A person sleeping in a bed with a pillow over their head. The person is holding a pair of reading glasses in their hand.The commonly used terms of “night owl” or “early bird” describe the cognitive and behavioral aspects of a person’s chronotype — their natural circadian system — in a 24-hour cycle. Night owls are known for their preference for “eveningness.” They feel more functional later in the day, sleep late, and wake late. Early birds are those who have a “morningness” preference. They feel more functional earlier in the day.

Your chronotype and sleep cycles can impact your health in a variety of ways. Impacts from sleep cycles may include:

  • Repercussions from “social jet lag”. A term used to define the difference in sleep and wake cycles between workdays and non-workdays.
  • The prevalence of sleep disorders such as delayed sleep-wake phase disorder (DSWPD).
  • Lowered cognitive performance and behavioral choices that stem from disrupted sleep patterns and cycles.

Understanding the impacts of chronotypes on health is important for healthcare providers. Those who are considering becoming an occupational therapist need to understand sleep as an occupational need in the various treatments and habits they encourage. This may include occupational therapy pediatric treatments such as establishing bedtime routines for children that can directly be impacted by the child’s chronotype.

What Is Chronotype?

A chronotype is a behavioral trait or preference for the sleep-rest cycle and daily activities to occur at certain times of the day. Research on chronotypes in the U.S. shows a general distribution of chronotypes in the studied population but noted distinct relationships between men and women, and age.

In general, adolescents peak in “lateness” or in their night-owl tendencies around the age of 18 to 19 with a drastic peak between the ages of 15 and 20. Thereafter, the early chronotype generally increases with age, with women reaching a plateau between 35 and 55, and men reaching a plateau from the age of 40 to 50.

The study noted how the night-owl tendency of adolescents coincides with a call for studies on the potential of later starting times for schooling in the morning, since teens may be at their highest cognitive function later in the day. The study also made note that with a general distribution and diversity of chronotypes in the population, the future opportunity to create flexible work arrangements that can be tailored to one’s own temporal niche and circadian rhythm could decrease long- and short-term health and safety risks.

Early Birds

Early birds are those who wake early and feel most refreshed, attentive, energetic, and active in the earlier part of a 24-hour cycle. The term “early bird” is typically used to reference individuals who are considered at the extreme end of the continuum for a preference of morningness.

Night Owls

Night owls typically note feeling refreshed, attentive, energetic, and active later in the day, tend to wake later in the day, and go to sleep later in the evening in a 24-hour cycle. The term “night owl” is typically used to reference individuals who are considered at the extreme end of the continuum for a preference of eveningness.


Not all people fit into extreme preferences, or the terms “early bird” or “night owl,” meaning they have more intermediate types of internal clocks. A study on chronotypes other than evening and morning types provided evidence of two intermediate types:

  • Napper — Those who are sleepier in the afternoon than in the morning and evening.
  • Afternoon — Those who are both sleepy in the morning and in the evening, noting their period of alertness in the afternoon.

The study also noted a section of the population who are neither morning, nor intermediate, nor evening types, and noted a commonality of all chronotypes within the participants of the study.

Is It Unhealthy to Be a Night Owl?

Though the results of various studies predominantly show a general dispersal of chronotypes across the population, the “early bird” chronotype is typically considered the societal standard. Society favors morning people over night owls, generally, attributing personal health, responsibility, productivity, and success to morning activities. This mindset is captured in the proverb made popular by Ben Franklin, “Early to bed, early to rise, makes a man healthy, wealthy and wise.”

Health Risks

A study on chronotype and health outcomes found that though there is no “chronotype gene” , though there are biological and environmental effects that contribute to your chronotype. Health hazards that were noted to occur more prevalently within “night owls” include:

  • Mood disorders;
  • Anxiety disorders;
  • Substance use disorders;
  • Personality disorders;
  • Insomnia;
  • Sleep apnea;
  • Arterial hypertension;
  • Bronchial asthma;
  • Type 2 diabetes;
  • Infertility;
  • Premature death.

In a comparison of “night owls” to “early birds,” night owls showed less resilience to adversity, less optimism for life, worse academic achievement, and difficulty adapting to irregularly scheduled work environments. “Night owls” were more likely to experience depressive symptoms or depressive states, increasing the likelihood of mental health and mood disorders.

Lifestyle Risks

The study of chronotypes and health outcomes found that “night owls” were more likely to have tendencies towards:

  • Alcohol consumption;
  • Tobacco consumption;
  • Substance abuse;
  • Irregular or unhealthy diet;
  • Less physical activity;
  • Lower quality, less, or irregular sleep.

Cultural Influence

The health and lifestyle risks that make life harder for night owls may be attributed to the forced acceptance of nine-to-five work schedules that are opposed to a night owl’s natural chronotype and circadian rhythm rather than the chronotype itself. Night owls also must cope with the health consequences of shift work and electrical lighting practices that disrupt circadian rhythm. Furthermore, night owls are prone to social jetlag from disrupted sleep cycles, which can directly influence higher risks for overall health.

Potential Solutions

A study on associations between chronotype, morbidity, and mortality did find relationships between higher rates of metabolic dysfunction and cardiovascular disease in night owls or those who have an evening preference. However, this increased mortality risk could be attributed to chronic misalignment between chronotype and cultural norms.

In other words, when a person’s chronotype and preference for eveningness doesn’t line up with the culturally imposed timing of work and social activities, it may cause health complications.

Solutions to health impacts for night owls may include attempts at interventions and circadian rhythm modification. Or, more flexibility when it comes to work and social activities would allow evening types to maintain their natural chronotype for better cognitive, mental, and emotional performance.

We may need to modify healthcare and occupational therapy’s role in sleep and the treatment of various disorders. It is important to note that continued study and research on the impacts of chronotype and sleep could shed further light on treatments and mechanisms that favor the eveningness chronotype. As researchers learn more, it is essential for healthcare providers and occupational therapists to stay up to date on their education so that they can treat and provide care to all types of chronotypes.

Image Source: https://unsplash.com/