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Do Men Have a Monthly Hormone Cycle?

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It’s well established that women undergo a monthly menstrual cycle that includes fluctuations in hormones, and eventually a cease to these cycles at menopause. While there are numerous jokes about male “manstruation” and “manopause,” mental_floss spoke with two experts in male endocrinology and fertility—Paul Marshburn, a reproductive endocrinologist at Carolinas HealthCare System in North Carolina, and Brad Anawalt, an endocrinologist and chief of medicine at University of Washington Medical Center—to answer the question: Do men undergo a similar hormone cycle?

Despite one researcher’s controversial theory that men do have a monthly cycle (his results were never replicated), the short answer is almost certainly no, men do not experience a cyclical hormone shift on a monthly basis. Instead, they experience a daily (or diurnal) rise and fall of the most prominent hormone in their bodies, testosterone (T). While male bodies also produce a form of estrogen called estradiol (largely through a process that converts testosterone into estradiol), testosterone is either directly or indirectly the key to many health functions in their bodies, responsible for regulating sex drive (libido), bone mass, fat distribution, muscle mass and strength, and producing red blood cells and sperm. For men in good to average health, testosterone levels are highest in the morning hours, which cause morning erections, and increased energy and vitality. Testosterone levels then slowly drop as the day goes on and are at their lowest at the end of the day and evening. Because of this, men should get blood testosterone levels checked in the morning hours for an accurate baseline.

Certain activities can cause fleeting spikes of testosterone during the day, such as intense exercise or sexual activity. Likewise, stress and illness can cause sudden drops in testosterone in a given day. Levels also decline naturally over the course of a man’s life as he ages; his testosterone levels begin to drop as early as age 30 between 0.5 and one percent below his baseline per year.

Other causes for drops in testosterone include illness, from the seasonal flu to significant diseases like diabetes or cancer, since the body’s need to conserve energy often reduces the need to produce sperm or have sex. Some research points to seasonal sources of spikes and surges in testosterone, particularly in countries that experience longer than usual light and dark cycles, like Finland or Norway, where testosterone levels bottom out in summer and reach a high in late fall. Eating disorders and lack of sleep can also effect testosterone levels and sperm production.

Testosterone therapy to replace normal, age-related declines is a growing area of treatment. The research body on this is small, but a 2016 New England Journal of Medicine study found conclusively that testosterone therapy in men ages 65 and over improved sexual function and libido.

Loss of testosterone leads to a reduction in sexual arousal, decreased ability to achieve an erection, and loss of muscle mass and tone and bone marrow and density. More research has also found that low estradiol levels in aging men may be linked to cardiovascular disease and heart failure.

Ultimately, the best way for men to keep their testosterone at normal levels is to engage in healthy lifestyle behaviors such as exercise and healthy eating, and to keep to a minimum opioid medications, alcohol and smoking.

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Big Questions
What is Duck Sauce?
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A plate of Chinese takeout with egg rolls and duck sauce
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We know that our favorite Chinese takeout is not really authentically Chinese, but more of an Americanized series of menu options very loosely derived from overseas inspiration. (Chinese citizens probably wouldn’t recognize chop suey or orange-glazed chicken, and fortune cookies are of Japanese origin.) It would also be unusual for "real" Chinese meals to be accompanied by a generous amount of sauce packets.

Here in the U.S., these condiments are a staple of Chinese takeout. But one in particular—“duck sauce”—doesn’t really offer a lot of information about itself. What exactly is it that we’re pouring over our egg rolls?

Smithsonian.com conducted a sauce-related investigation and made an interesting discovery, particularly if you’re not prone to sampling Chinese takeout when traveling cross-country. On the East Coast, duck sauce is similar to sweet-and-sour sauce, only fruitier; in New England, it’s brown, chunky, and served on tables; and on the West Coast, it’s almost unheard of.

While the name can describe different sauces, associating it with duck probably stems from the fact that the popular Chinese dish Peking duck is typically served with a soybean-based sauce. When dishes began to be imported to the States, the Americanization of the food involved creating a sweeter alternative using apricots that was dubbed duck sauce. (In New England, using applesauce and molasses was more common.)

But why isn’t it easily found on the West Coast? Many sauce companies are based in New York and were in operation after Chinese food had already gained a foothold in California. Attempts to expand didn’t go well, and so Chinese food aficionados will experience slightly different tastes depending on their geography. But regardless of where they are, or whether they're using the condiment as a dipping sauce for their egg rolls or a dressing for their duck, diners can rest assured that no ducks were harmed in the making of their duck sauce.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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Big Questions
Can You Really Go Blind Staring at a Solar Eclipse?
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A total solar eclipse will cut a path of totality across the United States on August 21, and eclipse mania is gripping the country. Should the wide-eyed and unprotected hazard a peek at this rare phenomenon?

NASA doesn't advise it. The truth is, a quick glance at a solar eclipse won't leave you blind. But you're not doing your peepers any favors. As NASA explains, even when 99 percent of the sun's surface is covered, the 1 percent that sneaks out around the edges is enough to damage the rod and cone cells in your retinas. As this light and radiation flood into the eye, the retina becomes trapped in a sort of solar cooker that scorches its tissue. And because your retinas don't have any pain receptors, your eyes have no way of warning you to stop.

The good news for astronomy enthusiasts is that there are ways to safely view a solar eclipse. A pair of NASA-approved eclipse glasses will block the retina-frying rays, but sunglasses or any other kind of smoked lenses cannot. (The editors at MrEclipse.com, an eclipse watchers' fan site, put shades in the "eye suicide" category.) NASA also suggests watching the eclipse indirectly through a pinhole projector, or through binoculars or a telescope fitted with special solar filters.

While it's safe to take a quick, unfiltered peek at the sun in the brief totality of a total solar eclipse, doing so during the partial phases—when the Moon is not completely covering the Sun—is much riskier.

WOULDN'T IT BE EASIER TO JUST TELL YOUR KIDS THEY WILL GO BLIND?

NASA's website tackled this question. Their short answer: that could ruin their lives.

"A student who heeds warnings from teachers and other authorities not to view the eclipse because of the danger to vision, and learns later that other students did see it safely, may feel cheated out of the experience. Having now learned that the authority figure was wrong on one occasion, how is this student going to react when other health-related advice about drugs, alcohol, AIDS, or smoking is given[?]"

This story was originally published in 2012.

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