Why Do I Wake Up Right Before My Alarm Goes Off?

Because your body’s internal clock is just as good, if not better, than the contraption shrieking atop your nightstand.  

At the center of your brain, a clump of nerves—called the suprachiasmatic nucleus—oversees your body’s clock: the circadian rhythm. It determines when you feel sleepy and when you feel bright-eyed. It controls your blood pressure, your body temperature, and your sense of time. It turns your body into a finely tuned machine.

That machine happens to love predictability. Your body is most efficient when there’s a routine to follow. So if you hit the hay the same time each night and awake the same time each morning, your body locks that behavior in. And that’s where things get sciency.

Beat the clock!

Your sleep-wake cycle is regulated by a protein called PER. The protein level rises and falls each day, peaking in the evening and plummeting at night. When PER levels are low, your blood pressure drops, heart rate slows, and thinking becomes foggier. You get sleepy.

If you follow a diligent sleep routine—waking up the same time every day—your body learns to increase your PER levels in time for your alarm. About an hour before you’re supposed to wake up, PER levels rise (along with your body temperature and blood pressure). To prepare for the stress of waking, your body releases a cocktail of stress hormones, like cortisol. Gradually, your sleep becomes lighter and lighter. 

And that’s why you wake up before your alarm. Your body hates your alarm clock. It’s jarring. It’s stressful. And it ruins all that hard work. It defeats the purpose of gradually waking up. So, to avoid being interrupted, your body does something amazing: It starts increasing PER and stress hormones earlier in the night. Your body gets a head start so the waking process isn’t cut short. It’s so precise that your eyelids open minutes—maybe even seconds—before the alarm goes off.

You snooze, you lose

There’s evidence you can will yourself to wake on time, too. Sleep scientists at Germany’s University of Lubeck asked 15 volunteers to sleep in their lab for three nights. One night, the group was told they’d be woken at 6 a.m., while on other nights the group was told they’d be woken at 9 a.m..

But the researchers lied—they woke the volunteers at 6 a.m anyway. And the results were startling. The days when sleepers were told they’d wake up early, their stress hormones increased at 4:30 a.m., as if they were anticipating an early morning. When the sleepers were told they’d wake up at 9 a.m., their stress hormones didn’t increase—and they woke up groggier. “Our bodies, in other words, note the time we hope to begin our day and gradually prepare us for consciousness,” writes Jeff Howe at Psychology Today.

Incidentally, if you don’t wake before your alarm, you probably aren’t getting enough sleep—or you aren’t sleeping on a consistent schedule. Waking up at different times on weekdays and weekends can quickly throw your clock out of whack. Without any consistency, your body may not know when to get up. So when your alarm starts screaming, you feel dazed and grumpy.

Enter the snooze button. Since your body’s gone through all that work to rise gradually, a quick nap sends your internal clock spinning in the wrong direction. All the hormones that help you fall asleep meddle with the hormones that help you wake up. Your body gets confused. You feel groggier. And with each slap of the snooze, it gets worse. The snooze, it seems, is the worst way to start your day.

What's That Thing That Hangs Off a Turkey’s Face?

NCHANT/iStock via Getty Images
NCHANT/iStock via Getty Images

That thing is called a snood. And it's there to let the other turkeys know that its owner is kind of a big deal.

When a male turkey—known as a tom—wants to mate, he faces two hurdles. One is his potential mates, the female turkeys (a.k.a. hens). In the realm of turkey mating, the hens wield the power of choice and the toms have to get a hen's attention and win the opportunity to reproduce. Come mating season, a tom will strut around, gobble, puff out his chest, fan his tail, and drag his wings to attract the hens, who then pick which of the toms they’ll mate with.

The second problem for a tom looking for love is the other toms in the area. They’re all competing for the same limited number of hens. Sometimes a good mating display isn’t enough to win a mate, and toms will attack and fight each other to secure a hen.

This is where the snood comes in. That goofy-looking piece of dangling flesh helps a tom both with choosy hens and with competition from rival males. Having a long snood almost always means that a hen will want to mate with him and that another tom will back down from a fight.

Dudes and their snoods

When two toms are trying to establish dominance, they’ll size each other up. Then they'll either fight, or one will flee.

In the late 1990s, Dr. Richard Buchholz, an animal behaviorist who focuses on turkeys, wanted to figure out which, if any, characteristics of a tom turkey could predict how they fare in dominance fights. That is, did bigger turkeys tend to win more scuffles? Did older ones? He also wanted to see if the turkeys used any of these predictive cues when sizing each other up. He looked at various characteristics of dominant toms that fight and win, and compared them to those of subordinate toms that lose fights or run from them. Of all the characteristics he looked at, only “relaxed snood length” seemed to be a reliable predictor of how a tom would do in bird-vs-bird combat. The dominant males, the ones who won fights and got a choice mate, had longer snoods.

