I Love Running You Hate it Here's Why

It's the final day of the Marathon des Sables, a six-day, self-supported, 156-mile, multi-marathon run across the Sahara desert. It's above 100 degrees and I've got 3 miles left to go. After five days running up mountainous desert dunes and through dried up rocky river beds, carrying all my own kit, I'm spent.

There's only a short distance to go, but my entire body is screaming “Stop!" What's worse is that my head is eager to listen.

Then something magical happens. I pop in some headphones and get moving. I feel a rush, like heat radiating from the parched desert sand, rise all the way up my spine. Goosebumped hairs stand up on the back of my neck and my legs suddenly feel free. A smile spreads across my face.

I glance down at my watch and realize that in the final few miles of the "world's toughest footrace," I'm running marathon-pace miles. I was almost dead and now I'm moving faster than I have all week through the dust, heat and sand. Despite the ever-present discomfort, I've never been happier in my life—except on my wedding day, of course.

It's these physiological advantages that put running at the heart of human evolution and potentially explain why we're the only species that still voluntarily runs long distances for pleasure — some 65 million Americans last year alone.

If humans are designed to run, why don't I like it?

It's only natural that we prefer things we're better at than things we struggle to do. So, while you may think you dislike running, it could be you just haven't found the distance that suits you best.

Just like some humans are better at creative pursuits while others prefer math, your genetic make-up can influence how far and fast you can run. Case in point: the difference between the bodies of sprinters and marathon runners.

Physics suggests that lighter, smaller frames tend to be better suited for running long distance as they have less weight to carry, while those with larger, more muscular frames have the power needed to explode off the start line in a sprint and the lengthy stride to get them to the finish quickly in short races.

And while it'd be nice to say we can all be good runners with a bit of training, sadly, for one-fifth of the population, while they may be happy with a slow jog round the block, they're never going to complete a speedy marathon.

Scientists from England's Loughborough University found that a person's genes can predict how well their body will respond to the stamina training needed for a marathon and consequently how they'll perform in an endurance race.

“From our work, we know that 20 per cent of people do not respond at all to training and in fact can get worse," Jamie Timmons, who was head of systems biology at Loughborough University when the study was conducted in 2013, told The Telegraph. "They push themselves as hard as everyone else, but their muscles do not extract the same amount of oxygen."

Timmons found that for these people, logging the marathon miles could actually result in a decrease in performance which is likely to make it hard to enjoy long runs and love running.

Do people who love running have a certain mindset?

I know it sounds a bit weird when I tell people about the euphoric love I felt for running during my epic desert ultra — despite the numbing pain in my feet, the sapping lack of energy, the aching muscles and joints that felt like I'd grown a skeleton made of rusty steel. It's as though I have some kind of masochistic love of pain. I don't.

So is a runner's brain wired differently?

When you're running hard in a race or going over a long distance, you're usually pushing yourself to the edge of comfort, so it's not surprising that studies have found that high achieving athletes are mentally tough and ultra-runners feel less pain than non-ultra-runners.

While more research is needed to discover whether some personality types are better at endurance sports than others, it's thought ultra-runners think about pain in a different way, and a degree of mental toughness certainly helps people push themselves. But mental toughness is something you can work on — many elite athletes employ sports psychologists to gain an edge — and you will naturally learn to deal with physical discomfort through training.

That said, why would you run when you could sit on a comfy couch? Lieberman, of Harvard, has found that although we're built to run, and certainly can when we need to, we're also naturally wired to conserve energy. When early humans were not hunting scarce food supplies, conserving energy through rest was essential for survival and procreation. Thus, Lieberman argues, humans evolved to exercise only as much as needed to sustain life. This could be why the first miles of any run tend to feel tough and your mind screams at you to stop.

But run for long enough and you'll realize what it is that keeps many regular runners going back for more: That elusive runner's high — an ecstatic biochemical and neurological cocktail that some describe as a feeling of invincibility with simultaneously reduced discomfort and even the loss of awareness of time. If you've never felt the runner's high, it's no surprise you don't love running.

So what exactly is runner's high?

Evolutionary theory says our bodies are equipped to take the pain out of physical endurance, which, once upon a time, was essential for hunting and not being hunted ourselves. Thus, the runner's high was vital for staying alive. “Endurance running combines every element necessary for the glorious runner's high," says Paul Arciero, an exercise scientist at Skidmore College in Saratoga Springs, New York. Why? “It's rhythmical, it's continuous, it uses your whole body, and it's moderate in intensity. When those four levers are triggered, you elicit natural euphoria and opiate activity in your brain."

For years, it was believed that exercise-triggered endorphin release was solely responsible for this opiate-powered runner's high. But recent research from the University of Heidelberg, in Germany, shows endocannabinoids — a chemical that is released during exercise and triggers pain relief and reduced anxiety akin to cannabis — are one crucial component of what constitutes the runner's high.

Learn to love the struggle

For some, running may just always be a slog. For others, learning to love the sport may be about building physical fitness and fine-tuning their nutrition so that they can run long enough to achieve the runner's high and want to run some more.