Women’s Health, Circadian Rhythms and Sleep

Women’s health, sleep, and circadian rhythms are closely connected throughout life. Reproductive hormones can influence both sleep and the body’s internal 24-hour timing system, but hormones are only part of the picture. Health conditions and symptoms can also affect sleep. Daily schedules, work, and caregiving can shift when sleep is possible.

Sleep and circadian patterns can begin to change after puberty and may shift across the menstrual cycle. Pregnancy and menopause bring further changes. Women are more likely than men to experience insomnia, while some sleep disorders become more common or present differently at certain stages of life.

Looking across the full 24-hour day can reveal patterns in sleep timing and regularity that might otherwise go unnoticed. Changes in daytime activity or symptoms can provide additional clues for how to help you optimize your wellbeing.

Sleep and circadian rhythms are regulated by several interacting systems in the brain and body. Reproductive hormones are part of that picture. Estrogen and progesterone can affect brain regions involved in sleep and wakefulness. They can also influence body temperature, breathing during sleep, and aspects of the body’s internal 24-hour timing system.

Because estrogen and progesterone change across the menstrual cycle and during major reproductive transitions, their effects on sleep and circadian timing can change too. The pattern is highly individual.

Biology is only one influence. Menstrual symptoms and pain can interfere with sleep. Mood or other health conditions may also play a role. Medications can affect sleep or alertness. This combination of biological and everyday influences means that the same life stage can affect two women very differently.

Puberty and the menstrual cycle

After puberty, reproductive hormone cycling adds another source of variation in sleep and circadian physiology. Across the menstrual cycle, changes in estrogen and progesterone can affect sleep stages and body temperature. Body temperature is typically higher after ovulation, with a smaller nighttime decline. However, controlled studies have not found consistent evidence that the timing of the body clock itself shifts across the menstrual cycle.

Some women notice changes in sleep around the days before menstruation or during the first days of bleeding. Menstrual symptoms can contribute. Pain, headaches, mood changes, PMS (premenstrual syndrome), or PMDD (premenstrual dysphoric disorder) may all make sleep more difficult. Irregular or heavy periods have also been associated with poorer sleep in some studies.

However, there is no single menstrual-cycle sleep pattern. In women without significant menstrual symptoms, objective measures such as sleep duration and sleep continuity often change relatively little across the cycle. This helps explain why one woman may notice a clear monthly pattern while another does not.

How long a woman sleeps is only one part of sleep and circadian health. When sleep occurs and how consistent that timing is from day to day may also be relevant.

Light and darkness are the strongest signals that synchronize the circadian system. Sleep-wake timing and daily routines can also reinforce the pattern. Research suggests that women may, on average, have somewhat earlier or more stable rest-activity rhythms than men, although research on sex-specific circadian differences is still limited.

Research suggests that sleep health is not only about how many hours a woman sleeps. When she sleeps and how consistent that timing is may also play a role. In a study of nearly 1,200 women with an average age of 65, researchers used wrist monitors to measure sleep over about a week. Women with more irregular sleep timing reported lower psychological well-being and more symptoms of depression and anxiety. These associations remained even after researchers accounted for sleep duration and time awake during the night. 

The study also found differences in sleep timing and regularity among racial and ethnic groups. This suggests that healthy sleep timing is unlikely to be defined by one universal clock time. Individual biology, daily schedules, and social or environmental factors can all influence when sleep normally occurs.

Some sleep problems are more common in women. Others can become more prominent or present differently at certain life stages.

Insomnia

Insomnia involves persistent difficulty falling asleep or staying asleep. It can also involve waking earlier than intended and being unable to return to sleep. For insomnia to become a disorder, the sleep problem also affects how someone functions during the day.

Women experience insomnia more often than men. Hormonal changes may contribute at certain life stages, but persistent insomnia should not automatically be attributed to hormones. Other factors may be involved, or a separate insomnia disorder may be present.

Obstructive sleep apnea

Obstructive sleep apnea (OSA) causes repeated narrowing or closing of the airway during sleep. This can interrupt sleep and reduce oxygen levels.

OSA is more common in men before menopause, but the difference between men and women becomes much smaller after menopause. Women with OSA may also be less likely to fit the stereotypical picture of obvious snoring and pronounced daytime sleepiness. They may instead report insomnia or fatigue. Poor sleep quality and frequent nighttime urination can also occur. Some commonly used OSA screening questionnaires are also less sensitive in women. Together, these factors can contribute to OSA being overlooked.

Restless legs syndrome

Restless legs syndrome (RLS) causes an uncomfortable urge to move the legs that is usually worse during rest and in the evening or at night. It occurs more often in women than men and can become particularly common during pregnancy.

A persistent sleep problem can therefore be a sleep disorder in its own right rather than simply a consequence of hormones, stress or a particular stage of life.

Looking across the full 24 hours can help reveal patterns that may be affecting sleep and circadian health. Sleep is not separate from the rest of the day. A difficult night may lead to more napping or less activity the next day, while symptoms, medications, work, or caregiving can shift the timing of sleep and wakefulness.Sleep problems do not have to be accepted as an unavoidable part of menstruation, pregnancy, menopause, or aging. There are often times during the day that can be adjusted to better support sleep and daily rhythms. Understanding your own pattern can help identify where changes may be useful and when a sleep problem warrants further attention. Useful questions include:

• Does sleep change at a particular point in the menstrual cycle? 
• Have bedtime and wake time become less regular? 
• Has daytime napping or sleepiness increased? 
• Do symptoms tend to become worse at a particular time? 
• Has daylight exposure or physical activity changed? 
• Have work, caregiving, or medication schedules shifted? 

The goal is not to create a perfect schedule. It is to create a daily pattern that works for you and supports healthy sleep and circadian rhythms. Tracking what changes across the day and night can help you see where adjustments may be possible and give you clearer information to discuss with a healthcare professional. 

A short record can make sleep concerns easier to discuss. Useful things to track include:

• Bedtime and wake time
• Night wakings
• Naps and daytime sleepiness
• Menstrual-cycle timing, if relevant
• Pain, mood changes or other symptoms
• Snoring, gasping or witnessed pauses in breathing
• Restless or uncomfortable legs at night
• Medication timing
• Major changes in work, caregiving, daylight exposure or activity

Tracking cannot diagnose a sleep or hormonal condition, but it can help a healthcare professional see how symptoms fit together across the full day and night. Bringing this information to an appointment can help focus the discussion on what may be contributing and whether further assessment is needed. Women do not have to wait until poor sleep becomes severe before raising it as a health concern.