What makes a person an early riser or a night owl?

Chronotype is influenced by differences in Circadian Rhythm, which refers to the fundamental 24-hour physiological cycle essential for various molecular and behavioral processes. It helps regulate sleep patterns.

The timing of circadian rhythms varies across individuals and is influenced by both environmental and genetic factors. People with earlier rhythms tend to rise early in the Morning and feel sleepy earlier in the night. If your body sides with the “morning clock” then you are a “morning person.” The other end of this spectrum has people with delayed rhythms. They tend to sleep and wake up late and are often referred to as an “evening person” or a “night owl.”

Research has shown that morning people are more focused, persistent, agreeable, plan their future better, and are less likely to smoke and drink or get depressed. They may exhibit characteristics like:
- Waking up early
- Being more active during the morning hours
- Being more focused and happy
- Being more productive during the day

Similarly, night owls enjoy a burst of strength during the night and may exhibit characteristics like:
- Waking up late
- Being more active during the evening hours
- Being more creative and adventurous
- Being more productive during the night

How Does Genetics Influence Circadian Rhythm?

A GWAS study of self-reported chronotype (morning/evening person) of UK Biobank data identified 22 regions in the circadian rhythm and photo-reception genes associated with morningness. This was also replicated in a 23andMe study.

One of the strongest associations was seen in the rs516134 SNP located near the RGS16 gene.

RGS16 Gene and Circadian Rhythm

The RGS16 gene encodes a protein that belongs to the regulator of G protein signaling. This protein is responsible for turning off certain signal communications between cells in the body.

Microarray studies and gene expression analysis have demonstrated that the RGS16 gene exhibits circadian variations. According to a study, mice lacking this gene have a longer circadian period.

rs516134 SNP and Morningness

The rs516134 is a C>T polymorphism located in the RGS16 gene. The C allele is found to be strongly associated with morningness.

Non-genetic Influences On Circadian Rhythm

A study found that morningness is significantly associated with gender, with a prevalence of 39.7% in males and 48.4% in females.

Also, people over 60 were more likely to prefer mornings than people under 30 - meaning people’s sleep preferences may change over time.

Effects of Circadian Rhythms

Circadian rhythms affect day-to-day bodily functions such as sleep, eating habits, hormones release, and body temperature.
Many studies have documented that irregular rhythms are linked to various chronic conditions such as sleep disorders, obesity, depression, diabetes, hypertension, bipolar, and schizophrenia.
It is known that the vast majority of patients with depression have sleep abnormalities; either they sleep too much or have insomnia and can’t sleep at all.
Several genetic variants are correlated with how circadian rhythms function and their association with health conditions.
The interplay between genetics and non-genetic factors (such as sunlight, eating habits) with circadian rhythm is clear.
Maintaining a routine with a balanced lifestyle may help to stabilize the internal biological clock and health.

Tips To Become An Early Riser

1. Sleep early and shift your bedtime gradually to get about 7-9 hours of sleep.
2. Stay consistent with your timings. Set your alarm clock to the same time every morning to make it easier to get into a routine.
3. 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.
4. Exposure to bright light in the morning, especially natural light, helps make you alert and gets you used to wake up early. Your body’s circadian rhythm is responsive to light and dark conditions.
5. 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.
6. Think about the various reasons why waking up in the morning could be beneficial and how you can be more productive during the day.
7. 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.
8. A protein-heavy meal is said to increase your dopamine levels, facilitating wakefulness, and making you ready for the day.

Summary

1. Circadian rhythm, which refers to the fundamental 24-hour physiological cycle essential for various molecular and behavioral processes, helps regulate your sleep patterns.
2. People with earlier rhythms are termed as morning people, whereas those with delayed rhythms are termed as night owls. Morning people are known to be more focused and happy, while night owls are known to be more creative and adventurous.
3. Both environmental and genetic factors influence your sleep patterns.
4. Several genes are known to affect circadian rhythm. The C allele of the rs516134 SNP in the RGS16 gene, which is involved in turning off certain signals between cells in the body, is known to be strongly associated with morningness.
5. Circadian rhythms affect your day-to-day functions, and irregularity is associated with chronic health conditions.
6. Following a routine with a balanced and healthy lifestyle can help set your biological clock right.

References:

https://pubmed.ncbi.nlm.nih.gov/27494321/
https://pubmed.ncbi.nlm.nih.gov/26835600/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5428740/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4018537/

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