Introduction
Sleep is a critical component of optimal health. A healthy sleep comprises various aspects, including adequate duration, good quality, and the absence of sleep disorders. Inadequate sleep at night is generally associated with:
- Daytime sleepiness
- Daytime fatigue
- Depressed mood
- Poor functioning
- Other health issues
Sleep duration refers to the total amount of sleep obtained either during the nighttime sleep event or across the 24-hr period.
Importance of An Adequate Sleep
Getting enough sleep at night is very important for several reasons. Sleep is linked to your mental and physical health and quality of life. When you get adequate sleep at night, you can be more productive and concentrate better during the day. It reduces your risk of heart disease and prevents depression. Your immune system becomes stronger as sleep helps the body to repair and recover. Your athletic performance can also be improved because of a good night’s sleep. Not getting enough sleep can make you gain weight faster.
RDA: What Is The “Ideal” Sleep Duration?
National Sleep Foundation guidelines recommend 7-9 hours of sleep per night for healthy adults. Babies, young children, and teens need even more sleep to enable their growth and development. People over 65 should also get 7 to 8 hours of sleep per night.
How Does Genetics Affect Sleep Duration?
Studies have shown that certain genetic variants influence habitual sleep duration, which explains why some individuals need more sleep than others.
Twin studies have shown that the heritability estimation of sleep duration is around 10 - 40%.
A GWAS study of self-reported chronotype and sleep duration of UK Biobank data identified several genetic regions associated with sleep duration. This study documented that people with genetic variants for longer sleep duration reported an average of 22 minutes more sleep.
PAX8 Gene and Sleep Duration
The PAX8 gene encodes a member of the paired box (PAX) family of transcription factors involved in thyroid follicular cell development and the expression of thyroid-specific genes.
Variations in the PAX8 gene may affect different functions, including DNA binding, gene activation, and protein stability.
Research studies have found that the sleep-wake cycle may be influenced by regulating thyroid hormone levels. Individuals with hypothyroidism (a condition in which the thyroid gland does not produce enough thyroid hormones) are prone to excessive sleepiness. People with hyperthyroidism (in which the thyroid makes too much of the hormone), on the other hand, may have insomnia.
rs62158211 And Sleep Duration
The rs62158211 is a G>T polymorphism located in the PAX8 gene. The T allele is associated with longer sleep duration.
A study documented that the rs62158211 was associated with an average 2.6-minute per-allele change in sleep duration.
Non-genetic Influences On Sleep Duration
Some risk factors that lead to shorter sleep duration include alcohol consumption, smoking, and physical inactivity.
Effects of Sleep Duration on Health
Few epidemiological and genetic studies have demonstrated a strong biological link between abnormal sleep duration, risk of schizophrenia, type 2 diabetes, fetal growth, and Crohn's disease.
Sleep duration is also associated with cardiovascular diseases, type 2 diabetes, depression, automobile and workplace accidents, learning and memory problems, and prospective mortality.
TipsTo Become An Early Riser
- Sleep early and shift your bedtime gradually to get about 7-9 hours of sleep.
- Stay consistent with your timings. Set your alarm clock to the same time every morning to make it easier to get into a routine.
- Move your alarm clock to a distance where you would have to get up to turn it off. There are a few apps like Smart Alarm or Math Alarm which require you to do an activity to turn off the alarm. This will help you stay awake and not snooze your alarm and go back to sleep.
- Exposure to bright light in the morning, especially natural light, helps make you alert and gets you used to waking up early. Your body’s circadian rhythm is responsive to light and dark conditions.
- Get active in the morning and go for a jog or run. You can even hit the gym in the morning and finish your workout. This will give you the energy to start your day.
- Think about the various reasons why waking up in the morning could be beneficial and how you can be more productive during the day.
- Use something to look forward to in the morning as bait to wake up for. A cup of hot coffee, a nice breakfast, a puzzle in the newspaper are a few of the things that you could look forward to.
- A protein-heavy meal is said to increase your dopamine levels, facilitating wakefulness, and making you ready for the day.
Summary
- Sleep duration refers to the total amount of sleep obtained during the nighttime sleep event or across the 24-hr period. Getting enough sleep at night is necessary for both mental and physical well-being.
- For healthy adults, 7-9 hours of sleep is recommended. Babies, children, and teens tend to sleep for much longer.
- Genetics is found to influence sleep duration. The PAX8 gene, which plays a role in thyroid development, is associated with the sleep cycle. The regulation of thyroid hormone levels affects the sleep-wake cycle. The T allele of the rs62158211 SNP in this gene is associated with longer sleep duration.
- Certain risk factors like smoking, alcohol consumption, and physical inactivity lead to decreased sleep duration.
- Abnormal sleep duration is linked with the risk of schizophrenia, type 2 diabetes, fetal growth, and Crohn's disease.
- Exercising during the day, following a proper sleep routine, reducing alcohol consumption and smoking, a comfortable environment, and less frequent napping are some of the things that can make your sleep duration normal.
References:
https://www.sleepfoundation.org/articles/how-much-sleep-do-we-really-need
https://pubmed.ncbi.nlm.nih.gov/27992416/
https://pubmed.ncbi.nlm.nih.gov/27494321/
https://pubmed.ncbi.nlm.nih.gov/25469926/
