Sleep increased and bedtimes were later during the early months of the coronavirus pandemic, according to a study published in Sleep Health, which analyzed Fitbit data during the spring of 2020.

The study zeroed in on Fitbit user data across six major U.S. cities to gain insights about the impact of the pandemic on participants' bedtime and sleep duration during the early days of the pandemic.

"Overall, compared to 2019, mean sleep duration in 2020 was higher among nearly all groups, mean sleep phase shifted later for nearly all groups, and mean sleep duration and bedtime variability decreased for nearly all groups (owing to decreased weekday-weekend differences).

"Over the course of January to April 2020, mean sleep duration increased, mean bedtime shifted later, and mean sleep duration variability decreased," the authors of the study wrote.

Researchers said that by May and June of 2020, these changes began shifting back to historical norms.

TOP LINE DATA

The average sleep duration increased during the beginning of the coronavirus pandemic in March and April of 2020. In the first few months of 2020 user sleep data was similar to previous years. However, in March and April the number of hours began to increase.

The data found that women between the ages of 18 to 29 had the greatest changes in sleep. In fact, 32% of those users spent 30 minutes or more in bed in April than January. Across genders, younger participants saw more increases in time in bed.

"Younger adults may live under increased circadian pressure to advance their sleep period to conform to social norms and work schedules. When the opportunity was presented, this age group went to bed later but slept more," article author Michael A. Grandner, Ph.D. MTR, director of the sleep and health research program at the University of Arizona, said in a statement.

However, the bedtimes also became later. In fact, 42% of men and 41% of women between the ages of 18 and 24 delayed sleep by more than 30 minutes from January to April. Older adults saw less of a change, with 26% of women and 23% of men over the age of 65 pushing bedtime back by 30 minutes or more.

HOW IT WAS DONE

Fitbit data was collected from 163,524 active users who had enabled heart rate and sleep-detection functions. All participants lived in either Chicago, Houston, Los Angles, San Francisco, New York or Miami. Data was collected from January, February, March and April of 2020.

According to researchers, users were randomly selected as long as they fit the criteria of being an active users. Researchers compared the 2020 data to the past two years by collecting separate aggregated samples of Fitbit users from each month in 2018 and 2019.

THE BACKGROUND

Fitbit has been used in a number of studies around health and wellness. In fact, npj Digital Medicine published a paper outlining how Fitbit could help predict the onset of COVID-19 and the likelihood of hospitalization.

The wearable, which is now owned by Google, has also been used in research for heart rate variability and flu tracking.