Cognitive function:

Lack of sleep impairs concentration, logical thinking, memory, focus, attention, and alertness. It also triples reaction times, contributing to auto accidents.

4. Health impact:

Sleep affects the cardiovascular system, including heart function and blood pressure. Sleep deprivation is linked to high BP, weakened immune systems, increased infections, and cancer progression.

5. Appetite regulation:

Sleep deprivation disrupts appetite regulation, leading to overeating and increased obesity.

6. Increased insulin resistance:

It also makes insulin less effective, raising blood sugar levels, and contributing to type-2 diabetes. Sleep-deprived college students showed a 40% reduction in glucose clearance rates and a 30% decrease in insulin response. Fat cells from sleep-deprived people have poor glucose response.

7. Immunization impact:

Sleep deprivation reduces vaccination benefits. In a study, one night of sleep deprivation after Hepatitis vaccination resulted in 49% reduction in HPAV antibodies after 4 weeks.

8. Emotional health:

Sleep deprivation is linked to increased anxiety, depression, and volatile behavior. It is also associated with ADHD in children and marital discord due to a tendency to remember negative words more than positive ones. One in five high school boys in the US is diagnosed with ADHD. Studies show that sleep deprived people are twice as likely to remember negative words than positive words. This explains some of the marital discords.

9. Circadian rhythm:

Both sleep deficits and misalignment of circadian rhythm contribute to health problems. Sleep apnea increases the risk of cardiovascular disease by 420%, and sleeping less than six hours a night raises stroke risk by 4.5 times. A rare sleep disorder called Fatal Familial Insomnia leads to dementia and death.

10. Miscellaneous:

Heavy physical labor does not require extra sleep, while emotional stress may. Activities that increase core body temperature, like exercise or a hot bath, can facilitate sleep. Waking during the night is common and not necessarily indicative of disturbed sleep. Those who can “sleep anywhere anytime” are likely sleep deprived.

How much sleep?

A typical adult needs 7-9 hours of sleep and an adolescent needs 8-10 hours of sleep. Children need more. There are personal differences, but no adult needs less than 6 hours and any claims to the contrary are only reflection of their ignorance. Adverse effects to sleeping less are well understood but are there adverse health effects of sleeping too much? Over sleeping is not natural. Sleeping over 10 hours a night is abnormal. Studies have shown that subjects who were asked to sleep 14 hours at night could not sleep that much after the first few days. Once they have made up for a sleep deficit, it is not possible to sleep more and accumulate a surplus. Many people who claim to need less sleep, when brought under a controlled study, are surprised to find how their sleep duration expanded when the light and clocks are removed from their environment.

Sleep deficiency

Health consequences of sleep deficiency include following:

Higher Inflammation
Weight Gain & Obesity
Diabetes Risk
Cardio Vascular Disease
Cancer Risk
Reduced Immunity
Hormonal ImbalanceLack of Concentration
Hyperactivity
Emotional Instability
Depression & Burnout

Napping

1. Napping is very beneficial and it can help make up for sleep deficit at night. Hour for hour it is just as effective as sleep at night. However it does not help remove any circadian rhythm imbalances.

2. When it comes to memory processing, a 90 minute nap is as beneficial as a 6 hour sleep at night. However we don’t have data for immune function, endocrine function, hormonal function, clearance of toxins etc.

3. A good time to nap is early afternoon and not late afternoon.

4. If a person wakes up naturally at the time they need to wake up, they probably get enough sleep. Do they sleep longer on the weekends ? If so, they likely don’t get enough sleep during the week.

Sleep disorders

Here are some common sleep disorders.

1. Insomnia:

This refers to difficulty in falling asleep. There can be many causes like

Acute stress
Alcohol or caffeine
Circadian imbalance
Medical or neurological factors
Psychiatric disorders

2. Parasomnia:

This refers to unusual behavior at night.

Non REM Parasomnia like sleep walking or nightmares.
REM Sleep Behavior Disorders

3. Hypersomnia:

Excessive Daytime Sleeping

can be due to any of the following major causes:

Insufficient quantity of sleep at night
Poor quality of sleep
Sleep Apnea
Pathological disorders like Narcolepsy and Idiopathic Insomnia.
Medical or Psychiatric disorders like thyroid condition, cancer, medication side effects or mood disorders
Circadian Rhythm disorders like night shift job and jet lag.

4. Sleep apnea:

This is a sleep related breathing disorder. With this condition, people snore very loudly and stop breathing in the middle of their sleep.

5. Restless Leg Syndrome:

This is classified as a sleep related movement disorder and involves periodic limb movement.

Causes of sleep disorders

Melatonin deficiency
Caffeine and/or alcohol
Watching blue light emitting screens like TV, computer and cell phones before bedtime
Eating late dinners after it is dark outside
Snacking after dinner
Bright light and warm temperature
Erratic timing of sleep

As you can see there are many sleep disorders some are clearly due to diet and lifestyle but all may not be. If these persist even after making modifications in diet and lifestyle, one should consult a specialist.

Melatonin

Melatonin, a hormone produced in the pineal gland and enterochromaffin cells in the gut, is typically released after sunset. Traditionally known as a sleep hormone, recent research reveals its broader roles, especially in the body’s rejuvenation.

There are two types of melatonin: circulating melatonin, produced by the pineal gland and stimulated by darkness, and subcellular melatonin, found in mitochondria and protecting against oxidation and free radical damage. Subcellular melatonin is now considered primary, with pineal gland melatonin as a backup. Insufficient melatonin can disrupt sleep, increase inflammation, and reduce antioxidant protection, impacting conditions like hypertension, diabetes, and neurodegenerative disorders. Melatonin deficiency is linked to Sundown Syndrome in dementia and Alzheimer’s patients, characterized by agitation and fatigue at sunset.

Melatonin production is stimulated by darkness and infrared light but inhibited by brightness and blue light. Near-infrared (NIR) waves from the sun, comprising about 50% of solar energy, are major stimulants of subcellular melatonin. Historically, infrared exposure came from wooden fires, now replaced by fluorescent lights, which lack this benefit. Clouds and grass reflect infrared rays, making outdoor exposure beneficial even without direct sunlight.

Besides its antioxidant and anti-inflammatory benefits, melatonin offers numerous benefits:

1. Modulates the immune system and is effective against certain viruses.

2. Is neuroprotective, aiding memory and reducing anxiety and depression.

3. Controls the release of reproductive hormones in men and women.

4. Has cardioprotective qualities, lowering blood pressure and improving cholesterol profiles.

5. Plays a crucial role in insulin production and action, regulating GLUT4 expression, and reducing insulin resistance.

6. Lower melatonin levels are linked to higher incidences of breast and prostate cancers.

As melatonin production decreases with age, dietary sources become important. I do not advise taking melatonin supplements. Melatonin was discovered in plant foods in 1995, with rich sources including pistachios, cranberries, mushrooms, cherries, and walnuts. Consuming just two pistachios a day can suffice. A date-pistachio roll is a recommended dessert after dinner to boost melatonin intake.

To read the complete article on the Times of India, click here