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

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.