Overview

Why Do Living Organisms Sleep?

Sleep is a universal behavior observed across many species. While its exact functions are still being explored, it serves multiple vital roles. It offers a period for physiological restoration and rejuvenation, aids memory consolidation and learning, helps emotional regulation, and boosts immune function. Despite variations in sleep patterns and durations among different species, the commonality of sleep suggests it offers a range of evolutionary advantages critical for survival and well-being.

Is Insomnia Genetic

What Is Insomnia?

Insomnia is a prevalent sleep issue that can make it difficult to fall asleep, stay asleep, or cause you to wake up earlier than desired without returning to sleep. Despite spending time in bed, you may wake up feeling fatigued. Insomnia can affect your energy, mood, overall health, job performance, and quality of life. The amount of sleep an individual requires can differ, but adults generally need between seven and eight hours per night.

Many adults will eventually encounter short-term or acute insomnia, typically triggered by stress or a significant life event. This usually lasts for a few days to weeks. Others may experience chronic insomnia, which persists for a month or longer and could be a standalone issue or linked to other medical problems or medications.

Fortunately, enduring sleepless nights is not inevitable. Making simple adjustments to your daily routine can bring about improvements.

Is Insomnia Genetic?

A 2020 meta-analysis of twin studies estimated the overall heritability of insomnia to be approximately 40%. According to a 2012 review of sleep disorders, 35% of people with insomnia have a positive family history, with the mother being the most commonly affected family member. Some of the most well-studied genes and polymorphisms related to insomnia are described below:

5-HTTLPR

The serotonin transporter gene region, commonly known as 5-HTTLPR, is frequently studied in psychiatric genetics, including its relationship with insomnia. 

5-HTTLPR is a genetic variant in the serotonin transporter gene, SLC6A4, also known as SERT. This gene is responsible for the reuptake of serotonin, a neurotransmitter that plays a significant role in mood regulation, among other functions. The 5-HTTLPR variant affects how efficiently serotonin is recycled back into nerve cells after release. This can influence an individual’s susceptibility to mood disorders like depression and anxiety. 

Numerous studies have investigated the 5-HTTLPR polymorphism short and long-allele variants. Some research has also looked at sleep issues within the broader context of mental health disorders, finding noteworthy results. 

A 2010 association study discovered that the short allele of the 5-HTTLPR was significantly more common in individuals with insomnia compared to the control group (47.1% vs. 39.9%)

Another cross-sectional study published a few years later found that each short (S) allele of 5-HTTLPR increased the risk of insomnia by over 80% and highlighted a significant interaction with job-related stress. In people with two short alleles (SS genotype), those experiencing high job-related stress had an elevated risk of insomnia, while those with low pressure had a reduced risk. 

A 2014 review also emphasized the role of 5-HTTLPR in affecting sleep quality through stress reactivity mechanisms.

Adenosine Receptors

Adenosine, a substance that promotes sleep, starts at low levels in the morning and accumulates as the day progresses. Elevated adenosine levels and proper activation of its receptors are crucial for good sleep quality at night. Genetic variations that impair the function of adenosine receptors may be associated with insomnia associated with caffeine intake.

Among the four adenosine receptors (A1R, A2aR, A2bR, and A3R), A1R regulates the sleep-wake cycle, while A2aR plays a role in initiating sleep. The genetic variant rs5751876 within the A2aR is found to be associated with insomnia in connection to caffeine consumption. 

A 2019 study showed that individuals with the rs5751876 T allele in the ADORA2A gene, which codes for the A2aR receptor, have a decreased risk of insomnia and general sleep complaints.

Other Genetic Markers

A 2016 study provided preliminary evidence for the potential role of the DRD4 VNTR polymorphism in daytime drowsiness. Another study identified a significant association between DAT1 rs464049 polymorphism and sleep duration in adults. Both DRD4 and DAT1 genes influence the dopaminergic system, a set of pathways that have been widely studied in relation to cognition, reward mechanisms, and motivation. Given the involvement of the dopaminergic system in sleep regulation, it has been cited as a potential target for future research. Recent research has also extended to other genes in the dopaminergic system, such as catecholamine-O-methyltransferase (COMT). 

Other studies indicate the influence of the PGC-1α polymorphisms in an increased risk of insomnia. A 2012 study investigated how variations in PGC-1α might be related to insomnia among people with the Apoε4 risk allele – one of the most well-researched genetic links for Alzheimer’s disease. The study on 202 patients and 253 controls found that the GG allele of PGC-1α increased the risk of insomnia after controlling for sex, age, major depressive disorder, and Apoε4.

A 2014 study on middle-aged women examined polymorphisms in both AHR repressor (AHRR) and CLOCK genes, individually and in combination. Polymorphisms in both genes, AHRR (rs2292596) and CLOCK (rs1801260) were linked to reduced risk of insomnia, suggesting that they serve as protective factors. Women with homozygous or at least one AHRR G allele and CLOCK C allele had a reduced risk of insomnia compared to those homozygous for AHRR C and CLOCK T alleles.

