Many women don’t need to look at a calendar or open an app to know their period is approaching, thanks to telltale signs like bloating, breast tenderness, and moodiness. Although these are among the best-known symptoms of premenstrual syndrome (PMS), they are certainly not the only ones. Also on the list: sleep problems.
Research supports that. About 1 in 10 people suffer from insomnia – difficulty falling asleep or staying asleep. But twice as many people experience this when they are about to get their period. So says Sara Nowakowski, PhD, a sleep researcher at Baylor College of Medicine.
For some women, the problem at that point in their cycle isn’t insomnia. Instead, they don’t feel refreshed after sleeping, or they need more sleep than usual to feel well rested. And many say they feel more tired during the day.
Women with other PMS symptoms are more likely to have sleep problems. And if their PMS is severe, especially if it affects their mood, they are “more likely to experience insomnia and daytime sleepiness,” sleep physiologist Fiona Baker, PhD. She directs the Human Sleep Research Program at SRI International’s nonprofit Center for Health Sciences.
Women with premenstrual dysphoric disorder (PMDD), which is similar to PMS but causes more severe anxiety or depression for a week or two leading up to your period, have the best luck sleeping as they approach “that time of the month.” As many as 70% of women with PMDD experience insomnia before their period.
Why do sleep problems and PMS often overlap? “That’s the million-dollar question,” Nowakowski says. “It’s versatile.”
The simplest explanation is that common PMS symptoms such as bloating, breast tenderness, and pelvic or muscle pain can keep you awake. Feeling depressed, angry, anxious or irritable – also common PMS symptoms – can easily disrupt your restful sleep.
Mood and sleep are very closely linked. If you are stressed or depressed, you are more likely to have sleep problems. But a bad night’s sleep can also affect your mood the next day.
Additionally, many women look completely “normal” during sleep studies, Baker says, but still have trouble sleeping before their period.
It is real. “We never want to give the impression that it’s all in your head,” says Baker. “It’s more than what we measure [in the lab] doesn’t quite pick up on what someone is feeling.”
If you experience sleep fluctuations before your period, there is a good chance that changing hormone levels have something to do with it.
In women with normal menstrual cycles, estrogen and progesterone rise and fall at predictable times.
The average cycle lasts 25 to 36 days. Day 1 is the day your period starts. Exactly halfway through your cycle is the moment when you ovulate: an ovary releases an egg. About 5 to 7 days later, estrogen and progesterone levels peak before falling (if you haven’t become pregnant).
Progesterone remains higher for a little longer than estrogen. So as your period approaches – anywhere from 2 weeks to a few days before – you reach a point where progesterone is higher than estrogen. This hormone shift, which happens late in the cycle, can affect your sleep as you get closer to another period.
Experts believe that it is the change in levels, rather than low or high levels of estrogen or progesterone, that have the greatest potential to disrupt sleep.
“The worst time for sleep and mood, even in people without severe PMS, is the four to five days before your period through the first two days of your period,” says Nowakowski. For women who are more sensitive to hormonal shifts, the impact on sleep can be significant.
No one knows exactly how changing hormone levels late in your cycle affects sleep. But experts do know that there are estrogen and progesterone receptors in the brain – including in areas involved in controlling sleep.
“Progesterone in higher doses is linked to sleepiness,” says Baker, “which is one reason why women with PMS may feel sleepier during the day.”
During the latter part of your cycle, levels of the brain chemical serotonin also vary. One theory is that not having enough serotonin as your period approaches contributes to PMS symptoms like premenstrual depression and food cravings, as well as fatigue and sleep problems.
Your body temperature can also play a role. It rises slightly after ovulation and remains so until your period comes again (as long as you are not pregnant). Because body temperature naturally drops slightly before and during sleep, running when you’re slightly warmer than normal can make it harder to fall asleep or sleep well throughout the night.
Temperature can also affect your circadian rhythms (your body clock), Baker says. Some studies show that women with PMDD produce less melatonin, a hormone that helps tell your body it’s time to rest.
If you often have trouble sleeping before your period, there are things you can do to feel better overall.
Reduce salt, sugar, caffeine and alcohol. Resist the craving for chips or candy. Nowakowski recommends cutting back on salt and sugar (which are inflammatory) in an effort to reduce bloating. Instead, try eating more protein and complex carbohydrates. She also suggests cutting back on caffeine (a stimulant) and alcohol (a sedative).
Tackle your stress. Stress is a notorious sleep disruptor. Practicing stress management – for example by exercising, meditating or deep breathing – can help.
Talk to your doctor. If your PMS is severe – you may think you have PMDD – call your doctor. Depending on your symptoms, hormonal contraceptives or antidepressants can help both your mood and your sleep problems.
Consider therapy. If your biggest challenge is sleep—and practicing basic sleep hygiene measures like going to bed and waking up at the same time every day doesn’t help—you might also consider CBT-I, a form of cognitive behavioral therapy that focuses on changing thoughts and behaviors that cause your sleep problems.