Why is it harder to keep my weight down? Where did my waist go? Where did my sex drive go? Are my periods supposed to be heavier? What happened to natural regularity?
These are common complaints of women in their 40s. Are they simply a function of age? Does this “in-between decade” that occurs after most of us have had our babies, used contraception and practiced safe sex (in our 30s) constitute a dress rehearsal for menopause? Here are some answers about our body changes during this decade.
Let’s start with _our hormones. Are there major changes in our 40s?
A. Yes. During this decade, our ovaries are producing hormones through what I call "follicular rejects." We start out with 1 million to 2 million pre-eggs (oocytes), at birth. Most of these die before we even reach puberty, at which time we're down to a paltry 400,000. Over the next 25 years, unless we're pregnant or on birth-control pills, one of these oocytes develops within a mature follicle that initially produces estrogen and after two weeks releases the egg (ovulation) and produces estrogen and progesterone. For every oocyte that comes to fruition each month, thousands die, and this relentless path of death and destruction leaves us with fewer, and "less youthful" oocytes in our 40s. They are less likely to fully develop into hormonally competent follicles that can secrete adequate amounts of estrogen and progesterone than those we had in our 20s and 30s.
The oocytes that have not died and have been waiting around for four decades are also extremely vulnerable to chromosomal tears, breaks and misinformation, so they are also less likely to be capable of releasing an egg that can successfully become fertilized, and subsequently produce a viable embryo. This explains why fertility rates, (both natural and those subsequent to high-tech reproductive assistance) plummet in our 40s. "Reproductive menopause" can occur 10 years before true menopause (at which time virtually no productive follicles are left and estrogen and progesterone cannot be produced).
So how does this decrease in "good" follicles affect our cycle?
A. When a follicle develops poorly, it usually produces less hormone and may die off before its time, causing a menstrual period to occur sooner than usual; a 28-day cycle (counted from first day of one period to the first day of the next one), is now 24 days or less. If the diminished follicle produces too little estrogen, menopausal-type symptoms can occur even though you have your period. Scientists know that estrogen and progesterone affect the brain by altering levels of neurotransmitting substances; this, in turn, can have an affect on mood. As both estrogen and progesterone levels fall, especially at their nadir, or dip, just prior to and during your period, you may feel depressed, have hot flashes, night sweats and develop insomnia. During this period of low estrogen, you really can feel like you are experiencing a dress rehearsal for menopause.
With poor follicular development and low estrogen, your period may also "go missing." After a while, however, the hypothalamus in your brain may become activated because there's just too little estrogen in the neighborhood, so it stimulates pituitary production of FSH (Follicular Stimulating Hormones). This, in turn, can cause a bunch of residual follicles to develop, and a hormonal surge; excess amounts of estrogen then can cause pregnancy-like symptoms (breast tenderness and bloating). If at this time your hormone levels are checked, you would be told you are fine. A month later estrogen levels could plummet and you would then have an elevation of FSH. For some women these hormonal swings cause more symptoms (mood swings, intermittent hot flashes, breast tenderness, cycle changes, sleep disturbances and weight changes) and are more severe than those experienced in menopause.
So what is peri-menopause?
A. This is a time of irregular periods and symptoms due to fluctuating hormones. The peri-menopause transition can begin up to 10 years prior to menopause, but the usual duration is three or four years (note the average age of menopause is 51.3).
Why do so many women in their forties complain that their periods become heavier or more painful?
A. One of the most prevalent causes of heavy or painful periods as we get "older" (though I’m not suggesting we’re old in our 40s) is a condition called adenomyosis. Endometrial cells and glands grow into the uterine muscle wall, causing it to thicken. The glands prevent the muscle from properly contracting during the period and as a result the vessels running through the wall on their way to the lining (endometrium) are not properly squeezed shut, hence the period is heavy. The glands within the wall also swell and this generates pain.
As we enter our 40s, we are also more likely to develop fibroids. (These benign growths are found by ultrasound in up to 50 percent of women over the age of 35.) Those that grow in the wall of the uterus (intramural fibroids), like adenomyosis, prevent the vise-like action of the uterine muscles from "doing their thing" to stop bleeding. Fibroids also have their own blood supply which can contribute to heavy bleeding. And finally, fibroids that grow into the lining or cavity of the uterus (submucosal fibroids) can bleed between and during periods.
Do changes in our ovaries also cause changes in sex drive?
