Mild Dehydration Could Mess Up Your Concentration

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iStock

Research has already shown us that enduring a heat wave without air conditioning can impair our mental performance. Now, a new paper reported by NPR shows that not drinking enough water in the summertime can have a similar impact. According to a meta-analysis published in July in the journal Medicine & Science in Sports & Exercise, even mild dehydration can negatively affect cognition.

Mindy Millard-Stafford, director of the Exercise Physiology Laboratory at Georgia Institute of Technology, looked at 33 studies dealing with dehydration. She found that subjects performed worse in a range of areas—including attention, motor coordination, and goal-oriented thinking—when they were slightly dehydrated compared to when they had consumed enough water that day.

She defined mild dehydration as fluid loss equivalent to about 2 percent of body mass. On a hot summer day, reaching this stage can happen surprisingly fast. If you're hiking in the heat, it might take you an hour to become mildly dehydrated, and if you're going on an intense run, it can take just 30 minutes to sweat out 2 percent of your mass.

That level of dehydration isn't too noticeable (you may just start to feel thirsty), but if you have to do something that requires your full attention, it makes a big difference. In one study published last year, female subjects who were 1 percent dehydrated made 12 percent more errors while playing a game that required them to think quickly. (That paper was funded by PepsiCo, which sells bottled-water brands like Aquafina and Propel, but the researchers designed the study independently, according to NPR.)

Luckily, the brain fog that comes with dehydration has a simple antidote: a glass of water. The biggest roadblock keeping you from staying hydrated may be your inability to recognize dehydration in the first place. To see if you're getting enough water, use this easy skin test throughout the day.

[h/t NPR]

One Good Reason Not to Hold in a Fart: It Could Leak Out of Your Mouth

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iStock/grinvalds

The next time you hold in a fart for fear of being heard by polite company, just remember this: It could leak out of your mouth instead of your butt. Writing on The Conversation, University of Newcastle nutrition and dietetics professor Clare Collins explains that pent-up gas can pass through your gut wall and get reabsorbed into your circulation. It's then released when you exhale, whether you like it or not.

“Holding on too long means the build up of intestinal gas will eventually escape via an uncontrollable fart,” Collins writes. In this case, the fart comes out of the wrong end. Talk about potty mouth.

A few brave scientists have investigated the phenomenon of flatulence. In one study, 10 healthy volunteers were fed half a can of baked beans in addition to their regular diets and given a rectal catheter to measure their farts over a 24-hour period. Although it was a small sample, the results were still telling. Men and women let loose the same amount of gas, and the average number of “flatus episodes” (a single fart, or series of farts) during that period was eight. Another study of 10 people found that high-fiber diets led to fewer but bigger farts, and a third study found that gases containing sulphur are the culprit of the world’s stinkiest farts. Two judges were tapped to rate the odor intensity of each toot, and we can only hope that they made it out alive.

Scientific literature also seems to support Collins’s advice to “let it go.” A 2010 paper on “Methane and the gastrointestinal tract” says methane, hydrogen sulfide, and other gases that are produced in the intestinal tract are mostly eliminated from the body via the anus or “expelled from the lungs.” Holding it in can lead to belching, flatulence, bloating, and pain. And in some severe cases, pouches can form along the wall of the colon and get infected, causing diverticulitis.

So go ahead and let it rip, just like nature intended—but maybe try to find an empty room first.

[h/t CBS Philadelphia]

A Chemical in Spider Venom Could Be a Key to Killing Skin Cancer Cells

Alan Couch, Flickr // CC BY 2.0
Alan Couch, Flickr // CC BY 2.0

Despite their formidable reputation in the eyes of arachnophobes, spiders contribute to human society in a number of positive ways. On a practical level, they can reduce the population of insects in your home by trapping them for meals. Outdoors, they keep pests from destroying gardens and crops, making sure we don't slip into a period of famine and anarchy. In the lab, scientists have identified a number of chemicals in their venom as possible building blocks for medicines treating everything from pain to muscular dystrophy.

That field of study has led to a promising discovery. In Australia, researchers have isolated one particular compound in a funnel-web spider's venom that can diminish skin cancer cells.

Scientists at QIMR Berghofer and the University of Queensland began studying the Australian funnel-web spider known as Hadronyche infensa after a similar Brazilian arachnid, Acanthoscurria gomesiana, was shown to carry a peptide in its venom called gomesin that has cancer-fighting properties. Identifying a similar peptide in the Australian spider, the researchers demonstrated that the chemical was effective in killing skin cancer cells while leaving healthy skin cells alone.

The peptide was tested on human melanoma cells, eradicating the majority of them. In mice, it also slowed the growth of the melanomas. The peptide was even effective in killing cells found in facial tumors of Tasmanian devils, a marsupial susceptible to an aggressive form of skin cancer transmittable through biting. The results were published in the journal Scientific Reports.

These peptides are able to be manipulated, taking on different properties as scientists alter amino acids to create new and potentially more potent versions. It’s hoped that this line of research will lead to the development of treatments for skin cancer in humans.

It's something to think about the next time you consider swatting a spider—though if you happen to reside in Australia and see the funnel-web variety, you might not have a choice. While there are 35 different species of funnel-webs of varying potency, some are so formidable that their fangs can pierce fingernails, and their venom is able to kill a human in less than 15 minutes.

[h/t New Atlas]

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