Learn more about LifeDNA’s Sleep Report

What Are the Symptoms of Insomnia?

Symptoms of insomnia can include:

  • Struggling to fall asleep at night
  • Waking up intermittently throughout the night
  • Rising earlier than intended
  • Feeling unrefreshed after a sleep
  • Feeling tired or drowsy during the daytime
  • Experiencing irritability, depression, or anxiety
  • Having trouble concentrating, completing tasks, or remembering things
  • Increased frequency of mistakes or accidents
  • Persistent concerns about your sleep quality

When to Consult a Physician?

If insomnia negatively affects your ability to function during the day, it’s advisable to consult a healthcare provider for a diagnosis and treatment plan. Should your physician suspect you have a sleep disorder, you may be referred to a specialized sleep center for additional tests.

Why Is Sleep Important?

Sleep is crucial for various aspects of human health and well-being, serving both physiological and psychological functions. Here are some reasons why sleep is important:

Physical Health:

  • Restoration and Repair: During sleep, your body works to restore and repair your immune system, muscles, and heart. Tissues grow and repair themselves during sleep.
  • Hormonal Regulation: Sleep is essential for regulating hormones that control growth, stress, and even your appetite. For instance, inadequate sleep can lead to insulin, cortisol, and leptin imbalances, increasing the risk of obesity and diabetes.
  • Brain Health: Sleep helps in the process of neurogenesis, the formation of new neurons. Lack of sleep can interfere with neurological functions and lead to problems like memory loss and impaired cognitive abilities.

Psychological Well-being:

  • Mental Health: Adequate sleep can improve mood and help manage stress and anxiety. Sleep deprivation is strongly linked to various mental health issues, including depression and anxiety disorders.
  • Cognitive Functions: Sleep enhances cognitive functions like memory, problem-solving skills, and attention. During the deep stages of sleep, your brain consolidates memories and skills, making learning and remembering more effective.
  • Emotional Stability: Sleep has a significant impact on emotional regulation. A lack of sleep can make you more irritable and significantly affect your judgement.

Safety:

  • Reduced Risk of Accidents: Sleep deprivation increases the risk of accidents. Lack of focus and slower reaction times are common consequences of poor sleep, leading to traffic and workplace accidents.
  • Enhanced Performance: Athletes and anyone who engages in physical activity can benefit from adequate sleep. Sleep improves physical performance, increases energy levels, and aids in quicker recovery after exercise.

Quality of Life:

  • Social Interactions: Being well-rested generally makes you more alert, more engaging, and better equipped to interact socially, which is crucial for overall well-being.
  • Productivity: Good sleep can make you more productive by enhancing your creativity, concentration, and problem-solving skills.

Given these multi-faceted benefits, it’s clear that sleep isn’t a luxury but a necessity for a healthy, fulfilling life.

Lack of sleep can have serious repercussions. 

  • Sleep deprivation generally leads to decreased attention, working memory, cognitive speed, short-term memory, and reasoning skills. 
  • A survey showed that one-third of commercial truck driving accidents resulted from drowsiness due to insufficient sleep. 
  • According to the National Transportation Safety Board, driving after being awake for more than 20 hours is akin to driving while intoxicated, tripling your risk of a car accident. 
  • Furthermore, inadequate sleep has been correlated with heightened risks of cardiovascular diseases, including heart disease, high blood pressure, arrhythmias, diabetes, and obesity, even after accounting for demographic and socioeconomic factors.

Stages of Sleep

The human body alternates between two main types of sleep: 

  1. REM, or rapid eye movement sleep, and 
  2. NREM or non-rapid eye movement sleep. NREM sleep is split into three sub-stages, known as N1, N2, and N3. 

Differences in muscle activity, brain wave activity, and eye movement distinguish these phases and stages. Generally, the body goes through four to six full cycles of these stages each night, with each cycle lasting around 90 minutes on average.

  • Wake Stage: When awake and alert, your brain primarily emits high-frequency, low-amplitude beta waves. As you relax, these give way to alpha waves.
  • Light Sleep (N1): Making up 5% of sleep time, this stage is marked by theta waves. It serves as a short transition between wakefulness and deeper sleep.
  • Deeper Sleep (N2): Characterized by sleep spindles and K-complexes on EEG, this stage makes up about 45% of total sleep. It’s crucial for memory consolidation. The N2 stage is also typically when any teeth grinding (bruxism) occurs.
  • Deepest Sleep (N3): This slow-wave stage is characterized by delta waves, with the lowest frequency but highest in amplitude. It is when tissue repair, immune strengthening, and sleep-related phenomena like sleepwalking may happen.
  • REM Sleep: Although brain activity here mimics wakefulness, REM sleep is a distinct stage linked to dreaming and cognitive processing. It accounts for roughly 25% of total sleep and becomes longer as the night progresses.

