News — WACO, Texas (May 17, 2023) – Many people perceive that they are night owls or morning larks, and that can’t be changed. It’s called a chronotype – your body’s need for sleep at a certain time – and it is generally considered to be unchangeable. However, a new study from researchers with Baylor University’s shows that chronotypes are more flexible than originally thought.
The research team’s findings, “,” were recently published in the journal Chronobiology International.
While genetics may predispose an individual to prefer the morning or evening hours, being a night owl can also result from behavioral choices. Whether driven by biology, institutional factors or behavioral choices, being an evening chronotype can be a detriment to sleep health, alertness in class and academic success.
Baylor sleep researcher , associate professor of psychology and neuroscience, and Blake Barley, doctoral candidate in psychology in Scullin’s sleep lab, examined how institutional factors, biological factors and behavioral choices play a role in sleep problems for college students and if chronotypes may more malleable than current theories suggest.
Through a series of questionaries given throughout the 2018-19 academic year, researchers asked 858 undergraduate students enrolled in demanding science courses to assess their sleep behaviors and quality, state their chronotype and rate their academic demands and stress levels, as well as the amount of their caffeine consumption and social media usage throughout the day.
FINDINGS
Evening- and morning-type students showed similar stress levels and academic demands, but evening chronotypes showed significantly worse sleep quality and duration. Evening types are disadvantaged when they have to wake up early for class or work.
The college students who identified as evening-types had several behaviors that are known to delay bedtimes, shorten sleep duration and worsen sleep quality. They used social media for 40 minutes while in bed, consumed caffeine later in the day and napped more than morning-types, which resulted in less night-time sleeping, worse sleep quality and greater sleepiness while in class.
As the semester progressed, some students reported a switch in chronotype. This chrono-switching was linked to changes in behavior, which resulted in improved sleep health, less sleepiness and higher semester GPAs.
ACTIONS
“Engaging in healthier daytime behaviors can lead to better sleep that then feeds back into better daytime life,” Scullin said. “When your daytime life is better, you can often get to bed and fall asleep earlier, enjoy better sleep quality and get into a good cycle.”
Students who switched from evening- to morning-types or who had stayed morning-types showed significantly better semester GPAs than students who stayed evening-types or switched from morning-to-evening types. They also reported consuming less caffeine after 5 p.m. and showed significantly better sleep quantity and quality.
Barley said some simple changes can improve sleep quality.
- Avoid electronics near bedtime.
- Avoid caffeine and other stimulants at least six hours before bedtime.
- Avoid long daytime naps.
- Avoid exercising in the evenings.
Scullin emphasized that chronotype malleability is a new idea, and that not all night owls should try to become morning larks or vice versa. The focus for each individual should be on getting the quality sleep they need to be healthy and productive.
This study was supported by the National Science Foundation [1920730 and 1943323].
ABOUT THE AUTHORS
’s research investigates how sleep physiology impacts memory, cognition and health. He also is interested in how we use memory to fulfill our daily intentions (a special kind of memory called “prospective" memory), including whether reminder apps and other technological solutions can reduce prospective memory difficulties in older age and the early states of Alzheimer's disease. He completed his doctorate in the Behavior, Brain and Cognition program at Washington University in St. Louis and then a post-doctoral fellowship in the Neurology and Sleep Medicine program at Emory University School of Medicine. He is involved in service committees for the Sleep Research Society, i serves as a columnist for Teaching Current Directions in Psychological Science at APS and co-founded the APA journal Translational Issues in Psychological Science.
Blake Barley is a graduate student at Baylor University working with Dr. Scullin in the . His research interests include examining the impact of sleep on cognitive processes like learning, memory and creativity. He also is interested in studying the impact of poor sleep behaviors on cognitive and academic outcomes. Barley said studying sleep and these various factors can lead to the development of better interventions to not only help people learn more about why sleep is important, but also lead to lasting improvements in their sleep health and behaviors.
In addition to Scullin and Barley, the research team includes Chenlu Gao, Tayler Luster, Abbye Porro, Mojgan Parizi-Robinson, Dena Quigley and Paul Zinke.
ABOUT BAYLOR UNIVERSITY
Baylor University is a private Christian University and a nationally ranked Research 1 institution. The University provides a vibrant campus community for more than 20,000 students by blending interdisciplinary research with an international reputation for educational excellence and a faculty commitment to teaching and scholarship. Chartered in 1845 by the Republic of Texas through the efforts of Baptist pioneers, Baylor is the oldest continually operating University in Texas. Located in Waco, Baylor welcomes students from all 50 states and more than 100 countries to study a broad range of degrees among its 12 nationally recognized academic divisions.
ABOUT THE COLLEGE OF ARTS & SCIENCES AT BAYLOR UNIVERSITY
The College of Arts & Sciences is Baylor University’s largest academic division, consisting of 25 academic departments in the sciences, humanities, fine arts and social sciences, as well as 11 academic centers and institutes. The more than 5,000 courses taught in the College span topics from art and theatre to religion, philosophy, sociology and the natural sciences. The College’s undergraduate Unified Core Curriculum, which routinely receives top grades in national assessments, emphasizes a liberal education characterized by critical thinking, communication, civic engagement and Christian commitment. Arts & Sciences faculty conduct research around the world, and research on the undergraduate and graduate level is prevalent throughout all disciplines. Visit the .
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