Going to bed late is not always a scheduling problem. Sometimes people intend to sleep, have no good reason to stay up, and still keep delaying bedtime. This study asks how that pattern can be measured in Japan. Getting sufficient sleep at the appropriate time is important for maintaining physical and mental health and performance.

Sleep loss interferes with thinking and emotion regulation, resulting in difficulties in social adjustment. Therefore, getting sufficient sleep at the appropriate time is essential not only for individuals’ health but also for socioeconomic benefits.

That makes repeated bedtime delay more than a private annoyance. To measure the tendency toward bedtime procrastination, the Bedtime Procrastination Scale was developed and validated. This self-reported measurement consists of nine items measuring subjective bedtime procrastination.

The scale has been translated and validated in several languages, but a Japanese version had not yet been developed. Bedtime procrastination has been regarded as a factor causing sleep problems. The Japanese version was developed through four steps: translation, translation back into the original language, interviews using the questionnaire, and expert checking.

The idea is like translating a recipe, then having someone translate it back: differences become visible before people rely on the result. The same checking was used here to make the questionnaire fit Japanese readers. The results from the exploratory factor analysis supported a two-factor model, indicating that this structure was appropriate for the questionnaire data.

In plain terms, the two named dimensions were preparing for bedtime and adhering to bedtime, respectively, giving the measure its two distinct parts. The two-factor version fit better than a one-factor version, but Item 2 had a low factor loading, so Item 2 was eliminated and the model was confirmed again.

BPS-J score was significantly related to shorter sleep duration on workdays, more frequent days of feeling daytime fatigue, and more frequent days of feeling sleep loss. It was also related to viewing bedtime procrastination as a problem less seriously.

The pattern connected the bedtime-delay score with both lost sleep and how seriously people regarded the delay. The BPS-J is believed to enhance the assessment of underlying factors that contribute to insufficient sleep syndrome among daytime workers in Japan.

This facilitates interventions specifically targeting bedtime procrastination. This approach may be more effective than often ineffective traditional advice of simply telling individuals to go to bed earlier. It allows specific behavioral interventions aimed at curbing bedtime procrastination by replacing behaviors.

The study has limits: participants were limited to daytime workers, and the diagnosis relied solely on participants’ self-reported accounts. The Japanese scale should therefore be applied to other populations, such as students, with caution.

Individuals whose bedtime procrastination was so severe that they could not perform daytime work were not included. Additional studies including such individuals are necessary for further clarification. The Japanese bedtime-delay scale was reliable and connected with shorter workday sleep, more daytime fatigue, and more sleep loss.

It could help replace vague advice with more targeted support.