Being A Night Owl May Be Worse For Your Health Than You Think

Approximately half of Americans snooze between the hours of 11 p.m. and 7 a.m., reports Vox. These hours place us smack dab in the center of what scientists refer to as the chronotype bell curve. Referring to our preferred hours of sleep, people can fall into as many as six different chronotypes (via Science Alert). More often than not, though, science focuses on two of the more well known chronotypes: early birds and night owls.

Previous research has shown that staying up late has the potential to negatively impact our health. A 2018 longitudinal study published in Chronobiology International found that adults in the U.K. who stayed up later had a 10% increased risk of all-cause mortality compared to early risers. Lending further evidence to the ways in which staying up late may affect our health, researchers from a new 2022 study published in Experimental Physiology have found metabolic differences between those with later and earlier sleep preferences. The study team used survey data to split 51 sedentary adult participants into one of two groups: those with an early chronotype (EC) or a late chronotype (LC). Their findings showed that night owls may be more susceptible to type 2 diabetes and cardiovascular disease compared to those with an earlier chronotype (via WebMD).

The EC and LC categories were used to assess differences in energy-burning sources when participants were at rest, as well as when they were physically active, as per the study. The research team also tracked indicators of daytime sleepiness in participants, such as drifting off to sleep while watching TV or in a stopped car.

Findings showed that early risers tend to be more physically active during waking hours and burn more fat while exercising and resting, reports WebMD. Alternatively, carbohydrates seem to be the main energy-burning source for those with a later chronotype. This difference in fuel sources indicates that individuals who stay up late may be more susceptible to heart disease or diabetes due to an increased chance of fat accumulation (via The Guardian). The researchers also found that the early risers were more sensitive to insulin levels, but night owls did not display this same degree of sensitivity.

"A potential explanation is [those with a late chronotype] become misaligned with their circadian rhythm for various reasons, but most notably among adults would be work," Steven Malin, senior author of the study, told The Guardian.