--- title: Does your menstrual cycle phase affect how alert and focused you stay during sleep deprivation? description: Yes, women in the follicular phase were less alert and performed worse on thinking tasks during sleep deprivation, especially at times when body temperature n url: https://niyora.com/research/papers/effects-of-menstrual-cycle-phase-and-oral-contraceptives-on-alertness-cognitive-1999/ --- - [Niyora](https://niyora.com/) - [Research](https://niyora.com/research/) - [Library](https://niyora.com/research/library/) - Does your menstrual cycle phase affect how alert and focused you stay during sleep deprivation? Non-randomised trial, 1999 # Does your menstrual cycle phase affect how alert and focused you stay during sleep deprivation? Yes, women in the follicular phase were less alert and performed worse on thinking tasks during sleep deprivation, especially at times when body temperature naturally dips. This is a small study without a comparison group. Early or limited evidence 25 healthy young women ## What they did 25 healthy young women stayed awake for 24 hours while researchers measured alertness, thinking ability, and body rhythms at different menstrual cycle phases using a controlled procedure. ## What they found Alertness and cognitive performance worsened during sleep deprivation and were poorest in the follicular phase, especially near the body temperature low point. Melatonin levels did not differ between cycle phases, but oral contraceptive use increased melatonin levels. Body temperature was higher in the luteal phase and in women taking oral contraceptives. ## What it means for you Hormonal changes from your cycle affect how tired you feel during sleep loss, but do not change when your body's natural 24-hour rhythm peaks and dips. The main limitation is the small sample size and lack of a comparison group. 25 women studied 24 hours sleep deprivation duration follicular phase when alertness was poorest ## About the study Original title Effects of menstrual cycle phase and oral contraceptives on alertness, cognitive performance, and circadian rhythms during sleep deprivation Authors Wright KP Jr, Badia P Journal Behavioural brain research Year 1999 Study design Non-randomised trial Participants 25 What was tested None - comparison of menstrual cycle phases Read the paper [doi.org/10.1016/s0166-4328(99)00042-x](https://doi.org/10.1016/s0166-4328(99)00042-x) ## Topics [Menstrual cycle and mood](https://niyora.com/research/topics/condition-cycle-mood/)[Sleep and insomnia](https://niyora.com/research/topics/symptom-sleep/)[Cognition, concentration and memory](https://niyora.com/research/topics/symptom-cognition/)[Oral contraceptives and drospirenone](https://niyora.com/research/topics/treatment-hormonal-contraceptives/)[Adolescents and young people](https://niyora.com/research/topics/life-area-adolescents/) Research tells you what helps on average. Niyora helps on the day it hits. Calm down, see it another way, and decide what to say, with a PMS and PMDD app built by a doctor. ## Related studies Survey study, 2025 Do menstrual problems and poor sleep affect mood and thinking in teenage girls? Survey study, 2025 What behavioral symptoms of premenstrual syndrome are most common? Survey study, 2017 Does painful menstruation affect adolescent girls' mood, emotions, sleep, and thinking? Non-randomised trial, 2014 Does the menstrual cycle phase change how one night of poor sleep affects the stress hormone cortisol? Survey study, 2022 How common is PMS in university students and what helps them cope with symptoms? Survey study, 2021 Does the menstrual cycle or birth control affect sleep and memory? Ask AI about this page Copy prompt ChatGPT ↗ Claude ↗ Perplexity ↗ Google AI Mode ↗ Grok ↗