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  • {♫Intro♫}

  • Negotiating thermostat settings

  • can be one of the most frustrating squabbles

  • you'll ever have.

  • Whether it's family or roommates,

  • or co-workers or classmates,

  • finding that Goldilocks temperature

  • that will suit everyone can be rough.

  • You'd think it would be easier

  • for us all to agree on a comfortable temperature.

  • I mean, we're all human.

  • But there's actually a lot of biology

  • and psychology explaining why different people

  • experience ambient temperatures differently.

  • It all starts with your skin, which is covered

  • in sensory nerves called thermoreceptors that

  • send impulses to your brain,

  • keeping it up-to-date on the temperature.

  • Your brain uses this information to keep your

  • body temperature stable and influence your

  • behavior so can you be comfortable as possible

  • like putting on a hoodie in a chilly room,

  • or peeling off your winter coat on the first day of spring.

  • People generally feel most comfortable somewhere

  • in between the point where they start shivering

  • and the temperature when they start sweating.

  • In both of those instances,

  • the body has to do something to stay comfortable.

  • But within that range, there's what scientists call the

  • thermalneutral zone, or TNZ.

  • That's the range of ambient temperatures where you can regulate your body temperature

  • through dry heat loss alone.

  • That essentially means you can stay comfy just by losing heat to your environmentlike,

  • the heat that radiates from your skin.

  • Some studies investigating the human TNZ place it somewhere between 28

  • and 32 degrees Celcius, but it varies a lot

  • from person to person and place to place.

  • And there are a lot of reasons for that variation.

  • Like, if that range seemed hot to you, that's because it's for naked people.

  • And your TNZ is affected by the clothing you wear because that changes the amount of insulation

  • you have.It's affected by the clothing you wear, for example, because that changes the

  • amount of insulation you have.

  • But there are features inherent to your body that affect it, too.

  • Like, your metabolismthe cellular activity that keeps you alive.

  • People with higher metabolisms produce more heat.

  • So, all other things being equal, they'd have lower TNZs.

  • Of course, all other things are never equal.

  • Like, since fat is great insulator, people who have thicker layers of subcutaneous fat

  • are more likely to have a lower TNZ.

  • Body shape also plays a roletheoretically, since a lot of heat loss occurs via your skin,

  • the more skin you have, the more heat you can lose.

  • But, the more tissue you have overall, the more heat you produce in the first place.

  • So researchers generally talk about body surface area to mass ratios.

  • The larger the ratio, the harder it is to maintain heat.

  • And this may partly explain why women tend to feel colder than men at lower ambient temperatures.

  • There are always exceptions to this, but on average, men tend to be larger than womenthey're

  • typically taller, wider, and heavier.

  • That means they have more skin, but also more tissue overall, so their surface area to mass

  • ratios tend to be smaller than those of women.

  • That could shift their TNZs downwards.

  • And since women have larger surface area to mass ratios on average, they probably don't

  • retain heat as well, so their TNZs are shifted upwards.

  • But let's remember, this isn't just a gender thing.

  • This is a body size and shape thing.

  • Like, there's no way Hafþór Björnsson, Kit Harrington, and Peter Dinklage all have

  • the same thermalneutral zone.

  • Body shape and composition can also help explain age differences in TNZ.

  • Newborn babies are essentially adorable bags of fat, which you might think would keep them

  • warm.

  • But all the fat in those chunky wittle thigh rolls is simply not enough to compensate for

  • the heat they are losing through their skin.

  • The surface area to mass ratios of infants are, on average, twice those of adults.

  • And accordingly, their TNZs are much higher, just like on the other end of the age spectrum.

  • In the elderly, the thermalneutral zone seems to be higher and narrower.

  • That's partly because people tend to lose some of their heat-generating muscles and

  • insulating fat as they age.

  • Some scientists believe the elderly also have a harder time regulating temperature in general,

  • thanks to age-related changes in their blood vessels.

  • And really, there's all kinds of stuff going on in our bodies and brains that can impact

  • how we perceive our environment.

  • Like, having low thyroid hormone levels, or hypothyroidism, can lead to an increased sensitivity

  • to cooler temperatures.

  • The condition slows your metabolism down, so you produce less body heatand that can

  • leave you feeling really cold even though everyone else around you is cozy as can be.

  • And then there's Raynaud's Phenomenon, a condition that causes blood vessels in the

  • fingers and toes to constrict when a person gets cold or stressed out.

  • When this happens, warm blood can't get to the skin as well, so a person's digits

  • feel especially cold.

  • If you feel cold all the time and you're concerned about it, you should definitely

  • talk to a trusted healthcare professional.

  • It never hurts to get things checked out.

  • But the good news is nobody can catchfeeling coldfrom you.

  • Or... can they?

  • There is actually a real phenomenon known as Temperature Contagion, where just looking

  • at someone who appears cold or hot can make you feel colder or hotter, too!

  • For example,in a 2014 study, when healthy volunteers watched videos of people putting

  • their hands in visibly cold water, their hand temperatures actually decreased.

  • And remember, your sensing of the ambient temperature around you starts in your skinso

  • if your skin temperature changes, so does your evaluation of your environment.

  • So whether it's a trick of the mind, the result of a medical condition, or simply the

  • sum of body shape and composition, different people experience a room's temperature differently.

  • Now, this might not seem like a big dealbut it can be, because being outside your TNZ

  • messes with your head a little.

  • For example, a 2019 study actually found that women scored significantly better on verbal

  • and math tests in environments that were just a few degrees warmer than the standard settings

  • for air-conditioning.

  • And the shift didn't significantly harm the men's scores.

  • That's likely because feeling cold impedes some cognitive processesbasically, you

  • can't think as clearly if your body has to devote a lot of energy to keeping you warm.

  • So it might be worth considering upping the thermostat a few degrees if it means the overall

  • performance of the office will improve.

  • Of course, the thermostat wars probably won't be ended so easily, since there are just so

  • many factors that affect how different people feel at a given temperature.

  • But hey, it's a start.

  • Thanks for watching this episode of SciShow!

  • And a special thanks to all of you who support what we do, including our channel members

  • and Patreon patrons.

  • If you want to learn more about how humans regulate temperature, you might

  • like our episode on why body-temperature air feels hot.

  • {♫Outro♫}

{♫Intro♫}

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人々がいつもサーモスタットの上で争っている理由 (Why People are Always Fighting Over the Thermostat)

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    林宜悉 に公開 2021 年 01 月 14 日
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