What happens to your body at the top of Mount Everest - Andrew Lovering

Prevoditelj: Katja Martinovic Recezent: Petra Lauš

If someone teleported from sea level to the top of Mt. Everest,

Kad bi se osoba teleportirala s razine mora na vrh planine Everesta

things would go bad fast.

stvari bi brzo krenule nizbrdo.

At an altitude of 8,848 meters,

Pri nadmorskoj visini od 8,848 metara,

barometric pressure is approximately 33% of what it is at sea level.

pritisak je oko 33% pritiska na razini mora.

This means there's significantly less oxygen in the air,

To znači da ima značajno manje kisika u zraku

and our teleported individual would likely suffocate in minutes.

te bi se naša osoba najvjerojatnije ugušila unutar par minuta.

However, for people that make this same journey over the course of a month,

Međutim, kod ljudi koji isti put penju mjesec dana,

it's possible to survive at the peak for hours.

postoji mogućnost da na vrhu prežive nekoliko sati.

So what can happen to our bodies in just one month

Što se to dogodi s našim tijelima u samo jedan mjesec,

that allows us to endure this incredible altitude?

što nam omogućuje da izdržimo na tako velikoj nadmorskoj visini?

Let’s imagine you’re one of the 5.8 billion people

Zamislimo da ste jedna osoba od 5,8 milijardi ljudi

living less than 500 meters above sea level.

koji živi manje od 500 metara iznad razine mora.

When you take a breath at this altitude,

Kada udahnete na toj nadmorskoj razini,

your lungs fill up with air composed of numerous gases and compounds.

vaša pluća napune se zrakom koji sadrži brojne plinove i spojeve.

Most important among these are oxygen molecules,

Najvažnije među njima su molekule kisika,

which bind to the hemoglobin in your red blood cells.

koje se vežu za hemoglobin u vašim crvenim krvnim stanicama.

Blood then circulates throughout your body,

Tada krv cirkulira kroz vaše tijelo

bringing essential oxygen to all your cells.

donoseći potreban kisik svim vašim stanicama.

But as altitude increases, the air starts to get thinner.

Međutim, s porastom nadmorske visine, zrak postaje rjeđi.

The relative amounts of each compound remain the same

Relativna količina svakog spoja ostaje ista

well into the upper atmosphere,

dizanjem u gornju atmosferu,

but overall, there is less oxygen for our bodies to absorb.

ali svejedno je kisika koji tijelo apsorbira sve manje.

And if you ascend to altitudes above 2,500 meters,

Ako se uspnete na nadmorsku visinu iznad 2500 metara,

the resulting oxygen deprivation can cause a form of altitude sickness

deprivacija kisikom može uzrokovati tip visinske bolesti,

known as AMS,

poznatiji kao akutna visinska bolest,

often causing headaches, fatigue and nausea.

koji često uzrokuje glavobolje, umor te mučninu.

Fortunately, AMS only happens when we ascend too fast,

Na sreću, do te bolesti dolazi samo kada se uspnemo prebrzo,

because our bodies have numerous ways of adapting to high altitudes.

zato što naša tijela koriste brojne načine za adaptaciju na velike nadmorske visine.

Within minutes or even seconds of reaching altitudes of 1,500 meters,

Za nekoliko minuta ili čak sekundi nakon uspona na visinu od 1500 metara,

carotid chemoreceptors in your neck sense your blood’s low oxygen pressure.

karotidni kemoreceptori u vašem vratu registriraju nisku razinu kisika u krvi.

This triggers a response that increases the rate and depth of your breathing

To izaziva reakciju koja ubrzava brzinu te povećava dubinu vašeg disanja

to counteract the lack of oxygen.

kako bi se kompenzirao manjak kisika.

Your heart rate also increases

Vaši otkucaji srca također se ubrzavaju

and your heart contracts more tightly to pump additional blood with each beat,

te se vaše srce jače kontrahira i pumpa dodatnu krv svakim otkucajem,

quickly moving oxygenated blood around your body.

čime krv puna kisika kola vašim tijelom.

All these changes happen relatively fast, and if you were to keep ascending,

Sve te promjene relativno su brze te bi se, ako bi se nastavili penjati,

your heart rate and breathing would speed up accordingly.

ubrzali vaši otkucaji i disanje.

