How Far Can You Run?


Dean Karnazes on a typically epic training run

What is Dean Karnazes made of? When the US ultra-marathoner announced his plan to run 50 marathons through 50 American states in 50 days, people thought he was either superhuman or insane. Mainly the latter. "Mad... 50 marathons??!! He must be..." said RW member Dark Vader of Karnazes, in the title of his forum thread. "Mad," agreed Brizo. And when we rang sports physician Dr Patrick Milroy, his first comment was: "Mad."

But just as Karnazes was announcing his own plans, his fellow American Sam Thompson was reaching the end of his own feat of endurance – running 51 marathons in 50 days. So maybe it's not such a rare (or crazy) talent, after all? Forty-three-year-old Karnazes, who embarks on the North Face Endurance 50 on September 17, is first to admit that he's not unusual. "I really don't consider myself to be gifted in any sort of way," he says. "I just really love to run." He claims that, with
a reasonable level of fitness and the right mental attitude, we’d all be surprised by how far we can run.

Patrick Milroy agrees that mental attitude is the key to making the leap from the odd half-marathon to ultra long-distance running. "Someone who runs 50 marathons in 50 days is not superhuman physically, but he does have a very unusually strong attitude," he says. "The big factor stopping most of us going out and running a marathon day after day would be thinking: Oh, do I have to do this again? Most of us simply would not be able to face it psychologically."

"The mind can be extraordinarily powerful," says sports psychologist Dr Jill Owen. "With the right mindset, most runners can far exceed their expectations. When you're 'psyched up' your levels of adrenaline increase, making your body ready for action. It's the fight or flight response – your tolerance for pain, physical strength and stamina all improve. When you’re in this mindset, the average runner can be capable of major achievements."

Each to her own So how "major" can these achievements be, exactly? Assuming your mind is in it, and you’re marathon-fit, can you psych yourself to run 50 miles, 100 miles... or 50 marathons in 50 days?

The answer is a little disappointing. "It varies from person to person," says chartered physiologist Sammy Margo. "There’s no defined limit to what the average person, or marathon-fit athlete, can run. It’s just not possible to say ‘this is the number of miles a human being can run until they crash, or break their bones’.

"We know that it’s astounding what the body can tolerate, but the actual ceiling is very much an individual thing. You can find out a lot about someone’s endurance from a VO2 max test, but there are obvious limitations: first, you can’t force someone to run on a treadmill until they literally break down, and also it’s not usually reaching your cardiovascular limit that makes you have to stop running after a certain distance."

The thing that makes fit long-distance runners stop, says Sammy, is pain and discomfort. "You might never have run more than 10K because you get terrible knee pain. It’s very typical that marathon runners have the cardiovascular fitness to run further, but it’s the pain that stops them."

Body type and genetics are another – frequently controversial – factor in determining how far you can run. "It’s no coincidence that very successful long-distance runners are often Kenyan, with huge natural lung capacity and slender bodies," says Sammy Margo. "It’s not racist to say that, it’s just an example of how your natural build can make a difference to your endurance."

How to find your limit The good news is that even if genetics aren’t on your side, there are ways to extend your individual threshold. "The main factor is consistent training," says Sammy. "There’s lots of research showing that consistency is the main underpinning issue in how far you can run. Quality of training is also a big factor. With the right training, someone in a wheelchair can be trained to stand and to run, and a marathon runner can be trained to do 50 marathons."

Dean Karnazes, who runs up to 150 miles a week in training, and whose "long training runs" have included the Western States 100-miler and the Badwater 135 in Death Valley, certainly seems to have the training under control. His epic preparation will have contributed to physical changes such as strengthening his heart muscles and increasing his cardiac output, and his slow pace – an average 4:45-hour marathon pace during the Endurance 50 – will allow his body to recover as he goes along.

Add the right mental attitude, says Jill Owen, and you have a winning recipe for reaching your full endurance potential. "When you’re trying to find your own ceiling, you need to be able to cope with the frustration involved. If your first attempts at running long distances are over-ambitious, you have to be patient at coping with the setbacks and improving specific areas of your running.

"For example this may involve treatment for injury, or strength work on a particular muscle group. Sometimes people reduce their ceiling by showing extreme dedication in some areas, such as their running training, but neglecting others such as diet.

"Being resilient in the face of disappointment, having the creativity to think of ways of overcoming problems and being prepared to try different options are all qualities that raise a person's potential. Fifty marathons in 50 days would seem like a particularly exceptional achievement, but with the right preparation, patience and attitude, most people can run much further than they’d expect."

But exactly how far, no-one can say.

Don't overdo it

All the experts we spoke to agreed on one thing: "can do" doesn’t necessarily mean "should do". If you’re in pain, that’s your body’s way of telling you to stop and recover. "Ninety-nine point nine per cent of runners would be ill-advised to run 50 marathons in 50 days," says Patrick Milroy. "There are risks of chronic damage to your body by doing this sort of thing. Chronic stress fractures would be the main risk, and damage to your muscles. The body was designed to run long distances, but not to this level day after day."

Jill Owen also advises caution. "Mental strength can help you run through tiredness, which is fantastic. But if you run through a stress fracture, it may be detrimental to your running and your health later on. The mind is incredibly powerful, but use it wisely!"

50 marathons in 50 days: What you said
  • B (Ewok's Mate): "It's like visiting the dentist every day for 3 months just to test the limits of human pain. It wouldn't be laudable, just plain stupid. When I was training for my marathon I got so bored on a Sunday, 3.5 hours running round Deal. That's why I can't really think to myself 'Wow, what an athlete for doing 50 maras in 50 days', instead I think 'What a lemon'. The same reaction I'd experience if someone told me they were decorating 50 bedrooms in 50 days."
  • Too Much Water: "Apparently some crazy Germans do 12 in 12 days for the 12 days of Christmas."
  • Plodding Hippo: "I get bored if long running alone, but in a race I'm in too much physical discomfort to get bored so I play mind games to keep going."
  • fat buddha: "Pah, he ought to try a Decaman - 10 Ironman race distances. Swim 24 miles, bike 1120 miles and run 262 miles (10 maras) - all within 14 days..."