Livin' on the MDedge

James Bond taken down by an epidemiologist


Breaking down the hot flash

Do you ever wonder why we scramble for cold things when we’re feeling nauseous? Whether it’s the cool air that needs to hit your face in the car or a cold, damp towel on the back of your neck, scientists think it could possibly be an evolutionary mechanism at the cellular level.

Dog looks out car window Piqsels

Motion sickness it’s actually a battle of body temperature, according to an article from LiveScience. Capillaries in the skin dilate, allowing for more blood flow near the skin’s surface and causing core temperature to fall. Once body temperature drops, the hypothalamus, which regulates temperature, tries to do its job by raising body temperature. Thus the hot flash!

The cold compress and cool air help fight the battle by counteracting the hypothalamus, but why the drop in body temperature to begin with?

There are a few theories. Dr. Robert Glatter, an emergency physician at Lenox Hill Hospital in New York, told LiveScience that the lack of oxygen needed in body tissue to survive at lower temperatures could be making it difficult to get oxygen to the body when a person is ill, and is “more likely an adaptive response influenced by poorly understood mechanisms at the cellular level.”

Another theory is that the nausea and body temperature shift is the body’s natural response to help people vomit.

Then there’s the theory of “defensive hypothermia,” which suggests that cold sweats are a possible mechanism to conserve energy so the body can fight off an intruder, which was supported by a 2014 study and a 2016 review.

It’s another one of the body’s many survival tricks.

Teachers were right: Pupils can do the math

Teachers liked to preach that we wouldn’t have calculators with us all the time, but that wound up not being true. Our phones have calculators at the press of a button. But maybe even calculators aren’t always needed because our pupils do more math than you think.

Close-up of eyes pxfuel

The pupil light reflex – constrict in light and dilate in darkness – is well known, but recent work shows that pupil size is also regulated by cognitive and perceptual factors. By presenting subjects with images of various numbers of dots and measuring pupil size, the investigators were able to show “that numerical information is intrinsically related to perception,” lead author Dr. Elisa Castaldi of Florence University noted in a written statement.

The researchers found that pupils are responsible for important survival techniques. Coauthor David Burr of the University of Sydney and the University of Florence gave an evolutionary perspective: “When we look around, we spontaneously perceive the form, size, movement and colour of a scene. Equally spontaneously, we perceive the number of items before us. This ability, shared with most other animals, is an evolutionary fundamental: It reveals immediately important quantities, such as how many apples there are on the tree, or how many enemies are attacking.”

Useful information, indeed, but our pupils seem to be more interested in the quantity of beers in the refrigerator.


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