When Sean Burgess set himself the challenge of running and walking hundreds of kilometres across the UAE in a week, he knew it would put huge strain on his body. But his 619km trek from one end of the country to the other was tougher than perhaps he could have imagined, as despondency, vomiting and pain in his shins, among much else, slowed his progress. The full physical toll of the record-breaking journey has been revealed in a fascinating scientific study published this month that identified biochemical signs of cell damage, inflammation and stress, and found that Mr Burgess lost a large amount of body fat in only a few days. Co-written by a doctor who offered vital encouragement at one of the most difficult points of the challenge, the study has been released before another, perhaps even more demanding event that Mr Burgess will put himself through: rowing 1 million metres on a machine. “I think I was possibly a little bit naive in how brutal it was going to be on my body,” Mr Burgess, 35, said of his record-breaking trip. While Mr Burgess, a Dubai resident from the UK, had previously completed three marathon distances in 24 hours, what was toughest about his mammoth trip across the country in March last year was that he had to do huge distances day after day, with little rest and hardly any sleep. “That’s what I didn’t plan for,” he said. “I slept maybe two-and-a-half hours in the first three days [that was] quality sleep. My body didn’t have the time and energy to repair itself.” The walk and run, split into 15 shifts that averaged about eight hours, began in the far west of Abu Dhabi and ended on the beach in Fujairah. The study in the <i>Journal of Sports Science and Medicine</i> about the extraordinary feat is based on blood tests taken before and after the event, on data recorded by a smartwatch worn during the trip, and on pre and post-event interviews. In the first few days, Mr Burgess suffered diarrhoea, vomiting and muscle cramps and later had water retention in his legs. This fluid retention meant his weight was unchanged by the walk and run, even though the quantity of fat in his body plummeted 45 per cent, from 16.7kg to 9.1kg. Changes in Mr Burgess’s blood indicated stress, cell damage and inflammation. There was a 30-fold increase in the amount of C-reactive protein, a substance produced by the liver in response to inflammation. High levels can indicate damage to cells. Mr Burgess was mildly anaemic after achieving a Guinness World Record by running and walking 619.01km in six days, 21 hours and 47 minutes, the fastest crossing of the seven emirates on foot. The event raised funds for underprivileged children in Uganda. Dr Thomas Boillat, an assistant professor at Mohammed Bin Rashid University Of Medicine and Health Sciences in Dubai, said Mr Burgess was “extremely good at listening to his body” during the challenge. “He knew when to stop,” Dr Boillat said. “He had an amazing mental [attitude]. It’s something that’s just crazy because he must have suffered a lot.” Helping Mr Burgess before, during and after the trip was another of the study’s authors, Dr Alan Kourie, head of the Sports Medicine & Rehab Department at Mediclinic Parkview Hospital in Dubai. He said the walk and run created “huge stresses” that affected the blood, the musculoskeletal, gastrointestinal and immune system. Dr Kourie, who has himself competed in endurance events, saw Mr Burgess when he was three days into his journey and noticed he “was looking gaunt, tired and drained”. “I thought, wow, you’ve still three days to go and however many kilometres ahead and I thought if that was me, I’d be deep in the dark zone there,” Dr Kourie said. “When you’ve been an athlete and done some endurance events, you learn that your body lets you down and it’s going to break but it’s your mind that carries you through most of the time.” So while physical preparation is essential, Dr Kourie said it was also important to prepare mentally and to know “how dark those places are that you go to”. “Which is the interesting thing, because you almost know that they’re going to come,” he said. “So you’re either fearful of them and then you just never do the thing again, or you embrace that fear. “I think that’s where the greatest success lies — actually in coming out of these things on the other side as a stronger version of yourself, which I think definitely happened for him.” Mr Burgess said Dr Kourie’s reassurances on day three that his body, while it would not improve, would not deteriorate further, helped him to remain positive. He had worried that “my body would give up on me”. He said his recovery after the challenge was fairly rapid and, after experiencing, among other things, a painful condition known as shin splints, he was walking normally again about a week later. But his sleeping patterns took longer to return to normal. For the first month he would sleep only an hour or two each night and would wake up with nightmares about having much of the trip left to complete, and it was another month or so before this returned to normal. In April, Mr Burgess was back in record-breaking mode when he rowed for 50 hours and 17 minutes, the longest continuous row for anyone in the 30 to 39 age group. He travelled the equivalent of 421,954 metres on a rowing machine at The Physical Training Company in Al Quoz. Now, he is gearing up for an even bigger challenge: in November he aims to row for one million metres, which is likely to involve about 22 hours of rowing a day for five days. Mr Burgess, who used to work in the technology sector but now runs an adventure company, said he was unsure why he had a “burning desire” to put himself through such hardships. “I’m built a little bit differently,” he said. “I haven’t figured out what’s wrong with me, beyond that it’s in me to try these things.”