Author: Hanni Yang
Editors: Junyu Zheng, Flynn Ma
Artist: Alvina Zheng
Have you ever stayed up at night, buzzing with energy and not wanting to sleep? Although a universal necessity, people approach and handle sleep differently. The rhythm of life is punctuated by the ebbs and flows of our sleep-wake cycles, which are determined by our internal body clocks called circadian rhythms. However, everyone carries their own rhythm regarding sleep patterns. Some people are night owls who thrive in the late hours of the evening, while others are early birds and greet the dawn with energy and enthusiasm. So, with such a stark contrast in habits between these two groups, what factors contribute to these chronotype differences?
At the heart of our sleep-wake preferences lie genetic predispositions. According to Doctor David A. Kalmbach’s research, the experiments indicate that certain genes influence our internal body clocks, shaping our circadian rhythms. Key genes such as Brain and Muscle ARNT-like proteins (BMAL1 and BMAL2), period (PER1, PER2, and PER3), Neuronal Pas Domain Protein (NPAS1 and NPAS2), and the Cryptochrome (CRY1 and CRY2) play crucial roles in maintaining and regulating these rhythms. Variations in these genes may lead to differences in when individuals feel most alert and energetic; for some, the evening is their playground, while for others, the morning holds endless possibilities.
Circadian rhythms, often called our internal biological clocks, orchestrate a symphony of physiological processes over a 24-hour cycle. These rhythms are controlled by complex biological mechanisms that regulate our sleep-wake patterns, hormone secretion, body temperature, and other important functions. Light, especially natural light, plays a key role in synchronizing our circadian rhythms, signaling to our bodies when it’s time to wake up and when it’s time to rest. Exposure to bright light, especially in the morning, helps calibrate our body clock and encourages us to stay awake, which is why those who soak up the morning sun may find themselves naturally inclined to rise with the dawn, while others exposed to sunlight later in the day may linger around dusk. However, our modern lifestyles, coupled with artificial lighting and irregular sleep schedules, can sometimes disrupt this delicate balance, leading to sleep disorders and health problems. The use of electronic devices emit blue light, which delays the release of melatonin, a hormone that promotes sleep. Exposure to this artificial light, especially before bed, can trick our brains into thinking it’s still daytime, making it harder for individuals to fall asleep. Additionally, shift work and irregular working hours can alter natural sleep patterns, leading to chronic sleep deprivation and increased risk of health problems such as cardiovascular disease, diabetes, etc. Night owls exhibit a delayed circadian rhythm, finding themselves most awake during later hours. In contrast, early birds have advanced circadian rhythms and feel most energetic during the morning sunlight. Understanding and respecting our circadian rhythms is essential for our optimal health and well-being.
Sleep patterns are not just determined by biological factors; they are also influenced by social and lifestyle factors that change over time. Our responsibilities, work schedules, and social activities shape our sleep habits for potentially our entire lives. These external factors, while influential, are not set in stone, as they can be adjusted and managed to improve our sleep quality. For example, a demanding job that requires late-night shifts can make someone a night owl, while a job that wakes up early can make them an early bird. Additionally, sleep preferences can change significantly with age. Teenagers are known for their tendency to stay up late, though as they enter adulthood, they often experience a shift to earlier bedtime and wake-up times. Likewise, older adults may wake earlier due to changes in circadian rhythms and sleep structure. Thus, the interplay between social demands, lifestyle choices, and the aging process leads to dynamic changes in our sleep patterns.
Our sleep patterns are much more complicated than we give them credit for. As we currently understand, they are determined by the multifaceted interplay of genetic predispositions, circadian rhythms, and social and lifestyle factors that evolve throughout our lives. While genetic influences lay the foundation for our natural tendency to be night owls or early birds, environmental factors such as exposure to light, social expectations, and personal commitments further shape our sleep-wake preferences. Moreover, as we move through different stages of life, our responsibilities, work schedules, and social activities have a large say in our sleep habits. Understanding these complex dynamics and recognizing the importance of respecting our circadian rhythms allows us to make informed choices that promote better sleep quality and overall health and well-being across the lifespan.
Citations:
Brown, Ritchie Edward. “Chronotype, circadian rhythm, and psychiatric disorders: Recent
evidence and potential mechanisms.” NCBI, 10 August 2022,
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9399511/. Accessed 30 April 2024.
“Genetic Basis of Chronotype in Humans: Insights From Three Landmark GWAS.” NCBI,
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6084759/. Accessed 30 April 2024.
Kamprad, Dennis. “How Does Your Circadian Rhythm Change As You Age (And Why?) –
Fit Sapiens.” Fit Sapiens, https://fitsapiens.org/circadian-rhythm-changes-with-age/.
Accessed 1 May 2024.