The reproductive period eventually slows and stops for women. This process starts to slow after puberty when ovulation and menstruation begin. As women age, their reproductive abilities shift over time until they end at menopause.
We will look at what menopause entails and the effects it can have on the body and brain.
What Is Menopause?
Menopause is a naturally occurring biological event that marks the end of a woman's fertility and reproductive abilities. It’s also the end of menstruation, as the ovaries will no longer produce an egg every four weeks. Menopause doesn’t technically begin until 12 consecutive months without a menstrual period.
Four distinct stages occur during menopause:
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Premenopause is when menstrual cycles are regular, and reproduction is possible. Each month, the ovaries take turns producing a mature egg (a process known as ovulation). The egg is then released into the fallopian tube, where it’s available to be fertilized by sperm.
- Perimenopause is when menstrual cycles start to become erratic. The ovaries begin to shrink, and the production of female hormones (estrogen and progesterone) declines. As a result, hormone levels can fluctuate, causing physical and mental side effects.
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Menopause is when menstrual cycles have officially ended, and reproduction is no longer possible. No menstruation has occurred for 12 consecutive months, and the ovaries can no longer produce new eggs each month.
- Postmenopause is after menopause and lasts for the remainder of life. Pregnancy is no longer possible as the ovaries stop releasing eggs. The production of estrogen and progesterone will often stabilize but may remain lower than premenopause.
What Causes Menopause?
Age is the most common cause of menopause and typically occurs between the ages of 45 and 55. It’s easiest to think of menopause as the opposite of puberty. Instead of ramping up to prepare for reproduction, the body is ramping down and “retiring” from its reproductive duties.
Most women typically start to experience declining estrogen and progesterone production levels sometime in their late 30s. These are the beginning stages of perimenopause, and production levels will continue to drop.
Additionally, each ovary has a finite number of primordial follicles (roughly 400,000). Each follicle contains a single oocyte. These immature egg cells (known as ovum) are grown and developed into mature eggs released during ovulation.
In most cases, a woman only has a maximum of 400 or 500 of these egg cells mature enough to be released during menstruation. The body will expel the uterine lining through menstruation if the egg is left unfertilized. Once the available eggs are gone, natural reproduction will no longer be possible.
Age is not the only potential cause of menopause. It’s possible to experience the process before entering the midlife stage.
The condition is known as premature menopause and can occur for a variety of reasons, including:
- A condition called premature ovarian failure
- Chemotherapy or radiation treatments that damage the uterus or ovaries
- Surgeries that remove the uterus or ovaries (hysterectomy, bilateral oophorectomy, etc.)
- Infections that damage the uterus or ovaries (shingles, malaria, tuberculosis, etc.)
- Diseases that can damage the uterus or ovaries (Down syndrome, Addison’s disease, Turner syndrome, etc.)
How Does Menopause Affect the Brain?
The human brain is a fascinating organ capable of incredible feats. Unfortunately, the female brain is not immune to the effects of menopause. The decrease in estrogen and progesterone production may be largely to blame for the cognitive changes associated with menopause.
The drop in production can cause a ripple effect in women’s brains, which can lead to symptoms including:
Hot Flashes/Night Sweats
Perhaps the most notorious symptoms of menopause are hot flashes and night sweats. Estrogen helps activate the hypothalamus, which is crucial in regulating body temperature. Having less estrogen in the brain can impair the hypothalamus from functioning properly, making it more sensitive to changes in body temperature.
As a result, the hypothalamus often perceives internal body temperature as higher than it actually is. Hot flashes try to cool the body down, usually resulting in excessive sweating and severe blushing in the upper body.
Memory Impairment
The hippocampus is the brain's memory center and relies heavily on estrogen to function properly. The fluctuations of estrogen levels during menopause can impact the hippocampus and cause issues with memory. Specifically, it appears to affect the memory of words.
Delayed verbal memory, slower verbal processing speeds, and impaired verbal learning can all be common side effects of menopause (sometimes referred to as “menopause brain”). For example, recalling words on a grocery list and remembering actors' names can suddenly become extremely difficult.
Fortunately, these effects on cognitive function aren’t usually permanent, and memory loss often resolves post-menopause. Performing brain exercises during menopause can also help to maintain memory skills.
Mood Swings
The amygdala is located near the hippocampus and is the brain's emotional center. As estrogen is the primary sex hormone in women, it makes sense that the amygdala is loaded with estrogen receptors.
Fluctuating levels of estrogen can disrupt the production of serotonin, otherwise known as the “feel good” hormone. Feelings of irritability, anxiety, and depression can appear from nowhere and be difficult to manage.
It’s common for cortisol (the primary stress hormone) levels to increase, worsening these negative emotions. Eating foods that boost serotonin production can help to stabilize these mood swings.
