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Why Can't I Sleep In On Weekends Anymore?

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Sleeping in is one of the best parts of the weekend. After a long, exhausting work week, sometimes all you want to do is sleep. On Friday night, you slide under the covers, smiling in anticipation. Now you can finally catch up on your sleep.

Except you can’t. When you open your eyes Saturday morning, it’s still early. If this were a weekday, you’d be up before your alarm. So what’s the deal? 

We hate to break it to you, but you’ve pretty much done this to yourself. Your body is very good at recognizing patterns and adjusting accordingly. If you’ve got a 9-to-5 job, you’re getting up early five days a week. This effectively sets your body clock to wake you at a certain time each day.

Waking up may feel instantaneous, but it’s actually a pretty gradual process. About an hour before you wake, your blood pressure and body temperature rise, as do levels of stress hormones like cortisol. Minute by minute, you become more alert until you’re completely awake. You can shut off your alarm clock, but your body clock will just keep ticking.

There’s another reason that you probably don’t want to think about: You’re just not as young as you used to be. We need less sleep as we get older. Babies need between 16 and 20 hours. Teenagers should (but often don’t) get nine hours a night. Younger and middle-aged adults need about eight hours of sleep a night. In general, the older you get, the harder it is to snooze the day away. 

Even if you do manage to sleep in, you may never fully catch up on your sleep. If your body needs eight hours every night and you only get six or seven from Monday to Friday, you’d have to sleep an extra five to ten hours on Saturday to make it up. And experts say even that may not be enough

The bottom line: Sleep when you can, and enjoy those extra weekend morning hours. Who doesn’t want a longer weekend?

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Ted Cranford
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Scientists Use a CT Scanner to Give Whales a Hearing Test
Ted Cranford
Ted Cranford

It's hard to study how whales hear. You can't just give the largest animals in the world a standard hearing test. But it's important to know, because noise pollution is a huge problem underwater. Loud sounds generated by human activity like shipping and drilling now permeate the ocean, subjecting animals like whales and dolphins to an unnatural din that interferes with their ability to sense and communicate.

New research presented at the 2018 Experimental Biology meeting in San Diego, California suggests that the answer lies in a CT scanner designed to image rockets. Scientists in San Diego recently used a CT scanner to scan an entire minke whale, allowing them to model how it and other whales hear.

Many whales rely on their hearing more than any other sense. Whales use sonar to detect the environment around them. Sound travels fast underwater and can carry across long distances, and it allows whales to sense both predators and potential prey over the vast territories these animals inhabit. It’s key to communicating with other whales, too.

A CT scan of two halves of a dead whale
Ted Cranford, San Diego State University

Human technology, meanwhile, has made the ocean a noisy place. The propellers and engines of commercial ships create chronic, low-frequency noise that’s within the hearing range of many marine species, including baleen whales like the minke. The oil and gas industry is a major contributor, not only because of offshore drilling, but due to seismic testing for potential drilling sites, which involves blasting air at the ocean floor and measuring the (loud) sound that comes back. Military sonar operations can also have a profound impact; so much so that several years ago, environmental groups filed lawsuits against the U.S. Navy over its sonar testing off the coasts of California and Hawaii. (The environmentalists won, but the new rules may not be much better.)

Using the CT scans and computer modeling, San Diego State University biologist Ted Cranford predicted the ranges of audible sounds for the fin whale and the minke. To do so, he and his team scanned the body of an 11-foot-long minke whale calf (euthanized after being stranded on a Maryland beach in 2012 and preserved) with a CT scanner built to detect flaws in solid-fuel rocket engines. Cranford and his colleague Peter Krysl had previously used the same technique to scan the heads of a Cuvier’s beaked whale and a sperm whale to generate computer simulations of their auditory systems [PDF].

To save time scanning the minke calf, Cranford and the team ended up cutting the whale in half and scanning both parts. Then they digitally reconstructed it for the purposes of the model.

The scans, which assessed tissue density and elasticity, helped them visualize how sound waves vibrate through the skull and soft tissue of a whale’s head. According to models created with that data, minke whales’ hearing is sensitive to a larger range of sound frequencies than previously thought. The whales are sensitive to higher frequencies beyond those of each other’s vocalizations, leading the researchers to believe that they may be trying to hear the higher-frequency sounds of orcas, one of their main predators. (Toothed whales and dolphins communicate at higher frequencies than baleen whales do.)

Knowing the exact frequencies whales can hear is an important part of figuring out just how much human-created noise pollution affects them. By some estimates, according to Cranford, the low-frequency noise underwater created by human activity has doubled every 10 years for the past half-century. "Understanding how various marine vertebrates receive and process low-frequency sound is crucial for assessing the potential impacts" of that noise, he said in a press statement.

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Women Suffer Worse Migraines Than Men. Now Scientists Think They Know Why
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Migraines are one of medicine's most frustrating mysteries, both causes and treatments. Now researchers believe they've solved one part of the puzzle: a protein affected by fluctuating estrogen levels may explain why more women suffer from migraines than men.

Migraines are the third most common illness in the world, affecting more than 1 in 10 people. Some 75 percent of sufferers are women, who also experience them more frequently and more intensely, and don't respond as well to drug treatments as men do.

At this year's Experimental Biology meeting in San Diego, researcher Emily Galloway presented new findings on the connection between the protein NHE1 and the development of migraine headaches. NHE1 regulates the transfer of protons and sodium ions across cell membranes, including the membranes that separate incoming blood flow from the brain.

When NHE1 levels are low or the molecule isn't working as it's supposed to, migraine-level head pain can ensue. And because irregular NHE1 disrupts the flow of protons and sodium ions to the brain, medications like pain killers have trouble crossing the blood-brain barrier as well. This may explain why the condition is so hard to treat.

When the researchers analyzed NHE1 levels in the brains of male and female lab rats, the researchers found them to be four times higher in the males than in the females. Additionally, when estrogen levels were highest in the female specimens, NHE1 levels in the blood vessels of their brains were at their lowest.

Previous research had implicated fluctuating estrogen levels in migraines, but the mechanism behind it has remained elusive. The new finding could change the way migraines are studied and treated in the future, which is especially important considering that most migraine studies have focused on male animal subjects.

"Conducting research on the molecular mechanisms behind migraine is the first step in creating more targeted drugs to treat this condition, for men and women," Galloway said in a press statement. "Knowledge gained from this work could lead to relief for millions of those who suffer from migraines and identify individuals who may have better responses to specific therapies."

The new research is part of a broader effort to build a molecular map of the relationship between sex hormones and NHE1 expression. The next step is testing drugs that regulate these hormones to see how they affect NHE1 levels in the brain.

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