Meet the inspiring granny who has raced thousands of miles around the world

I was just over halfway through the Marathon des Sables: a six-day, 156-mile race across the Sahara Desert, where temperatures often reach a ferocious 50C.

I’d come down with a stomach bug and was severely dehydrated. 

Every muscle in my body was screaming for me to stop and I didn’t know how to find the strength to carry on.

But despite how awful I felt I was determined to finish the race and kept putting one foot in front of the other.

The funny thing is, I hadn’t always been a keen runner.

In fact I’d only started running regularly three years earlier in my mid-30s.

For many years I had a difficult relationship with my body, having developed anorexia as a teenager.

I began skipping meals when I was 15 but the more weight I lost, the more I wanted to lose.

My teachers realised something was wrong and one day I was called into the headmistress’s office and told that if I didn’t start to eat I’d have to leave the school. 

I agreed to start eating and got back to a healthier weight but deep down I still saw food as my enemy.

After leaving school I married Tim and we had three children: Emma, now 31, Ruaraidh, 30, and Harri, 24.

During my pregnancies I ate well but after my children were born I started starving myself again.

Then when I was 29 I decided that things had to change.

I’d had enough of food dominating my every thought and I didn’t want my children to grow up thinking it was normal not to eat.

I went to St George’s Hospital, London, as an outpatient and the doctor put me on a strict eating plan but I struggled to consume the 3,000 calories a day that was recommended. 

Then after a few months I saw a hypnotherapist who trained me to see food as fuel. It was a long process although after a year of hypnotherapy sessions I began to recover.

However, although my feelings towards food were improving there were still parts of my body I wanted to change.

Then when I was 36 a friend suggested running as a way of toning up.

At that point I could barely run half a mile but I decided to give it a go.

I started on a treadmill at my local gym and although I was horribly unfit I persevered.

I met two mums at the gym who invited me to join them on their 10-mile runs in the countryside.

As we jogged along the track I was amazed by how much I enjoyed myself. 

When we were halfway through we stopped for a snack and I hungrily ate a banana to keep my energy levels up.

For most people eating a banana is no big deal but as a recovering anorexic it felt like a triumph.

Over the next few months I went running at every opportunity and even entered a half marathon.

As I crossed the finish line with my husband and children cheering me on I felt an overwhelming sense of pride and was eager to sign up for another race.

Then one day in 2001, I was in the gym when my friend came bounding over with an excited look in her eyes.

She was holding a page from a running magazine about the Marathon des Sables.

“I’ve found your next race,” she said.

“We have to do it.”

I laughed and was about to tell her it was a ridiculous idea but as I skimmed the page I started to think about what an amazing adventure it would be.

I’d barely travelled since Tim and I got married and it seemed like a great opportunity.

“All right, I’ll do it,” I grinned and entered the race along with two friends.

I was expecting Tim to tell me I was out of my mind but he happily supported me. 

The most difficult part of the epic endurance race would be the fourth day when we had to run 54 miles, more than two marathons, in one day.

What’s more, we would need to carry all the food and medical equipment we needed for the race in backpacks while running in the blistering sun.

Each weekend my two friends and I went on longer and longer runs, slowly increasing the weight in our rucksacks.

As our strength improved I started to believe we really could do it.

When we arrived in the Sahara it was even harder than I’d imagined, with the sweltering heat made worse by the backpacks.

On top of this I got a tummy bug and couldn’t keep any food down.

On the third day I was so dehydrated I had to have five bags of fluid on an IV drip that I carried with me as I ran.

When I woke up on the morning of the fourth day, with the 54-mile slog ahead of me, I started to wonder if I was going to make it.

What had I been thinking, taking on this crazy race? But the thought of coming home having failed kept me going.

With the support of my friends I soldiered on until I crossed the finish line on the sixth day.

I came back to England exhausted and aching but a different woman inside.

My once-feeble body had carried me across the finish line and I started to truly appreciate it.

The high of completing the race made me eager to take on another challenge.

Over the next few years I came third in a 100-mile race across the Himalayas and ran 135 miles through Death Valley in Nevada, USA.

My success in those competitions spurred me on to compete in the 6633 Arctic Ultra, a 352-mile race across the Arctic in just eight days, which I won.

My body got stronger and more athletic, a world away from the weak limbs of someone who had starved themselves for years.

Suddenly I was proud of my body rather than ashamed.

I began attempting world records and I became the fastest woman to run from Land’s End to John O’Groats and the fastest person to cross Ireland on foot.

And although I’m 55 now there’s no chance of me slowing down.

Next month I’m attempting a world record run from Los Angeles to New York in 53 days and hopefully I’ll do more in the future.

Running has shown me how incredible my body is and now I wouldn’t trade it for the world.

To order a copy of Beyond Impossible by Mimi Anderson (£9.99, Summersdale) call the Express Bookshop on 01872 562 310 or visit expressbookshop.co.uk