Each stage is crucial in mental and physical restoration, contributing to overall well-being.

Tips To Improve Your Sleep

Avoid Blue Light at Night

One simple yet effective step to enhance your sleep quality and set your body clock right is to reduce blue light exposure at night. Gadgets like phones, TVs, and LED bulbs emit blue light, affecting your natural sleep cycle and reducing melatonin production. You can wear blue-light-blocking glasses to minimize its effects. These glasses are designed to block 100% of blue light.

Change Your Home Lighting

You can switch to color-changing or yellow-hued bulbs for nighttime use. Known as candlelight or Edison bulbs, these emit less blue light. Dimming your home’s overall lighting in the evening can help, too. Turn off bright overhead lights and use lamps fitted with these softer bulbs. It’s also a good idea to shut off your electronic devices a couple of hours before bedtime.

Make Your Bedroom Dark

Your bedroom should be as dark as possible for optimal sleep. Even a tiny amount of light from street lamps can interfere with melatonin production. Consider installing blackout curtains or shades and covering up small lights on electronic devices to create a dark sleep environment.

Keep it Cool

Your body naturally expects cooler temperatures when it’s time to sleep. Maintain a cool but comfortable bedroom temperature for better sleep. Consider specialized water-cooled mattress toppers to help keep your bed cool.

About the LifeDNA Sleep Report

Sleep is essential for everyone’s health and well-being. LifeDNA’s Sleep Report gives an insight into several traits that can help you optimize your sleep at night.

LifeDNA’s Sleep report covers an analysis of Insomnia and (9) other sleep-related traits. Get yours here.

LifeDNA’s Sleep report also covers an analysis of your natural Melatonin levels. Get yours here.

Get your LifeDNA Skincare report before your doctor visit

Summary

  • Sleep is vital in physiological restoration, memory, emotional regulation, and immune function.
  • Sleep is crucial for physical health, psychological well-being, safety, and overall quality of life.
  • Lack of sleep leads to cognitive impairments and increases the risk of accidents and health issues like cardiovascular diseases.
  • The human body cycles through different stages of sleep —REM and NREM— which contribute to mental and physical restoration.
  • Insomnia is a common sleep disorder that can disrupt sleep quality, affect daily function, and reduce quality of life.
  • Insomnia symptoms include trouble falling asleep, waking up frequently, and feeling fatigued during the day.
  • Consult a healthcare provider if insomnia negatively impacts your daily functioning.
  • Some evidence suggests that insomnia has a genetic component, with several genes and neurotransmitter systems potentially implicated.
  • Tips for better sleep include avoiding blue light at night, optimizing bedroom lighting and temperature, and considering melatonin supplements.

*Understanding your genetics can offer valuable insights into your well-being, but it is not deterministic. Your traits can be influenced by the complex interplay involving nature, lifestyle, family history, and others.

Our reports and suggestions do not diagnose or treat any health conditions or provide any medical advice. Consult with a healthcare professional before making any major lifestyle changes or if you have any other concerns about your results.

References

  1. https://pubmed.ncbi.nlm.nih.gov/35659072/
  2. https://pubmed.ncbi.nlm.nih.gov/33222383/
  3. https://pubmed.ncbi.nlm.nih.gov/31237183/
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2831428
  5. https://pubmed.ncbi.nlm.nih.gov/25154585/
  6. https://pubmed.ncbi.nlm.nih.gov/24480386/
  7. https://www.sleepfoundation.org/how-sleep-works/adenosine-and-sleep
  8. https://pubmed.ncbi.nlm.nih.gov/22754043/
  9. https://pubmed.ncbi.nlm.nih.gov/17407504/
  10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6335867/
  11. https://pubmed.ncbi.nlm.nih.gov/25466290/
  12. https://pubmed.ncbi.nlm.nih.gov/22392034/
  13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3750063/
  14. https://pubmed.ncbi.nlm.nih.gov/20438143/
  15. https://pubmed.ncbi.nlm.nih.gov/17205864/
  16. https://www.nsc.org/road-safety/safety-topics/fatigued-driving
  17. https://www.sciencedirect.com/science/article/abs/pii/S0149763416302184
  18. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5703049/

*Understanding your genetics can offer valuable insights into your well-being, but it is not deterministic. Your traits can be influenced by the complex interplay involving nature, lifestyle, family history, and others.

Our reports have not been evaluated by the Food and Drug Administration. The contents on our website and our reports are for informational purposes only, and are not intended to diagnose any medical condition, replace the advice of a healthcare professional, or provide any medical advice, diagnosis, or treatment. Consult with a healthcare professional before making any major lifestyle changes or if you have any other concerns about your results. The testimonials featured may have used more than one LifeDNA or LifeDNA vendors’ product or reports.