BEST AND WORST TIME OF DAY

Yay for 5 p.m., boo for a.m.

It appears that the night is really darkest just before dawn: Scientists have discovered that 5 a.m. is officially the worst time of day, based on mood, circadian clock, and other factors.

Researchers from the University of Michigan and Dartmouth Health discovered that this is when people reported their lowest mood regardless of when they got up. By contrast, 5 p.m. is when the majority of people are at their cheeriest, according to the study.

“Mood naturally cycles with lowest point in the morning and highest in the evening independent of sleep deprivation,” explained Benjamin Shapiro, psychiatrist at Dartmouth Health and lead author of the study, which was published in the PLOS Digital Health Journal.

Fitbit analysis

Shapiro and his team arrived at this conclusion by analyzing the Fitbit data from 2,602 medical interns over the course of two years. They used his wearable health-tracking device’s results to gauge the participants’ continuous heart rate, step count, sleep data and daily mood scores.

Meanwhile, measuring the interns’ heart rates and motion allowed scientists to estimate their circadian time as well as their time awake.

“We discovered that mood follows a rhythm connected to the body’s internal clock, and the clock’s influence increases as someone stays awake longer,” said senior author Danny Forger, who teaches mathematics at the University of Michigan med school.

In conjunction with the Fitbit analysis, researchers would also periodically ask students to rate their mood on a scale from 1 to 10.

Researchers discovered participants’ moods would worsen the longer they were awake.

“Sleep deprivation is a separate process that further decreases mood,” explained Shapiro. “So someone awake all night at 5 a.m. should have an even lower mood than if they just woke up at 5 a.m.”

He added, “However, on a typical day their mood at 5 a.m. will still be lower than that in the evening.”

Of course, this study is not without its caveats. The team analyzed a small sample in an artificial laboratory setting. This may not accurately reflect the complexity and nuance of mood variation and how it’s affected by factors such as social dynamics, schedules and temperaments, per the study.