With that in mind, Buchholz looked at how toms reacted to other toms with snoods of varying sizes. The birds tended to avoid confrontation with other males with longer snoods, and wouldn’t even feed near them. A big snood, this suggests, says to the other turkeys that this is a tom you don’t want to tangle with. Buchholz noted that snood length correlates with age, body mass, and testosterone, so, to competitors, the snood could be a good indicator of a tom’s aggressiveness, age/experience, size, and overall condition and fighting ability.

In the snood for love

Once the males have established who’s going to have a chance to mate, the final choice goes to the hen. While the mating display is the main draw for getting a hen to check him out, a tom’s snood helps him out again here.

Like it did for the other males, a tom’s snood signals a lot of information to a female assessing potential mates—it indicates how old and how big he is, and even says something about his health. In another study, Buchholz found that longer-snooded toms carried fewer parasites. If a hen wanted to choose a mate with good genes that might help her offspring grow large, live long, and avoid parasites, a tom’s snood is a good advertisement for his genes. In that study, hens showed a clear preference for toms with longer snoods. In another experiment years later, Buchholz found that healthy hens again showed a strong preference for long snoods and that hens with their own parasite problems were less picky about snood length and checked out more potential mates—perhaps, Buchholz thinks, because the hens recognized their own susceptibility to infection and were willing to invest more time searching for a tom with genes for parasite resistance that would complement their own—but still showed some preference for longer ones.

While a snood might look goofy to us, for a turkey, it’s integral to the mating game, signaling to other toms that they should get out of his way and letting hens know that he’s got what they’re looking for.

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What's the Difference Between Yams and Sweet Potatoes?

Julia_Sudnitskaya/iStock via Getty Images
Julia_Sudnitskaya/iStock via Getty Images

This Thanksgiving, families across the country will enjoy a traditional meal of turkey, stuffing, and sweet potatoes ... or are they yams? Discussions on the proper name for the orange starchy stuff on your table can get more heated than arguments about topping them with marshmallows. But there's an easy way to tell the difference between sweet potatoes and yams: If you picked up the tuber from a typical American grocery store, it's probably a sweet potato.

So what's a sweet potato?

Sweet potato and yam aren't just different names for the same thing: The two produce items belong to their own separate botanical categories. Sweet potatoes are members of the morning glory family. Regular potatoes like russets, meanwhile, are considered part of the nightshade family, which means that sweet potatoes aren't actually potatoes at all.

Almost all of the foods most Americans think of as yams are really sweet potatoes. The root vegetable typically has brown or reddish skin with a starchy inside that's orange (though it can also be white or purple). It's sold in most supermarkets in the country and used to make sweet potato fries, sweet potato pie, and the sweet potato casserole you have at Thanksgiving.

Then what's a yam?

Yams.
Yams.
bonchan/iStock via Getty Images

Yams are a different beast altogether. They are more closely related to lilies and grasses and mostly grow in tropical environments. The skin is more rough and bark-like than what you'd see on a sweet potato, and the inside is usually white or yellowish—not orange.

They're a common ingredient in parts of Asia, Africa, and the Caribbean. Because the inside of a yam is less moist than the inside of a sweet potato, they require more fat to make them soft and creamy. They're also less sweet than their orange-hued counterparts. In many regions in the U.S., yams aren't sold outside of international grocery stores.

Where did the mix-up come from?

Also sweet potatoes.
Also sweet potatoes.
Kateryna Bibro/iStock via Getty Images

So if yams and sweet potatoes are two totally different vegetables that don't look or taste that similar, why are their names used interchangeably in the U.S.? You can blame the food industry. For years, "firm" sweet potatoes, which have brown skin and whitish flesh, were the only sweet potatoes grown in the U.S. In the early 20th century, "soft" sweet potatoes, which have reddish skin and deep-orange flesh, entered the scene. Farmers needed a way to distinguish the two varieties, so soft sweet potatoes became yams.

Nearly a century later, the misnomer shows no signs of disappearing. Many American supermarkets still call their orange-fleshed sweet potatoes yams and their white-fleshed ones sweet potatoes, even though both items are sweet potatoes. But this isn't a strict rule, and stores often swap the names and make things even more confusing for shoppers. So the next time you're shopping for a recipe that calls for sweet potatoes, learn to identify them by sight rather than the name on the label.

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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