How Does Blood Pressure Work?

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iStock

Your heart is the master pump for all the blood in your body. With every heartbeat, your heart pushes your blood to all the vital parts of your body, such as muscles and bones, through a network of arteries, capillaries, and veins. As blood flows through the tube-like arteries, it presses up against the walls of the blood vessels with varying degrees of strength. The strength or weakness of this pressure is called your blood pressure (BP).

Each time your heart squeezes, moving your blood to its various destinations, your blood pressure goes up—this number is referred to by a blood pressure reading as systolic. Then, as the heart relaxes after each contraction, your blood pressure goes down; that is called the diastolic reading. Together, these two numbers are presented as a score, systolic over diastolic: Your doctor might tell you that your BP is “120 over 80.”

According to the American Heart Association (AHA), normal blood pressure should reflect systolic pressure between 90 and 120, over a diastolic pressure between 60 and 80. Your doctor may take this measurement with a fancy-named instrument called a sphygmomanometer—an inflatable rubber cuff attached to a manual air pump. When the doctor inflates the cuff at your arm with air, it temporarily cuts off blood flow, and when it releases, the blood starts flowing again, revealing those two key numbers.

Nowadays, though, doctors are recommended to use an automatic blood pressure cuff, which relies on a different method and seems to be more accurate. While the manual cuff relies on auscultation, in which the doctor listens for the correct pressures using a stethoscope/microphone, automatic blood pressure cuffs are usually oscillometric. When blood passes under the cuff, the arm increases in circumference ever so slightly. And by measuring the amplitude of the oscillations (hence oscillometric) at a continuous interval of pressures, blood pressure can be calculated in much the same way.

If you have high blood pressure, a.k.a. hypertension—approximately 130/80 or higher in a person of average health—your heart is working too hard to pump the blood through your body, which becomes dangerous. According to the AHA [PDF], elevated blood pressure is 120–129/less than 80; hypertension stage 1 is 130–139 (systolic) or 80–89 (diastolic); and hypertension stage 2 is 140 or higher (systolic) or 90 or higher (diastolic). If your blood pressure hits 180/120, you're in hypertensive crisis, and you should get help.

If you fall into the above categories, your doctor will recommend changes to diet and exercise and probably medication. High blood pressure is often a precursor to heart disease or a heart attack and can be a side effect of other diseases, such as diabetes. However, your blood pressure can temporarily rise due to stress, pregnancy, and even some common medications, including over-the-counter pain relievers and antidepressants. One high reading will not necessarily mean you have hypertension—but it’s good to keep vigilant.

Editor's note: This story was updated in July 2018 to reflect new blood pressure guidelines from the AHA.

This Cooling Weighted Blanket Helps You Sleep Soundly Without Overheating

Research has shown that weighted blankets, originally made for kids with anxiety and sensory processing issues, may also alleviate stress and anxiety in adults as well. But if you're someone who gets hot easily, sleeping beneath a heavy blanket at night may feel uncomfortable. The Hush Iced, a cooling version of the popular Hush blanket, is designed to change that.

One of the most common complaints Hush Blankets received from customers after releasing its original weighted blanket was that it made users too hot. So the team at Hush tweaked the outer material to make it friendlier to people who are prone to overheating while still providing the soothing deep-touch pressure of a weighted blanket.

The new Hush Iced, currently raising money on Kickstarter, comes with a special ultra-cooling cover. The thin bamboo and cotton fabric wicks away sweat and helps maintain your body temperature through the night. Inside is Hush's classic weighted blanket, with weight distribution technology that helps you feel relaxed and secure in bed. If you already have a Hush weighted blanket at home, the cooling cover is also available separately.

The Hush Iced weigh 15 to 25 pounds, and comes in standard (48-by-78-inch) and queen (60-by-80-inch) sizes. (Generally, Hush recommends choosing the weight of your blanket based on body weight—check out the Hush site for more information on selecting the right one.)

Buy it on Kickstarter starting at $128. The cooling cover is available on its own for $39.

Chronic Pain Happens Differently in Men and Women

iStock.com/PeopleImages
iStock.com/PeopleImages

Women often feel colder than men due to physical differences. Now, a new study shows that the two sexes have different biological processes underlying a specific kind of pain, too. As WIRED reports, research published in the journal Brain revealed that different cells and proteins were activated in men and women with neuropathic pain—a condition that is often chronic, with symptoms including a burning or shooting sensation. While scientists say further research is needed, these findings could potentially change the way we treat conditions involving chronic pain.

A team of Texas-based neurologists and neuroscientists looked for RNA expressions in the sensory neurons of spinal tumors that had been removed from eight women and 18 men. Some of the patients had pain as a result of nerve compression, while others had not experienced any chronic pain. While studying the neurons of women with pain, researchers noticed that protein-like molecules called neuropeptides, which modulate neurons, were highly activated. For the men, immune system cells called macrophages were most active.

"This represents the first direct human evidence that pain seems to be as sex-dependent in its underlying biology in humans as we have been suggesting for a while now, based on experiments in mice," Jeffrey Mogil, a professor of pain studies at Montreal's McGill University, who was not involved in the Brain study, tells WIRED.

So what exactly do these new findings mean for sufferers of chronic pain? Considering that clinical trials and drug manufacturers have traditionally failed to distinguish between the sexes when it comes to developing pain medication, the study could potentially form a foundation for sex-specific pain therapies that could prove more effective. This might be especially promising for women, who are more likely to have some condition that cause persistent pain, such as migraines or fibromyalgia.

"I think that 10 years from now, when I look back at how papers I've published have had an impact, this one will stick out," Dr. Ted Price, a neuroscience professor and one of the paper's authors, said in a statement. "I hope by then that we are designing clinical trials better considering sex as a biological variable, and that we understand how chronic pain is driven differently in men and women."

[h/t WIRED]

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