Energy Metabolism
Glucose (more commonly known as blood sugar) is the primary energy source for the brain. Estrogen plays an essential role in how the brain metabolizes glucose. The brain often becomes less efficient at using glucose, naturally resulting in reduced brain activity.
Even slight energy reductions can have an effect on the brain. The flow of blood (which carries oxygen and essential nutrients) can slow down. Electrical activity can decline, meaning neurons communicate less efficiently with other neurons. These effects can compound and result in another common symptom of menopause: shrinkage.
Brain Shrinkage
The brain comprises two types of matter: gray matter (40 percent) and white matter (60 percent). Gray matter is found throughout the central nervous system, allowing people to control movement, memory, and emotions.
It’s common for gray matter to shrink inside the brain due to menopause. The disruption in energy metabolism may be one of the primary reasons for this issue. It’s common for gray matter shrinkage to result in cognitive decline as the cells within the gray matter lose function.
The good news is that gray matter volume usually returns to normal in key brain regions for post-menopausal women.
Sleeping Disorders
Falling asleep slowly, waking up often, restless leg syndrome, sleep apnea, and periodic leg movement syndromes can all be common disorders associated with menopause. There are several reasons why sleeping can become a challenge during menopause, but the primary one deals with ovarian hormones.
Optimal estrogen and progesterone levels can support a night of restful sleep. Having too much or too little of these hormones can greatly impact sleep. Since menopause is marked by intense fluctuations in these hormones, difficulties with sleeping can be very common.
Increased Risk of Developing Certain Medical Conditions
Clearly, a lot of changes occur during menopause. The good news is that the brain can adapt to the new levels of ovarian hormones, and things largely return to normal. The bad news is that sometimes the damage done during menopause can have permanent effects.
Here are a few examples of medical conditions that can become more likely during menopause:
- Hormonal imbalances during menopause can result in weight gain and cause blood pressure to become more sensitive to salt. These effects can result in higher blood pressure and elevated blood lipid levels, increasing the risk of stroke and heart attack.
- The accumulation of body fat often accelerates during menopause, and fluctuations can occur in adrenal and thyroid hormone secretions. The combination of these two factors can increase insulin resistance in menopausal women.
- Menopause can lead to an increased accumulation of beta-amyloid peptides. When these deposits start to clump together, it can result in the development of plaques in the brain. These abnormal plaques can build up in and around brain cells and are the primary cause of Alzheimer’s disease.
Can Menopause Be Treated?
Menopause is a natural part of life, so getting through it without requiring special treatment is possible. Most of the time, symptoms will be dealt with individually as they appear.
However, there are some cases where the symptoms can be particularly intense. A physician may recommend undergoing hormone replacement therapy to help alleviate these cases.
Hormone replacement therapy (HRT) entails using female hormones such as estrogen and progesterone to stabilize declining levels and prevent fluctuations. The symptoms of menopause are typically reduced but likely won’t entirely disappear.
Hormones can be administered via tablet, topical cream/gel, injection, skin patch, or implant. Hormone replacement therapy typically ends when hormone levels stabilize during the postmenopausal stage.
The symptoms of menopause can also be lessened by making a few lifestyle changes:
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Eating a well-balanced dietfeaturing foods that support brain function may help to maintain cognitive abilities during menopause. Most experts recommend following the Mediterranean Diet for best results. However, eating more cruciferous vegetables, dairy products, berries, whole grains, and water might help alleviate some symptoms.
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Physical exercise can support brain health and might reduce the severity of some symptoms. Cardio is one of the most recommended exercises for menopause but stretching, muscle strengthening, and relaxation techniques can also be helpful.
- Lowering your stress levels might be challenging during menopause, but it’s likely to help reduce the severity of symptoms. Frequently experiencing stress can be harmful at any point during life and can worsen menopause symptoms.
Take Care of Your Brain As It Adjusts
It’s no secret that getting older can feel challenging. Menopause is one of these changes that all women will experience at some point. It’s never too soon to start preparing your brain for the effects of menopause.
The good news is that life post-menopause often returns to some degree of normal. The brain usually adapts to having a lower level of estrogen and progesterone.
The primary concern while experiencing menopause is often avoiding Alzheimer’s. Roughly 82 percent of women are unaware of their increased risk of developing Alzheimer’s. It’s never too soon to start taking steps to prevent the development of this incurable and frequently fatal disease.
Sources:
Hormone Replacement Therapy | NCBI Bookshelf
What is Alzheimer's Disease? Symptoms & Causes | alz.org
Menopause and high blood pressure: What's the connection? | Mayo Clinic
Sleep Disorders and Menopause | PMC
The Cerebellum and White and Gray Matter | My-MS.org
Uncovering the Mechanisms of Estrogen Effects on Hippocampal Function | PMC
A Neural Circuit Underlying the Generation of Hot Flushes | PMC
NIH-Funded Researchers Generate Mature Egg Cells From Early Ovarian Follicles | NIH
What Is Menopause? | National Institute on Aging