"Staying Up Late Isn't Just Bad": Night Owls Outperform on Cognitive Tests, but Heart Disease Risk Also Increases

"Staying Up Late Isn't Just Bad": Night Owls Outperform on Cognitive Tests, but Heart Disease Risk Also Increases

"I'm a night owl..."


This phrase often gets dismissed as an excuse. People who can wake up early are seen as "highly motivated," while those who stay up late are considered "sloppy." This perception is somewhat inevitable, given that school and work schedules are typically designed around morning hours.


However, recent research challenges this simplistic dichotomy. In conclusion, being a morning person is not always the best, nor is being a night owl always a disadvantage. Instead, we are beginning to see the reality of a "mixed team" of morning people, night owls, and those in between, each with slightly different optimal times and risks.


What exactly are "morning people" and "night owls"?

The key is "chronotype," which, in simple terms, is the natural tendency of your body to feel sleepy or alert at certain times.UCLA Health describes chronotype as "the tendency of the body to prefer certain times for sleep and wakefulness," influenced by factors like age, genetics, light exposure, and lifestyle.


Interestingly, in addition to the broad categories of "morning type," "night type," and "intermediate type," there are classifications likened to animals (e.g., bear, wolf, lion, dolphin). This means that beyond just being "strong in the morning" or "strong at night," there are people whose sleep stability and focus peaks differ. This is where the "mixed team" aspect comes in.


Night owls have an advantage in cognitive tests

A topic that gained attention was a report based on research from Imperial College London. It highlighted differences in cognitive function scores (memory, reasoning, processing speed, etc.) based on chronotype, showing that night owls (those active in the evening to night) and intermediates tend to score higher than morning people.


The university's news release indicated that night owls scored higher than morning people in certain groups, and it also emphasized that "7-9 hours of sleep is optimal, and too little or too much can be detrimental." The point is that being a night owl is not about boasting about staying up late. Lack of sleep can ruin even a night owl's day, and oversleeping might also be harmful.


Additionally, a related study published in BMJ Public Health, which analyzed data from the UK Biobank, also suggested a link between chronotype, sleep duration, health, lifestyle factors, and cognitive function.


In essence, the cultural valuation of "morning people are superior" does not necessarily align with the biological tendency of when the brain functions best.


However—night owls might receive a "heart bill"

Ending here would make it seem like "night owls win!" but the reality is more complex. Another study reported at the end of January 2026 suggested that night owls (those active in the evening) have poorer cardiovascular health indicators and may be at higher risk for heart attacks and strokes.


American Heart Association's announcement and the abstract of a study published in the Journal of the American Heart Association indicated that night owls tend to score lower on overall cardiovascular health, with risk increases linked to "modifiable factors like lifestyle."


In short, here's the gist.

  • Night owls may have cognitive advantages if their environment suits them.

  • However, forcing themselves to fit into society's morning-oriented schedule can lead to sleep deprivation, poor diet, smoking, lack of exercise, and ultimately heart damage.


"Chronotype mismatch (social jet lag)" can be a pitfall for night owls.

The reality of the "mixed team": Intermediates are surprisingly common

While social media often turns into a battle between morning and night types, research and commentary highlight the significant presence of "intermediates." These are people who can perform "reasonably well" both in the morning and at night.


This adaptability is a strength in reality. They can easily adjust to societal schedules without the extreme misalignment that night owls might experience. So, the feeling of "I'm neither a morning nor a night person" is quite natural.


Social media reactions: Joy, critiques, and cries from the field

What makes this topic interesting is that it resonates with many people beyond the research itself. Social media reactions generally fell into four categories.


1) Joy from night owls (a rebuttal to long-standing labels)
In the night owl community, there was a strong sense of vindication. Posts like "It's finally time to hold our heads high and not be labeled as lazy!" were common.
Night owls seem to have a strong desire to be understood as having a "physiological trait" rather than a "lack of effort."


2) Realists' critiques (what time was the test taken?)
On the other hand, there were many calm critiques. A common one was, "What time was the cognitive test taken? Isn't it obvious that night owls would be disadvantaged if tested in the morning?"
Indeed, voices cautioning against overgeneralization, considering the limitations of the reports and research, were prominent.


3) Self-deprecation and humor (late-night vibes)
It's almost a tradition for night owls to self-deprecate during late-night hours, saying things like "I don't feel 'cognitively superior' at all right now." This humor reveals the struggle between their internal clocks and societal expectations.


4) Serious labor and school issues (can't we create night owl-friendly systems?)
Suggestions like "I feel best during night shifts or late shifts" or "Wouldn't a company made up entirely of night owls be strong?" were half-joking, half-serious.


However, there's a serious undertone. Continuously aligning night owls with fixed morning schedules can lead to chronic sleep debt, connecting back to the "heart bill."


So, how should we live?

Ultimately, turning this into a win-lose discussion misses the point. What's important is to "understand your chronotype, maintain sleep and lifestyle habits, and design your life to align with your peak times as much as possible."


Direction for practice (mindset)

  • Morning types: Convert morning concentration into "output." Don't cut it short by staying up late.

  • Night types: Ensure adequate sleep and schedule important tasks during the evening to night peak. Reduce morning commitments.

  • Intermediate types: Adaptability to societal schedules is a strength. However, avoid "aimless late nights" by fixing your bedtime.

  • For all types: Base your routine on 7-9 hours of sleep and prioritize modifiable factors like diet, exercise, smoking, and drinking to manage cardiovascular risks.


There are also implications for companies and schools. Instead of forcing everyone into a morning-oriented schedule, small changes like flexible hours, remote work, and considerate timing for tests and evaluations could enhance performance for some individuals.


Shifting the perspective from "night owls are lazy" to "night owls face design challenges" can ultimately reduce health-related costs.


Sources

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