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Why Does Sex Make Men Sleepy?

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Alfred Kinsey, biologist, pioneering sex researcher and founder of the Institute for Sex Research at Indiana University*, once wrote that "a marked quiescence of the total body is the most widely recognized outcome of orgasm," more noticeably among males. Why is that?

Let's get the obvious reasons out of the way first. Sex often, though not always, happens at night in a bed and is physically exhausting. If you're tired to begin with, all that physical exertion only adds to it, and since you're already in bed, it's only natural to be sleepy. Compounding this is the fact that sex dominates your attention when you're having it (and sometimes when you're not), so you don't pay attention to your breathing and wind up breathing shallowly and holding your breath pretty often. These aren't really the sorts of things you want to do during vigorous exercise, as they lead to oxygen deprivation and—all together now—sleepiness.

There's also the biochemistry of the orgasm to consider.

After sex, a man's brain releases a slew of hormones and neurotransmitters. Some of them, like prolactin, oxytocin and vasopressin, have been linked to sleep as well as sex. Prolactin plays a role in sexual satisfaction by counteracting the effects of dopamine** (which is responsible for sexual arousal). It's also been shown that the artificial delaying of an REM sleep period disrupts the rhythm of prolactin release, and that REM sleep is reduced in mice with prolactin deficiencies. Oxytocin and vasopressin have also both been implicated in the body's regulation of sleep cycles. While none of these chemicals are fully understood and their links to sleep aren't concrete, the circumstantial evidence suggests that they may play a part in pulling you off to a post-coital snooze.

What About the Ladies?

The phenomena of men falling asleep soon after sex is a little more well established than women doing the same—at least in that people notice it enough to make jokes about it on sitcoms, and write in to mental_floss asking about it. While I haven't been able to find any science-backed evidence that post-sex sleepiness definitively affects men more than women, there are a few hypotheses floating around as to why it seems that way. In their 2006 book Why Do Men Fall Asleep After Sex?, Mark Leyner and Billy Goldberg, M.D. suggest that exertion during sex depletes the muscles of energy-producing glycogen. Because men usually have more muscle mass, they get more tired. And it's entirely possible that women get just as sleepy, just as fast as men do after orgasm, but women simply have orgasms during sex less often than men do.

*Kinsey left his mark on a different field earlier in his career: entomology. He did his doctoral thesis on gall wasps and researched and published papers about them at the American Museum of Natural History in New York. Of the 18 million+ insects in the museum's collections, about 5 million are gall wasps that Kinsey collected. In return for his collection, Kinsey received $400 and a lifetime membership to the Museum.

**The hormone may also mediate the "sexual refractory period," or the recovery phase after an orgasm during which a man cannot have additional orgasms or achieve an erection.

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Why You Should Think Twice About Drinking From Ceramics You Made by Hand
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Ceramic ware is much safer than it used to be (Fiesta ware hasn’t coated its plates in uranium since 1973), but according to NPR, not all new ceramics are free of dangerous chemicals. If you own a mug, bowl, plate, or other ceramic kitchen item that was glazed before entering the kiln, it may contain trace amounts of harmful lead.

Earthenware is often coated with a shiny, ceramic glaze. If the clay used to sculpt the vessel is nontoxic, that doesn’t necessarily mean the glaze is. Historically, the chemical has been used in glazes to give pottery a glossy finish and brighten colors like orange, yellow, and red.

Sometimes the amount of lead in a product is minuscule, but even trace amounts can contaminate whatever you're eating or drinking. Over time, exposure to lead in small doses can lead to heightened blood pressure, lowered kidney function, and reproductive issues. Lead can cause even more serious problems in kids, including slowed physical and mental development.

As the dangers of even small amounts of lead have become more widely known, the ceramics industry has gradually eliminated the additive from its products. Most of the big-name commercial ceramic brands, like Crock-Pot and Fiesta ware, have cut it out all together. But there are still some manufacturers, especially abroad, that still use it. Luckily, the FDA keeps a list of the ceramic ware it tests that has been shown to contain lead.

Beyond that list, there’s another group of products consumers should be wary of: kiln-baked dishware that you either bought from an independent artist or made yourself. The ceramic mug you crafted at your local pottery studio isn’t subject to FDA regulations, and therefore it may be better suited to looking pretty on your shelf than to holding beverages. This is especially true when consuming something acidic, like coffee, which can cause any lead hiding in the glaze to leach out.

If you’re not ready to retire your hand-crafted ceramic plates, the FDA offers one possible solution: Purchase a home lead testing kit and analyze the items yourself. If the tests come back negative, your homemade dishware can keep its spot on your dinner table.

[h/t NPR]

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Marathon Running Won't Undo Poor Lifestyle Choices, Study Suggests
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Even marathon participants can't outrun an unhealthy lifestyle, according to a new study highlighted by The New York Times.

For years, expert opinion has been mixed on whether long-distance running helps or hurts hearts. In the 1970s, research suggested that marathon running and a heart-healthy diet would completely prevent atherosclerosis (a buildup of harmful plaque in the arteries). But since high-profile runners have died of heart attacks, scientists in the 1980s began to worry that running might actually harm the vital organ. Compounding this fear in recent years were studies suggesting that male endurance athletes exhibited more signs of heart scarring or plaques than their less-active counterparts.

Experts don't have a verdict quite yet, but researchers from the University of Minnesota and Stanford and their colleagues have some good news—running doesn't seem to harm athletes' hearts, but it's also not a panacea for heart disease. They figured this out by asking 50 longtime marathon runners, all male, with an average age of 59, to fill out questionnaires about their training, health history, and habits, and then examining them for signs of atherosclerosis.

Only 16 of the runners ended up having no plaque in their arteries, and the rest exhibited slight, moderate, or worrisome amounts. The men who had unhealthy hearts also had a history of smoking and high cholesterol. A grueling training regime seemed to have no effect on these levels.

Bottom line? Marathon running won't hurt your heart, but it's not a magic bullet for poor lifestyle choices.

[h/t The New York Times]

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