The most important sleep metric isn’t hours slept

A recent study has highlighted that sleeping consistently is more crucial than sleeping longer for both restfulness and overall health. Researchers conducted a study on college students, who are often used as test subjects due to their easily accessible living conditions and willingness to participate in research for perks like gift cards.

The study found that irregular sleepers, who had more variability in their sleep duration, onset time, wake time, or quality, performed worse academically and had a higher risk of mortality compared to regular sleepers. Regular sleepers slept less but went to bed earlier, took fewer naps, and spent more time asleep at night. This led to a finding that irregular sleepers had a 30% lower risk of mortality, making sleep regularity a stronger predictor of health than duration.

The study, published in 2023, has sparked a surge in research on sleep regularity, resulting in over 300 studies in the past six years. The findings suggest that sleep regularity is more impactful on health than how long a person sleeps, and it is linked to a range of health issues such as depression, obesity, hypertension, dementia, cardiovascular disease, and death.

Experts like Dr. Marie-Pierre St-Onge, the founding director of the Center of Excellence for Sleep and Circadian Research at Columbia University, attribute the neglect of sleep regularity to the difficulty of collecting daily sleep data in population-based studies. However, the rise of inexpensive wearable devices that monitor sleep has made it easier to evaluate sleep behaviors in recent years.