Menstrual Cycle Sleep and the WHOOP Sleep Planner

We explain the physiological changes caused by the menstrual cycle, the effect hormonal birth control has on it, and how the WHOOP Sleep Planner now takes all of this into account.

The only part of the menstrual cycle that seems to get any attention is the menstruation part. Commonly referred to as "the period" or more shyly as "that time of the month," this is just one small piece of a beautifully intricate cycle of hormones that affects much more than our chances of getting pregnant. It also impacts how we sleep, recover, and respond to training.

Below, we walk through the physiology of the menstrual cycle, how hormonal birth control changes that physiology, and how WHOOP accounts for these physiological changes in the Sleep Planner.

How the menstrual cycle affects sleep

Although the menstrual cycle is mostly about reproduction, its effects span all your systems, including your circadian rhythm (biological clock best known for its role in regulating sleep and wake timing) and sleep architecture (fancy term for the distribution of sleep stages during a sleep). The premenstrual week — the end of the luteal phase right before menstruation begins — is known to be associated with relatively lower quality sleep and more time spent awake than during the rest of the cycle.

Because sleep efficiency varies by menstrual cycle phase, you can plan to allow for more time in bed during the late luteal phase to offset the reduced efficiency. For example, if you typically get 7.5 hours of sleep in an 8-hour sleep opportunity, you may want to give yourself an 8.25-hour opportunity to get that same 7.5 hours of sleep you need to feel your best.

The exact amount of reduced sleep efficiency varies from person to person depending on how sensitive you are to these hormonal changes. WHOOP measures your sleep and learns your individualized response to each menstrual cycle phase, incorporating this into a more personalized recommendation through the Sleep Planner.

Menstrual cycle phases and your circadian rhythm

At a high level, the menstrual cycle can be broken down into two phases. The first phase is called the follicular phase, which starts on the first day of menstruation (bleeding) and ends 11-27 days later with ovulation (releasing an egg). The luteal phase completes the cycle, running from ovulation to just before menstruation begins.

The follicular phase is defined by the release of hormones that tell your ovaries to produce sacs called follicles containing immature eggs. Although you get a few follicles each menstrual cycle, typically around 20, only one will mature into an egg released to the uterus. While this is happening, your uterus simultaneously prepares for the egg's arrival by thickening its lining and enriching it with life-sustaining nutrients.

Increases in progesterone and estrogen

The release of the egg into the uterus is called ovulation. This event marks the end of the follicular phase and the start of the 11-17 day luteal phase. Ovulation is also the time in the cycle when you can get pregnant.

In hopes of a fertilized egg implanting, the luteal phase brings with it increases in two key hormones, progesterone and estrogen. If the egg isn't fertilized within about a day of release, it will die. When the uterus gets the hint that it will not be hosting a fetus this month, the ovarian hormones drop.

This causes the changes to the uterine lining that were made to sustain the pregnancy to reverse, ultimately resulting in your period and the cycle beginning again.

The effect of hormonal birth control on sleep

Many people who menstruate choose to alter these hormonal cycles using hormonal birth control (HBC). People choose to use HBC to avoid pregnancy or to avoid unwanted symptoms the cycling hormones can have, such as painful cramps and acne breakouts. Not all birth control is hormonal — other options prevent pregnancy by creating a physical barrier between the sperm and egg, or by killing the egg or sperm.

HBCs come in many forms, from pills to vaginal rings, implants, injections, and IUDs. These birth control forms are all different delivery devices of the two primary hormones mentioned above, progesterone and estrogen. Either way, they work by preventing ovulation, meaning that even if sperm show up, there is nothing to fertilize.

Here's the thing though — if you are on HBC, even if you get a period the hormones in your birth control are dominating over your natural cycle. So while pre-HBC you might have had a cycle that looks like the graphic pictured above, you now have a cycle that looks like this:

The now evened-out hormones prevent the symptoms related to fluctuations, but also mean that what we're about to dig into in the remainder of this article will not apply to you because you don't have hormonally distinct follicular and luteal phases.

Ways to sleep better during your period

When your hormones fluctuate, your sleep behaviors need to adapt. Here are a few ways to improve your sleep quality during the most disruptive phases of your cycle:

1. Maintain sleep consistency. Going to bed and waking up at the same time every day helps regulate your circadian rhythm, which can offset some of the hormonal disruptions during your luteal phase.

2. Optimize your sleep environment. Your basal body temperature rises after ovulation. Keep your bedroom cool, dark, and quiet to help your body drop its core temperature, a necessary step for falling and staying asleep.

3. Adjust your sleep opportunity. Since sleep efficiency often drops right before your period, spend an extra 15 to 30 minutes in bed to ensure you get the actual hours of sleep your body needs to recover.

How to use Menstrual Cycle Insights in the WHOOP app

To take advantage of Menstrual Cycle Insights, you'll need to enable Hormonal Insights in the WHOOP app. This feature learns your individualized response to each menstrual cycle phase and incorporates this into a more personalized Sleep Planner recommendation.

1. Go to the Health Tab and select Menstrual Cycle Insights. 2. Tap the settings gear in the top right corner. 3. Toggle "Hormonal Insights" on.

Alternatively, you can tap "More" in the bottom navigation bar, go to App Settings > Hormonal Insights, and toggle the feature on.

Once you toggle Hormonal Insights on in your settings, the feature will be enabled. If you are new to tracking your cycle, there is a one-cycle calibration period (roughly one month) before your Sleep Planner recommendations will switch over to menstrual-cycle based coaching.

You can also log additional reproductive health metrics in the WHOOP Journal, including nursing an infant, hot flashes during sleep, menstrual cramps, bloating, and ovulating. By continuously tracking your cycle, WHOOP provides personalized insights that help you understand how your hormones affect your sleep, recovery, and overall performance.

Frequently asked questions about menstrual cycle sleep

What phase of your menstrual cycle are you most sleepy?

You are likely to feel the most sleepy during the luteal phase, specifically in the days leading up to your period. During this time, progesterone levels rise, which can have a sedative effect and increase daytime fatigue, while simultaneously disrupting your nighttime sleep architecture.

Can poor sleep affect your menstrual cycle?

Yes. Your circadian rhythm and reproductive hormones are closely linked. Chronic sleep deprivation or irregular sleep schedules can disrupt the release of luteinizing hormone and follicle-stimulating hormone, potentially leading to irregular cycles.

Are sleeping problems a common part of PMS?

Yes, sleep disturbances are a very common symptom of Premenstrual Syndrome (PMS). The sudden drop in estrogen and progesterone right before menstruation can cause insomnia, frequent awakenings, and a decrease in REM sleep.