But if you stayed at this altitude for several weeks,

Međutim, ako biste ostali na toj visini nekoliko tjedana,

you could reap the benefits of some longer-term adaptations.

mogli biste osjetiti pozitivne strane dugoročne prilagodbe.

Within the first few days above 1,500 meters,

Unutar prvih par dana iznad 1500 metara,

the volume of plasma in your blood decreases,

volumen plazme u vašoj krvi se smanjuje,

which increases the concentration of hemoglobin.

što povećava koncentraciju hemoglobina.

Over the next two weeks, your hemoglobin levels will continue to rise,

Tijekom sljedećih dva tjedna, vaše razine hemoglobina nastavit će rasti,

allowing your blood to carry even more oxygen per milliliter.

što će omogućiti vašoj krvi da nosi još više kisika po mililitri.

Paired with your high heart rate,

Zajedno s visokim otkucajima srca,

this new hemoglobin-rich blood efficiently distributes oxygen throughout your body.

nova krv obogaćena hemoglobinom učinkovito nosi kisik kroz tijelo.

So much so that the volume of blood being pumped with each heartbeat

I to tako učinkovito da se krvni volumen koji se pumpa svakim otkucajem

can return to normal levels.

može vratiti na normalne razine.

Over this same time, your breathing also increases even further

Istovremeno, vaše disanje također se još više ubrzava,

in a process called ventilatory acclimatization.

što se naziva prilagodba disanja.

After this several weeks of extended acclimatization,

Nakon tih nekoliko tjedana produžene prilagodbe,

your body has made enough significant changes to climb even higher.

promjene u vašem tijelu postale su dovoljne da se popnete još više.

However, you’ll still have to spend additional time acclimating along the way,

Međutim, ipak ćete se morati dodatno prilagođavati putem,

often climbing back down to recover before ascending even higher.

često se i spustiti niže i oporaviti prije nego se popnete još više.

Because the summit of Everest isn't just high,

Zato što vrh Everest nije samo visok,

it’s the highest place on Earth.

već je najviše mjesto na svijetu.

And at altitudes above 3,500 meters, our bodies are under incredible stress.

Na nadmorskoj visini iznad 3500 metara, naša tijela su pod nevjerojatnim stresom.

Arteries and veins in the brain dilate to speed up blood flow,

Arterije i vene u mozgu šire se kako bi ubrzale cirkulaciju.

But our smallest blood vessels, called capillaries,

Međutim, naše najmanje krvne žile, kapilare,

remain the same size.

ostaju iste veličine.

This increased pressure can cause blood vessels to leak,

Povećanje tlaka može uzrokovati curenje iz krvnih žila

and fluid to build up in the brain.

te nakupljanje tekućine u mozgu.

A similar issue can occur in the lungs,

Do sličnog problema može doći i u plućima,

where low oxygen causes blood vessels to constrict,

gdje niska razina kisika uzrokuje suženje krvnih žila,

leading to more leaking vessels and fluid buildup.

te posljedično još više žila iz kojih curi i nakupljanje tekućine.

These two conditions— known as HACE and HAPE, respectively—

Ova dva stanja, poznatija kao akutni visinski edemi mozga i pluća,

are incredibly rare,

vrlo su rijetka,

but can be life-threatening if not dealt with quickly.

ali mogu biti opasna po život ako ih se brzo ne riješi.

Some Tibetans and South Americans with family histories

Neki Tibetanci i Južnoamerikanci čije obitelji dugo žive

of living at high altitude

na velikim nadmorskim visinama

have genetic advantages that can prevent minor altitude sickness,

posjeduju genetske predispozicije koje mogu spriječiti slabije visinske bolesti

but even they aren’t immune to these severe conditions.

ali čak ni oni nisu imuni na ova ozbiljna stanja.

Yet despite these risks, climbers over the last century

Ipak, bez obzira na rizike, penjači su tijekom zadnjeg stoljeća

have proved people can go higher than scientists ever thought possible.

dokazali da mogu ići više nego su znanstvenici mislili da je moguće.

Pushing past their body’s limitations,

Bez obzira na tjelesna ograničenja,

these climbers have redefined what humanity can adapt to.

ti penjači redefinirali su granice ljudske prilagodbe.