27 Apr Chill your pillow for better premenstrual sleep
- Research shows that sleeping on a cold pillow in the second half of your cycle (luteal phase) leads to longer, deeper sleep.
UPDATED April 27, 2022 (originally published May 23, 2019)—Tend to toss and turn in bed during the week or two before your period? Are you tired even after a full night’s sleep and wish you could wake up more refreshed and energized?
The trick to a sounder night’s sleep on these cycle days could be as simple as sleeping on a cold pillow, research shows.
What happens to sleep in your luteal phase?
How quickly you doze off and how soundly you sleep can vary according to where you are in your menstrual cycle. For example, in the first half of your cycle (the follicular phase that spans from the first day of your period through ovulation), you may find it’s easier to fall asleep and stay asleep thanks to rising estrogen, which increases sleep-promoting serotonin in the brain.
However, during the second half of your cycle (the luteal phase that spans the day after ovulation through the day before your next period), you could find it more challenging to drift off, stay asleep or reach the deepest stages of sleep that enable you to wake up feeling fully rested.
One reason for these sleep challenges is due to plunging estrogen. This hormone dips twice during the second half of your cycle: during the three days after ovulation, then again during the six days before your period. As this hormone drops, the level of brain chemicals that help manage sleep, such as serotonin and melatonin, also decrease. On top of that, descending estrogen can make you more sensitive to common sleep disrupters, such as noise, light and aches.
But, turns out, descending estrogen isn’t the only hormone behind lousy sleep in your luteal phase. According to researchers from Okayama University and Kansai University of Social Welfare in Japan, progesterone is also to blame.1
The progesterone/sleep connection
During the second half of your cycle, your level of progesterone is higher than it is in the first half. One side effect of a higher amount of this hormone is that your body temperature rises about one-half to one degree. While that doesn’t sound like much of a change, it’s enough to disrupt your slumber.
That’s because one key way your body triggers the onset of sleep is by dropping your core body temperature. This means if your core body temperature is higher–even slighly–it could interrupt this process, delaying sleep or making it less restful.
The easy fix
Fortunately, this research team discovered that there’s an easy solution to this high-progesterone problem: Chill your head as you sleep on these cycle days. Resting your head against something cold cools the blood in your scalp, which then travels around your body, bringing down your temperature. This counteracts progesterone’s heat-spiking effects, helping you nod off faster and get deeper, more restful zzzs.
To prove this, the study authors recruited 14 women who had regular menstrual cycles as well as excessive daytime sleepiness during their luteal phase. They then asked them to sleep on a pillow topped with a sheet that contained tubes circulating cool water during two different times in their luteal phase. Their temperatures were measured as they slept and the researchers monitored their sleep quality by using an EEG device to measure brain waves. The study participants also answered a questionnaire about how well they felt they slept.
The results: The women experienced less “arousal” during their sleep and more slow wave sleep, indicating they clocked deeper, more restful zzzs. Participants also reported feeling less drowsiness during the daytime, possibly because of their sounder sleep.
How can you get this sleep-boosting effect?
You can simulate the chilled pillow used in the study by popping a gel cold pack in the refrigerator for about 10 minutes before heading to bed, then laying it on top of your usual pillow.
Other options: You can put your regular pillow in the freezer for about 10 minutes before settling in to bed. Or, turn on a gentle fan directed at your head to keep it cool.
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(1) Seiji Hamanishi, et al., “Head cooling during sleep improves sleep quality in the luteal phase in female university students: A randomized crossover-controlled pilot study,” PLOS ONE, published online March 25, 2019