Peter Wilkinson proudly wears the medal he received for completing the 2012 Brighton Marathon.

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Peter Wilkinson is CNN's Senior Digital Producer

He is a veteran of the London and Brighton marathons

The marathon covers a distance of 26.2 miles (42km)

London CNN  — 

After three marathons, I really should know what to do by now. There is simply no substitute for plenty of training when running a marathon. But this Sunday I will be pounding the streets of my hometown Brighton, southern England, having done almost no preparation. So how will I fare?

Ideally a marathon runner should be doing 40 to 50 miles a week for at least three or four months before race day. The training is intensely boring, but it conditions every part of the body – including the mind – for the pummeling that 26.2 miles exerts on it. My knees, shins, Achilles and hamstrings hurt the most as the miles mount, and they can only get stronger and more resilient through practice.

I used to dismiss as a myth the notion of the “wall,” the pain barrier that marathon runners experience at about 20 miles. This happens when energy reserves are depleted, forcing the body to start burning fat. It can leave you feeling nauseous – again, training helps to condition the body to running long distances. However, I hit the wall in both my last two races, and I’m terrified it will happen again this Sunday.

Before my previous well-prepared marathons I ran respectable times of about three hours and 30 minutes. This year though, just like the excuses I used to give for failing to do my homework at school, I simply haven’t had time to do enough practice runs.

The only real distances under my belt are the three miles that I walk each day from Victoria Station in London up to CNN’s bureau in Soho. An intense workload at both the office and home mean I rarely have time to spend the one or two hours on top of this that I should be doing.

So in a desperate effort to get race-fit, I have been trying to pack about four months of training into just two or three weeks. But three demanding children and a house restoration project mean the only time I’ve had to run is late at night. This means I’ve been trudging along Brighton’s seafront, running the gauntlet of its colorful nightlife, such as night-clubbers, stag and hen nights and assorted other lost souls.

I’ve heard several other runners recently talking smugly about tapering down in the final stages of marathon preparation. I’m still tapering up. Last night I ran 17 miles and felt shattered. I hope I feel better for this Sunday’s race. I don’t know if I’ll last the distance but I intend to find out. Follow my last-minute preparations here. Next week I’ll tell you how it went.

A week later …

Well, it seems I was fitter than I feared! After worrying that I hadn’t done nearly enough training for Sunday’s Brighton marathon, I finished in a creditable three hours and 35 minutes – only a couple of minutes slower than last year’s time.

Most of my longer runs were done in the fortnight before the race – contradicting the usual advice that you train for three or four months, then ease off, or taper, in the last 10 days or so.

Still, I must have been doing something right, as I felt reasonably comfortable for most of the race. It only really became an ordeal for the last two or three miles, when my legs and feet felt like concrete and my chest started to tighten.

I was helped on my way – as ever during a marathon – by the thousands of spectators lining the route. Many of them handed me jelly baby sweets, which provided a welcome lift as I neared the finish. The weather was perfect for running: sunny but fresh, and I in fact enjoyed, yes enjoyed, the whole day.

I felt pretty rough straight after the race, but better than last year when I was sick after I crossed the line. But I managed to keep walking – always the best strategy, and walked the mile back to my home where I lay on the sofa all afternoon. I managed to hobble about the house, but I got my children to be my slaves for the day.

I didn’t sleep very well on Sunday night because my legs were tingling so much. On Monday I went to work in London and my legs were more stiff but not painful, but I managed to walk three miles. It was a bit of a struggle getting in and out of my chair but by Tuesday the stiffness had pretty much gone, and now I can’t tell I ran 26 miles four days ago. I even ran the 1.5 miles from Victoria Station to the CNN bureau in Soho this morning in 15 minutes.

I can only conclude that the exercise I take during the rest of the year is sufficient to keep me fit enough to run a marathon. Who knows: maybe training is all a myth! It certainly saved me a lot of time – I always find the worst thing about preparing for a marathon is the monotony of running mile after boring mile for months beforehand

So I would implore anyone considering a marathon to get out and give it a go: it’s really not as hard as you might think. Sure, 26.2 miles (42 kilometers) is a long way, but as long as you have a decent level of fitness, you’ll be able to run a fairly fast marathon. You never know, you might even enjoy it!