By Edward Johnson
Director, GIA London

Edward Johnson, director of GIA London, completed the Marathon des Sables - a 140-mile race across the Sahara Desert - in April. Photos courtesy of Edward Johnson

I've been an erratic ultramarathon runner for more than 15 years and decided to attempt MdS as a challenge for my 40th birthday. Sark Kenny, a gemologist and running friend, and I decided to do it together; we sent in our deposit checks in February 2005, thereby committing to two years of mental and physical preparation. I also decided to use the race to raise funds for charity.

Many people told me that my perspective on life would change after MdS; I now completely understand and agree. I experienced exhaustion, elation, humility and grief. But more than anything, I experienced the simple pleasure of being part of a colorful, nomadic family pushing themselves to the limits and moving slowly across one of the world's harshest and most beautiful environments.

The course, which is kept secret each year until two days before the race, covered 140 miles in seven days within Errachidia Province in southeastern Morocco on the border of Algeria. We were required to carry everything we needed to survive, including at least 2,000 calories of food per day. We were given a daily water ration of 9 liters (2.38 gallons), which was typically handed out at 10- to 15-kilometer (6.21- to 9.32-mile) intervals on the course.

I ran a very careful race and found myself getting stronger and faster each day. We began at 9 a.m. and traversed a marked course that was between a half to a double marathon. I eventually finished in the 236th position, clocking in at 35 hours and 17 minutes (the winning time was 17 hours and the slowest more than 70).

It is amazing what the body can do for you if you prepare it well. I only had three small blisters by the end of the race, which was extremely lucky and rare. For many, the event was one of constant pain, mainly due to their feet quickly deteriorating and blistering in the most horrific way. For others, damaged legs and suspicious heart rates brought an untimely end to their adventure.

But few people fail to finish the MdS because of exhaustion. There is no doubt that the mind plays a large part in our ability to complete arduous events of this nature. The concept of "one foot in front of the other" and setting small targets to achieve the ultimate goal are an ultrarunner's mantra. I can still recall the exact moment in my head when I switched from thinking "if" I finish to "when." Though it is called a race, simply finishing is a personal achievement regardless of time and position.

Edward Johnson, director of GIA London, completed the Marathon des Sables - a 140-mile race across the Sahara Desert - in April. Photos courtesy of Edward Johnson

Out of the 757 men and women from 32 countries who started the race, 29 dropped out and one tragically died.

It was the most intense and incredible experience of my life.

Running the MdS taught me that if you set a target for yourself, work hard to achieve it and make the necessary sacrifices, the experience of completion is intoxicating. This applies to whatever your personal challenge might be: running across the Sahara, completing your Graduate Gemologist diploma or getting a dream job in the jewelry industry.

I would like to thank the many members of the jewelry industry for their sponsorship and verbal support. I have raised almost £7,500 (more than $15,000) and counting for Workaid, a UK-based charity that tackles poverty in developing countries by supplying disadvantaged people the tools they need to earn a living, and of this I am most proud.