The time of day when you are least productive will surprise you

Everyone has a time of day when they feel the most productive (much of it determined by our feeding schedule) but new research may have you reconsidering yours.

In a new study conducted by researchers at the IZA Institute of Labor Economics, a team from Monash University in Australia, and the University of Granada in Spain aspired to determine the most productive time of day.

Dawn is commonly associated with sustained output among the general public, but the research literature is actually much more nuancedoften factoring things like age, chronotype, and career path into the analysis.

In order to establish an approximate time window that corresponds with increased productivity for the average healthy young adult, the authors of the new paper analyzed the performance of University students taking exams in the final two weeks of their semester. Exams were scheduled, quasi-randomly at these three different times-of-the day: 9:00 am, 1:30 pm, and 4:30 pm.

The results indicate that productivity and performance peak a little after midday. It should be noted that the most profound effects pertained to tasks involving fluid intelligence (e.g. problem solving, logic thinking, and abstract reasoning).

This means the findings supported by the new study are not limited to academicians, given most of us require fluid intelligence skills on a near-daily basis. The findings were consistent among men and women, and low- and high-performing students.

“We find that peak performance occurs around lunchtime (1:30 pm), as compared to morning (9:00 am) or late afternoon (4:30 pm). This inverse-U shape relationship between time-of-day and performance is not driven by stress or fatigue, is consistent with the idea that cognitive functioning is an important determinant of productivity and (iii) implies that efficiency gains of up to 0.14 standard deviations can be achieved through simple re-arrangements of the time of exams,” the authors wrote in the paper.

“While researchers have shown that biological factors influence changes in productivity between day and night shifts, we establish that such relationship is also important within a standard day-light shift.”

Interestingly enough, the strength of these time-of-day effects appeared to be diversified between the Fall and Spring exam sessions.

Students who took exams during lunchtime in January, at the end of the first semester, evidenced an increase in performance of 0.094 SD, while students taking an exam during lunchtime between May and June, at the end of the second semester, increased their performance by only 0.043 SD.

Although the authors go on to speculate about the correlating mechanisms behind the data indexed above, further research will be needed to draw any concrete conclusions.

“On one hand, time-of-day may affect the behavior of individuals around the time of the exam, such as their study strategy, food intake, or sleep patterns. On the other hand, since time-of-day affects cognitive functioning, this could, in turn, affect their performances at the moment of the task. Our dataset does not contain information that allows us to identify, separately, the magnitude of each mechanism driving the results,” the authors add.

Ultimately, our specific circadian rhythms will determine how faithfully our output reacts to the afternoon productivity windows posited by the new data.

Circadian rhythms refer to the physical, mental, and behavioral changes that follow a 24-hour cycle and dictate how living things respond to light and darkness.

Chronotypes are the biologically driven, behavioral manifestations of our circadian clocks. Familiarity with our specific chronotypes allows us to maximize our performance and the effects of different sleep and dietary functions based on our hormones. There are four common chronotypes studied among humans.

Below are brief descriptions of each as well as the duration each is historically the most productive and the bedtimes that energize their productivity.

The Lion (medium sleep drive): Fifteen to 20% of the population fall beneath the Lion. Lions are driven and focused early risers that rarely nap and are most alert at noon.

Up at 6:00 am – 470 min = 10:10 pm. bedtime

The Dolphin (low sleep drive): Ten percent of the population belong to the dolphin chronotype. The majority of dolphins are insomniacs, as they more often than not wake up feeling unrested.

Up at 6:30 am – 400 min = 11:50 pm bedtime

The Bear (high sleep drive): Members of the Bear chronotype account for 50% of the population. They are typically extroverts that optimally perform around mid-morning to early afternoon.

Up 7:00 am – 470 min = 11:10 pm

The Wolf (medium sleep drive): Wolves account for the remaining 15-20% of the population. They’re impulsive, creative, moody night owls, that don’t require a lot of sleep to function. 

Up at 7:00 am – 400 min = 12:00 am

Chronobiology additionally suggests that many people operate differently depending on the seasons. The new paper supports this as well, with some students demonstrating marginal improvements during certain months compared to others.

Still, the afternoon was associated with increased performance to some degree or another, all year round, for the vast majority of participants involved in the analysis.

“The main implication is that tasks involving fluid intelligence are more affected by time-of-day and should be moved to the early afternoon, particularly at times of the year when sunlight exposure is limited. Depending on the type of job, an optimal sorting of the tasks may lead to incredibly relevant efficiency gains,” the authors continued.

“Indeed, in the final discussion of the paper, we apply our insights to one important context that is likely to benefit from our research, namely the sorting of elective surgeries, which we use as a case study. We show to what extent a simple change in schedules can lead to a marked decrease in mortality rate.”