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Whether you sat through awkward health classes in school or were lucky enough to get the talk from your folks, most of us understand the basics of the reproductive system: It subjects us to the emotional and physical upheaval that is puberty, and it’s how we make babies. Testes in men make sperm, ovaries in women make eggs, and both organs produce sex hormones that help the sperm and egg get together.
Recent advances in fertility science mean we know more than ever about how sex hormones contribute to conception and pregnancy. In 2014, for example, researchers discovered that progesterone released by the egg activates a stronger tail flick in sperm so it can penetrate the egg.
But fertility is just one part of a bigger picture. Our reproductive organs and the hormones they produce are just as important for our everyday health and performance. In this article, we’ll look at the three main sex hormones: estrogen, testosterone and progesterone.
Estrogen is actually a group of three very similar hormones: estrone, estradiol and estriol. It’s important for both men and women, though women have significantly higher amounts than men in the years between puberty and menopause. During this time, most of a woman’s estrogen is produced in her ovaries.
The changing hormones of the menstrual cycle means that a woman’s estrogen levels are relatively low when she has her period, rise to a relatively high level until ovulation, and fall again before her next period. Pregnancy, of course, changes everything, and so does menopause, when the ovaries stop making eggs or estrogen (and progesterone).
Estrogen promotes growth of the endometrium (the lining of the uterus), until it is countered by a rise in progesterone. It is important for circulation, tissue health, and lubrication of the vagina and vulva. Postmenopausal women often suffer from vaginal dryness because of their low levels of estrogen.
We often think of estrogen as the female hormone, but the average man’s estrogen levels are twice as high as those of a woman who has finished menopause. Men make most of their estrogen from testosterone, in the testes, where estrogen helps make sperm.
In both sexes, estrogen plays a role in literally hundreds of processes that keep us healthy. Bone health, good cholesterol, brain function, blood clotting, lung function, glucose metabolism, vascular function, heart health and muscle health all depend on the right level of estrogen.
Other weird and wonderful discoveries about estrogen include the following:
- Women’s higher estrogen levels increase sensitivity to the THC in cannabis—by 30 percent more than men.
- In a late 2017 paper, researchers at the University of Illinois at Chicago found that the relatively higher levels of estrogen during the pre-ovulatory part of the menstrual cycle were linked to increased alcohol sensitivity in the reward center of the brain.
- In 2016, mice studies suggested estrogen may be why the flu tends to hit men harder than women.
Testosterone is biosynthesized from cholesterol. In men, testosterone is made mostly in the testes. (Some is made in the adrenal glands, too.) It regulates lean mass, muscle size and strength, fat distribution and bone density. It also lowers asthma risk and helps the body make sperm.
Women produce small amounts of testosterone in their adrenal glands and ovaries, and it influences the follicle-stimulating hormones that trigger ovulation.
In both sexes, testosterone is important for muscle size and strength. It helps bone marrow to make red blood cells. The hormone hits a natural peak in our 30s, then decreases slightly every year as we age.
Testosterone levels in men are regulated by the hypothalamus in the brain and the pituitary gland. The hypothalamus sets the required level, and the pituitary signals the testes to make (or stop making) testosterone.
But it’s a sensitive system. A recently published study from the French Medical Research Council found that just two weeks of daily ibuprofen reduced testosterone production in a group of young, healthy test subjects.
And in 2011, researchers found that one week of poor sleep (five hours a night) was linked to a 10 to 15 percent decrease in testosterone levels.
Our bodies use progesterone to make estrogen, testosterone and many other hormones, like cortisol, in both women and men. But men only make about half as much progesterone as premenopausal women.
Progesterone and estrogen are intimately linked—each hormone balances the action of the other. For example, while estrogen encourages the endometrium to thicken, progesterone stops it from growing too much, and it may even help prevent endometrial cancer.
Healthy progesterone levels also seem to lower rates of estrogen-linked disorders such as premenstrual syndrome, depression and breast cancer.
Though men make much less progesterone, it’s important for spermiogenesis (one of the steps in sperm making) and sperm capacitation (the chemical/structural changes that enable the sperm to fertilize the egg). It also influences testosterone production in the testes, and it’s linked to better sleep in men.
In both sexes, progesterone helps prevent osteoporosis. Recent studies in mice have shown that progesterone reduces the severity of the flu.
A fine balance
All three sex hormones exist in a delicate balance. Too much or too little of any one of them can cause frustrating symptoms in the short term and chronic illness in the long term.
- High levels of estrogen can cause increased abdominal fat in men and weight gain in women. Prolonged exposure increases risk of breast cancer in both sexes.
- Low testosterone in men has become a prominent concern in recent years. Short-term issues include loss of muscle mass and strength, disrupted sleep and erectile dysfunction. Long-term “low-T” puts men at higher risk of developing Type 2 diabetes and osteoporosis.
- Women with higher than normal progesterone may experience breast tenderness, bloating and mood swings. Over time, they have an increased risk of ovarian cysts.
Regulating, balancing and fixing perceived hormonal imbalances has become big business. Natural and synthetic versions of sex hormones are available in creams, gels, pills and injections—not to mention the zillions of herbs and supplements that promise to naturally boost, control and support hormone health.
It’s more than a little confusing. The best bet is to consult with your trusted health-care provider, who can help you test for hormonal imbalances and guide you through treatment options. Because sex hormones have such a wide-ranging effect on our health, getting professional advice is a must.
Movement is maintenance
Exercise is a natural way to help regulate all our hormones at once. Regular workouts will …
- Boost estrogen levels up if they are low or bring levels down if you’ve been making too much.
- Improve testosterone levels. The stress on muscle fibers from resistance training triggers the production of anabolic hormones (for muscle repair and growth), including testosterone.
- Normalize progesterone levels. Moderate exercise is the key for this hormone: Do two to three days of weight training or moderate aerobics every week.
Excessive exercise will create too much stress in the body for any of your hormones, so make sure you get the dose just right for your best hormonal health.
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