How Knowing Your Chronotype Can Improve Your Sleep

During spring and summer, there are more hours of daylight to explore, get outside, and pursue your goals. To make the most of this time of year, you’ll need to know when your body is primed to perform and recover well. In this article, Vincent Mysliwiec, retired Army colonel and Professor of Research and Director of Sleep Medicine at UT Health San Antonio, shares how understanding your chronotype and circadian rhythm can help.

Cueing Circadian Rhythm

Circadian rhythm is often thought of as something that merely controls when you fall asleep and wake up, but it’s more complex than that.

“Circadian rhythm is a biological clock that entrains us to our environment,” Mysliwiec said. “It guides our normal sleep-wake cycle and impacts many other functions, such as when we perform best and digest food well.”

While circadian rhythm sets your biological clock’s pattern, its exact timing can be influenced by several different inputs.

“Zeitgebers are environmental cues that impact circadian rhythm,” Mysliwiec said. “The strongest is morning sunlight exposure, which entrains your biological clock and encourages your body to release naturally occurring melatonin to promote sleep. Exercise and meal timing, caffeine consumption, and other zeitgebers also have a lesser influence.”

Understanding Your Biological Clock

Circadian rhythm is closely related to your chronotype, which Mysliwiec defined as “an individual’s preference for being awake or asleep.” He said: “A ‘normal’ chronotype is someone whose regular bedtime is between 10 p.m. and midnight. The clock of morning larks will tell them it's time to go to bed earlier, while for night owls it will be later. Your circadian rhythm is inherent to your chronotype.”

As chronotype is largely genetic, it’s easy to ignore it. But if you know it, you can avoid work, family, and social schedules pushing you into sub-optimal sleep-wake patterns.

“Knowing your chronotype allows you to plan when you should go to bed and how to align your day to improve sleep,” Mysliwiec said. “When you sleep better, you’ll optimize its physical, cognitive, and restorative performance benefits. If your bedtime isn’t ideal for your chronotype, you can simply move it earlier or later.”

Sometimes your chronotype can be self-evident. But if you’re not sure, Mysliwiec advises taking the Morningness-Eveningness Questionnaire (MEQ). You could also use extended time off to self-assess.

“Note when you feel sleepy and then when you want to go to bed,” Mysliwiec said. “A wearable like the Oura ring can also help triangulate your ideal bedtime.”

Solving Sleep Issues for Shift Workers and Service Members 

Inadequate sleep has short-term effects like reducing cognitive output and impacting certain elements of physical performance. Long-term sleep deprivation is associated with higher incidence of all-cause mortality, cardiovascular disease, and diabetes. Shift workers are one of the populations most affected by a schedule that’s misaligned with their chronotype. A 2015 study found that synchronizing work and circadian time improved their sleep quality and wellbeing.

“If you’re on rotating shifts, there’s little you can do,” Mysliwiec said. “But if you’re always on a night or morning shift and your chronotype doesn’t align with that, the most important thing is to set a regular sleep schedule, even on your days off.”

Military personnel are another demographic that struggles with circadian misalignment. While most service members have to get up early and assessing chronotypes isn’t widespread, initiatives like POTFF (Preservation of the Force and Family) and H2F (Holistic Health and Fitness) prioritize sleep.

“In my military career, any time you knew someone had a delayed chronotype, it was ideal to put them on the night shift, as it was easier for them to stay awake and perform well,” Mysliwiec said. “Rather than framing it as a problem, I’d tell the commander that they have an asset who can do things that others don’t want to.”

Adjusting to Race Times and Stabilizing Sleep-Wake Patterns

A 2018 study suggested that misaligning sleep times with circadian preference decreases athletes’ sleep quality, so a late or early event time that doesn’t fit your chronotype could decrease performance. While Mysliwiec doesn’t believe you can switch chronotypes, you might be able to make a beneficial adjustment before a race.

“If you know in advance when you’d like to go to bed to still get the extra sleep that athletes need, you can slowly shift your sleep schedule,” Mysliwiec said. “If you’re a night owl who usually goes to bed at 1 a.m., you could pull that back in 15-minute increments until you’re at 11:30 p.m. to get better rest for a 7 a.m. wake-up. But your biological drive will probably override the adjustment afterward.”

For anyone who struggles to sleep because of chronotype misalignment, Mysliwiec suggests:

• Get sunlight exposure within two hours of waking and keep sleep and wake times consistent.

• Challenge yourself physically and mentally daily so you’re tired enough to sleep.

• Avoid caffeine within six hours of bedtime, stay under 400 mg daily, and drink no more than two alcoholic drinks so you don’t disrupt restorative sleep.

• Put away screens and other bright lights 90 minutes before bed and remove devices from your bedroom. Manage noise with earplugs and keep the thermostat low.

• Allow your brain to transition from the busyness of the day by reading, journaling, or making a to-do list an hour before bedtime.

• Take a warm bath 90 minutes before bed. A 2019 study found this promotes better sleep. After the temporary heat up, core temperature drops to signal melatonin production.

• Supplement with research-backed ingredients such as Magnesium L-threonate, L-Theanine, and Apigenin to promote rest and calm the nervous system.

To support your body’s sleep-wake cycle, try Sleep by Momentous today.