---
title: Does how sleepy women feel change at different times of day during the menstrual cycle?
description: Yes. During daytime hours, women feel more sleepy and have more deep sleep during naps in the second half of the cycle, but sleepiness does not differ at othe
url: https://niyora.com/research/papers/diurnal-fluctuation-of-sleep-propensity-across-the-menstrual-cycle-1999/
---

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- Does how sleepy women feel change at different times of day during the menstrual cycle?

Study, 1999

# Does how sleepy women feel change at different times of day during the menstrual cycle?

Yes. During daytime hours, women feel more sleepy and have more deep sleep during naps in the second half of the cycle, but sleepiness does not differ at other times of day.

 Moderate study design

Healthy women (sample size not specified)

## What they did

Healthy women participated in an ultra-short sleep-wake schedule study measuring their 24-hour sleep patterns during the first half (follicular) and second half (luteal) of their menstrual cycle.

## What they found

During daytime hours (09:00 to 16:30), subjective sleepiness and the number of deep sleep-containing nap trials increased in the luteal phase compared to the follicular phase. The mean overall sleep propensity did not change. During evening and night hours (17:00-00:30 and 01:00-08:30), there were no differences between the two phases.

## What it means for you

Increased daytime sleepiness in the luteal phase may be related to how the brain controls deep sleep. The study was small and only included healthy women, with no separate control group mentioned.

## About the study

Original title Diurnal fluctuation of sleep propensity across the menstrual cycle Authors Shibui K, Uchiyama M, Okawa M et al. Journal Psychiatry and clinical neurosciences Year 1999 Study design Study Open access Yes Read the paper [doi.org/10.1046/j.1440-1819.1999.00489.x](https://doi.org/10.1046/j.1440-1819.1999.00489.x)

## Topics

[Sleep and insomnia](https://niyora.com/research/topics/symptom-sleep/)

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