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[Article] Why Do Abnormal Sleepiness Occur Before Menstruation?

Supervisor: Dr. Ayako Shibata

Do you find it challenging to maintain focus or experience daytime sleepiness even with the usual amount of sleep just before your menstrual cycle? Sleepiness can persist from premenstrual to menstrual periods, affecting some to the extent of disrupting work. The strong sleepiness felt before menstruation is one of the symptoms of Premenstrual Syndrome (PMS).

Abnormal sleepiness serves as an alarm for the body. Let's explore ways to incorporate refreshment and short naps into our routine to better cope with the body's needs.

Explanation of the Mechanism Behind Abnormal Sleepiness

Feeling sleepy before menstruation is attributed to the influence of body temperature, the autonomic nervous system, GABA, and serotonin, leading to a decline in sleep quality.

Cause 1: Increased Body Temperature Before Menstruation

Female body temperature is susceptible to hormonal influences, and it varies throughout the menstrual cycle (menstruation, follicular phase, ovulation, luteal phase). During the luteal phase, which occurs after ovulation and before menstruation, the secretion of the hormone "progesterone" increases. As a result, the body temperature rises by about 0.3°C to 0.6°C above the normal range.

There is a deep connection between body temperature and sleep. The luteal phase, characterized by increased progesterone, elevates basal body temperature, reducing sleep quality and making daytime sleepiness more likely.

Cause 2: Reduced GABA Leads to Increased Tension and Stress Sensitivity

GABA is an amino acid present in the human brain. It is known to alleviate tension and stress, induce relaxation, and promote sleep.

However, GABA is sensitive to progesterone, and about a week before menstruation, when progesterone levels rise, GABA decreases. On the other hand, the interaction of progesterone with GABA receptors enhances sedation and sleep induction, leading to daytime sleepiness.

Cause 3: Decreased Serotonin Levels

Serotonin, often referred to as the "happiness hormone," is a neurotransmitter in the brain. When the brain senses stress, it releases serotonin to regulate the balance of the autonomic nervous system. Additionally, serotonin serves as a precursor to "melatonin," a substance essential for quality sleep.

However, during the luteal phase, serotonin secretion decreases. Consequently, it becomes challenging to relax and achieve deep sleep, resulting in daytime sleepiness.

About Premenstrual Hypersomnia

If you experience abnormal sleepiness before menstruation, it might be a type of PMS called "Premenstrual Hypersomnia" or "Menstrual-Related Hypersomnia." Difficulty sleeping before menstruation is termed "Premenstrual Insomnia," while abnormal daytime sleepiness is referred to as "Premenstrual Hypersomnia."

In typical cases of Premenstrual Hypersomnia, strong daytime sleepiness occurs approximately a week before menstruation and subsides once menstruation begins. Individuals with pronounced symptoms of other PMS, such as mood swings, irritability, and lower abdominal pain, tend to experience significant daytime sleepiness.

A diagnosis of Premenstrual Hypersomnia is made when intense sleepiness persists for more than two days and continues for over a year.

Improving Difficult Premenstrual Symptoms with Low-Dose Pills

The treatment for Premenstrual Hypersomnia starts with adjusting lifestyle. Keep a sleep record using apps or a diary, and use it to manage your well-being and schedule. During the premenstrual period, ensure exposure to sunlight during the day and avoid excessive caffeine intake at night. Moderate exercises like walking, yoga, and stretching can contribute to better sleep. If the physical and mental symptoms before menstruation significantly impact daily life, treatment options may include low-dose birth control pills or hormonal medications to suppress ovulation. This treatment aims to eliminate hormonal fluctuations and improve symptoms. Other approaches, such as traditional Chinese medicine or antipsychotic drugs, might also be considered.

It's important to note that the use of low-dose pills or hormonal medications has certain conditions and may not be suitable for those wishing to conceive. If you're experiencing abnormal sleepiness before menstruation, consider consulting your primary healthcare provider for personalized advice.


Supervisor's Profile

Dr. Ayako Shibata (柴田綾子)

Specialist in Obstetrics and Gynecology, Perinatal Medicine, and Fetal Medicine Yodogawa Christian Hospital

After graduating from Gunma University School of Medicine in 2011, Dr. Shibata completed her initial training in Okinawa and has been in her current position since 2013. Engaging in activities centered around disseminating information on women's health and conducting seminars, she concurrently provides prenatal check-ups and outpatient gynecological care.

Published works: "Emergency Room for Women: Currently Diagnosing!" (Chugai Iji Shuppan, 2017), "Pocket Guide for Obstetrics and Gynecology" (Koho-do, 2020), "Essence of Women's Healthcare 100" (Japan Medical News, 2021).


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