A. Libido is governed by many factors and can diminish from fatigue, stress, depression, medications, partner problems and self-image (the latter is often damaged by the societal concept that we are only sexy when we’re young). But hormones do play a part and although there is still a lot of controversy as to which hormones do what, lack of male hormones seems to decrease sexual desire. Male hormones come from both our adrenal glands and ovaries, and by our forties, the adrenal portion decreases by as much as fifty percent. But this is probably the least likely reason that women in their forties complain of diminished libido. It’s more probable that the above-mentioned factors are the "de-sexual" culprits.
What about weight issues in our 40s?
A. As we get older, our basal metabolic rate (which constitutes 60 percent to 70 percent of our daily calorie expenditure) decreases by 4 percent to 5 percent with each decade. This translates to about a hundred calories a day. What this means is, if we don't consume a hundred calories less or burn a hundred calories more a day (and the usual complaint is: Hey, I didn't change my diet and I’m still gaining weight.), this equates to a 10-pound-a-year weight gain!
Most of us, unfortunately, become less physical in our 40s, and to add hormonal insult to poundage, as our hormone levels fluctuate and then decline, we lose lean (muscle) body mass. Fat replaces muscle and since fat doesn't metabolize calories as well as muscle, the unused calories get deposited in our bodies; with age, that depository becomes the abdominal area. The result: loss of waist and protruding tummy … and there go our low-cut jeans. Before you mourn each birthday as a weight-day, know that you can prevent much of this with exercise and diminished caloric intake. Remember, just abstain from just one cookie a day and you may decrease your caloric intake by 100 calories.
Are other glands and organs changing in our 40s?
A. I know it sounds like much of what happens to our bodies in our 40s is due to changes in our reproductive system, but other glands and systems are also changing:
- Immunological changes - Your 40s (and future decades) tax the immune integrity of your thyroid which controls your metabolism. You are more likely to develop hypothyroidism (another cause for weight gain). If you've been gaining weight, your pancreas literally has had to work its tail off to make more insulin. Excess insulin increases fat production, especially fatty substances that are bad for your heart. If at some point your pancreas can’t keep up and blood sugars rise, you’ve developed Type 2 diabetes.
- Gastrointestinal - Your GI tract has been put through a lot in the last 40 years. The bowel lining resurfaces itself every 24 to 72 hours. In your 40s, your bowel may begin to show wear and tear. You’re more likely to develop lactose intolerance and be unable to consume milk products without subsequent gas, bloating and diarrhea (25 percent of Caucasians and 80 percent of African American and Asian women develop lactose intolerance). The muscles that propel what you eat through your intestines may also lose their synchronicity. As a result, you may develop irritable bowel syndrome (diarrhea, constipation or both). You are also more likely to develop gallstones, which can cause nausea, pain and heartburn. This has been termed the f-disease, "f" standing for fat, fecund (pregnancy) and forty. Gallstones (cholelithiasis) and gallbladder inflammation (cholecysitis) reach a peak incidence of 20 percent in our 40s.
- Cardiovascular system - Although we are still less likely than men to have a heart attack (probably because we still produce estrogen), fatty plaque adherence to blood vessels (atherosclerosis) and a decrease in elasticity of the vessels (leading to hypertension), may get worse in your 40s.
- Bone loss - Once more, estrogen protects the bones from significant loss of bone density. However, bone mass is lost at a rate of one-half percent a year after the age of thirty. Smoking, inactivity, early menopause and poor calcium intake can hasten bone loss and subsequent development of osteoporosis.
After I've listed all of these body changes, I realize that I've made it seem as if we should get into "40 sticker shock." I’m not suggesting that any or all of the above-mentioned system and body changes will cause significant symptoms or health problems for every woman. However, understanding what happens and the changes that do occur during this decade may help you to take charge of your health and well being. Please talk to your doctor, get the right diagnostic tests, and make appropriate changes in your behavior, activity and if necessary, your medications ... so that you can get the most out of this decade and the next half of your life.
Dr. Judith Reichman, the TODAY show's medical contributor on women's health, has practiced obstetrics and gynecology for more than 20 years. You will find many answers to your questions in her latest book, "Slow Your Clock Down: The Complete Guide to a Healthy, Younger You," which is now available in paperback. It is published by William Morrow, a division of HarperCollins.
PLEASE NOTE: The information in this column should not be construed as providing specific medical advice, but rather to offer readers information to better understand their lives and health. It is not intended to provide an alternative to professional treatment or to replace the services of a physician.