HOW FAR CAN WE PUSH OUR BOD­IES?

WE HU­MANS are pro­grammed to grow stronger, faster, and smarter; to climb higher, live longer and pop­u­late ev­ery last me­tre of real es­tate. Many world records have been top­pled in the past few decades, but when will our progress peak? No mat­ter how we enha

Reader's Digest Asia Pacific - - Contents - JUDY DUT­TON

Can hu­mans go much fur­ther, phys­i­cally and men­tally, be­fore we reach our lim­its?

Most Weight We Can Lift:

455 kilo­grams

The world’s strong­est weightlifters can hoist 455kg – but Todd Schroeder, a bioki­ne­si­ol­o­gist at the Univer­sity of South­ern Cal­i­for­nia, thinks they’re wimp­ing out. Our brains limit the num­ber of mus­cle fi­bres ac­ti­vated at any time to keep us from get­ting hurt. “Turn that safety off, and you can ­pro­duce a lot more force,” Schroeder says. He thinks op­ti­mal train­ing, ­in­clud­ing men­tal, may help ath­letes tap as much as 20% more strength.

Tallest We Can Grow:

2.72 me­tres

In the 1930s, Robert Per­sh­ing ­Wad­low, aka the Gi­ant of Illi­nois, reached this world record due to an over­ac­tive ­pi­tu­itary gland. His towering stature se­verely stressed his cir­cu­la­tory sys­tem (he couldn’t feel his feet) and placed struc­tural pres­sure on his bones (he wore braces when he walked). As a ­re­sult of th­ese phys­i­cal lim­i­ta­tions, ­engi­neer Thomas Sa­ma­ras es­ti­mates that while the av­er­age hu­man has grown taller due to bet­ter nu­tri­tion, we will even­tu­ally level off at about 2.1m. His stud­ies have also found shorter peo­ple gen­er­ally live longer lives – ­al­though oth­ers dis­pute this claim.

Most We Can Re­mem­ber:

1 mil­lion gi­ga­bytes

If your brain’s one bil­lion stor­age neu­rons held one mem­ory apiece, “you might have only a few gi­ga­bytes of stor­age space, sim­i­lar to a USB flash drive,” says Paul Re­ber, a ­psy­chol­o­gist at North­west­ern Univer­sity. But each neu­ron ac­tu­ally forms about 1000 con­nec­tions to other ­neu­rons, ex­po­nen­tially ex­pand­ing the brain’s stor­age ca­pac­ity to around one mil­lion gi­ga­bytes. The bot­tom line is that stor­age isn’t the prob­lem: our abil­ity to record and re­trieve data is.

Smartest We Can Get:

IQ of 198

This hon­our goes to Ab­des­se­lam ­Jel­loul, who set this record in a 2012 adult IQ test. But a few prodi­gies aside, if your score ap­proaches ­Ein­stein’s 160, you’re prob­a­bly at ­hu­man­ity’s up­per reaches. “Our brain operates close to its in­for­ma­tion-pro­cess­ing ca­pac­ity,” says Si­mon

Laugh­lin, a neu­ro­bi­ol­o­gist at the ­Univer­sity of Cam­bridge. This is due to a range of elec­tri­cal trade-offs: if the hu­man brain were to get big­ger, it would be less ef­fi­cient.

Fastest We Can Run:

10.5 me­tres per sec­ond

Af­ter Olympic sprinter Usain Bolt broke the 100m world record at the 2008 Olympics, Mark Denny, a bi­ol­o­gist at Stan­ford Univer­sity, ­won­dered whether “Light­ning Bolt” had sprinted as fast as a hu­man can go. Af­ter hav­ing graphed 100m records back to the 1920s, Denny pre­dicts ­­hu­mans will plateau at about 9.48 sec­onds over 100m, or 0.10 sec­onds faster than Bolt’s cur­rent record of 9.58 sec­onds (10.44 m/s) – a lot speed­ier in a sport in which dif­fer­ences are mea­sured by 100th of a sec­ond.

Most Friends We Can Have:

150 friends

We’re not talk­ing about Face­book friends, but real ones that you can ­de­pend on. With that cri­te­ria, 150 is the max, says Robin Dun­bar, a ­psy­chol­o­gist at the Univer­sity of ­Ox­ford. This is the num­ber of peo­ple you can have a re­la­tion­ship with ­in­volv­ing trust and obli­ga­tion, he says, not just names and faces. Dun­bar ­ex­am­ined cen­sus data on tribal groups, which av­er­aged out at 148 mem­bers. The same num­ber reg­u­larly crops up in mod­ern busi­ness. Most fa­mously, the founder of GoreTex ­i nsisted on com­pletely sep­a­rate ­fac­tory units of 150 work­ers so peo­ple would be more likely to be pals.

Longest We Can Go With­out Sleep: 11 days

In 1964, Randy Gard­ner, a 17-year-old from San Diego, woke up at 6am to start his school sci­ence project: an at­tempt to break the world record for days with­out sleep. He suc­ceeded. Gard­ner made it to 11 days while Wil­liam De­ment, a Stan­ford Univer­sity ­psy­chi­a­trist, doc­u­mented it and mon­i­tored his vi­tals. Gard­ner ­re­mained lu­cid, al­beit ir­ri­ta­ble. Since then, stud­ies have shown that rats de­prived of shut-eye will die within 30 days, and a rare dis­ease called fa­tal fa­mil­ial ­in­som­nia, which stops peo­ple from doz­ing off at all, causes death in a few months to a few years.

Longest We Can Go With­out Solid Food:

382 days

Of course, this feat is eas­ier to ­ac­com­plish if you’re obese to start with – which was the case with “Pa­tient A.B.” The 27-year-old, un­der ob­ser­va­tion at the Univer­sity of Dundee in Scot­land, weighed 207kg when he started his fast in the 1973 study. With a diet of purely non-caloric food such as yeast and mul­ti­vi­ta­mins, he dropped to 82kg by the time the study ended, more than a year later. Need­less to say: don’t try this at home.

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