Credit: Getty
Strong Women
Keep having vivid nightmares? Your hormones could be to blame – here’s why
By Katie Scott
10 months ago
6 min read
Scientists are delving into how hormone fluctuations can impact not only our sleep quality but also our dreams…
There’s a shadow moving towards me from the top of the stairs. I’m stood absolutely still, barely able to breathe but desperately needing to gasp from the speed of my racing heart. I’m willing myself to move – to raise my arms to protect myself but… I can’t. Then, in a flash, it’s all over. I’m there, lying in my bed with my eyes open, my heartbeat banging in my ears and my body soaked with adrenaline-fuelled sweat. Once again, I’ve woken from a horridly vivid nightmare – and it happens several times a month.
Studies have proven that women have more nightmares or intense dreams than men, with experts suggesting that gender differences in processing stress and anxiety – including pressure from societal expectations – might be a potential cause. According to the University of the West of England, women are more likely than men to share their dreams in general, so there is a chance that men dream as frequently as we do but just aren’t talking about them as much.
But there may also be a more biological reason for our incessant vivid dreams: our hormones.
How do hormones impact our sleep?
The two main reproductive hormones, oestrogen and progesterone, have the greatest impact on our sleep, explains Kate Organ, a hormones and mental health clinician. “Oestrogen is involved in our sleep architecture (the structure of our sleep) throughout the night – controlling the different sleep phases, namely non-REM and REM,” she tells Strong Women. Progesterone, meanwhile, directly acts on “inhibitory pathways within the brain, causing sedation and relaxation effects. This helps to induce and maintain sleep.”
Progesterone
Progesterone also plays a role in how we experience nightmares and vivid dreams, says Dr Katherine Sharkey, associate professor of medicine at Brown University. Her research has looked into the roles that changing progesterone levels during our sleep cycle can cause our sleep to become more erratic: we might wake more during the night, for example, or cycle through sleep stages quicker. Known as sleep fragmentation, this causes us to experience – or better remember – dreams.
“People who have more fragmented sleep are more likely to remember their dreams,” Dr Sharkey tells Strong Women. That’s because when our sleep is disturbed, we’re more likely to wake up soon after a REM cycle (which is when most dreaming tends to happen).
“During a typical night of sleep, most people have two to four bouts of REM sleep, which is associated with the experience of dreaming,” Dr Sharkey says. If someone thinks they never dream, she continues, it’s because they enjoy deep, unfragmented sleep. “If we don’t wake up close to the time of a dream, the dream content doesn’t get transferred to our long-term memory.”
In other words, we all dream (dreaming is a way of consolidating information and working through anxieties) but the vividness of your night visions is related to the quality of sleep, and it’s that which progesterone can affect.
Credit: Getty
There are two ways that progesterone can fragment sleep, Dr Sharkey explains. During the luteal phase of the menstrual cycle – right after ovulation – progesterone levels increase, causing a higher core body temperature. “This can prompt arousals from sleep,” she says.
“Progesterone also acts on a receptor system called GABA, which is activated by things like sleep aids and alcohol. When progesterone levels are elevated, there may be an increase in fatigue and sleepiness during the day.” This is a symptom of PMT many of us will recognise (and dread). But when the progesterone levels then abruptly drop in the premenstrual or luteal phase of our cycle, we get a “withdrawal of activation” in the GABA system that can also cause sleep fragmentation, says Dr Sharkey.
Oestrogen
Although not the main offender, oestrogen fluctuations can also play a role in sleep quality and dream frequency, adds Dr Sharkey. She explains that there is research that associates oestrogen with better sleep but argues that “most of the data driving this generalisation comes from hormone replacement studies where participants were also experiencing hot flushes or other menopausal symptoms”. In other mammals, oestrogen promotes wakefulness and therefore could be a cause of sleep fragmentation near the time of ovulation, she suggests.
Oestrogen plays a role in dream frequency
Dr Katharine Sharkey
How do hormonal imbalances impact sleep and dream frequency?
Dr Sharkey’s research found that while most women with menstrual cycles don’t experience huge variations in sleep quality throughout the month, up to 15% have a hormone sensitivity. It’s also worth pointing out that at any one time, a huge proportion of us are living with hormonal issues like PCOS, endometriosis or fibroids – all of which directly impact our levels of oestrogen and progesterone. There’s plenty of evidence, for example, that women with PCOS are more at risk of sleep disturbances and disorders. And if you follow Dr Sharkey’s research, it seems fair to suggest that those of us with these issues may well remember our dreams better than those who enjoy a greater hormonal balance (and therefore sounder sleep).
“The impact of hormonal flux can result in profound dysregulation in these individuals,” says Dr Sharkey, adding that her recent research has determined that hormonal sensitivity is more common among women who also have depression or anxiety.
The hormonal fluctuations that come with pregnancy, perimenopause and menopause have also been shown to impact sleep. A Canadian study built around data from 6,796 pregnant women determined that nearly 50% of them experienced “short sleep” each term. That could be caused by several issues including overheating, discomfort and heartburn, but it’s a fact that oestrogen and progesterone levels both increase dramatically during pregnancy. As we head into perimenopause, on the other hand, those levels fluctuate and then decline. The dip in progesterone causes hot flushes, night sweats, mood changes and anxiety – none of which are conducive to a good night’s sleep. An analysis of hundreds of papers, found that more than half of women suffer from sleep disorders during menopause.
Sick of my own nightmare loop, I decided to track my dreams and quickly found that my issues were linked to my cycle. Having realised that, I’m now able to pay extra attention to preparing for a better night’s sleep on those weeks when I know that I might experience disruption and it’s helped. Simple things like ensuring that I’m going to bed when I’m tired, that my room is cool and dark and having a little wind-down time in the evening have made a massive difference.
But if you find that vivid dreams and nightmares are just one of a myriad of other hormonal symptoms you’re experiencing – or that your nightly visions and disrupted sleep are starting to impact your life quality – then it’s time to make an appointment with your GP. They can help you to work out if a hormone test might be useful, what interventions might be made to help rebalance out-of-kilter hormones or refer you to a sleep clinic.
Images: Getty
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