You're the first person to swim the length of Great Britain. What was it about the idea that you found so alluring?
I was just looking for a challenge. I liked the idea of doing a swim as it would be difficult for me – I'm not a naturally strong swimmer. I thought maybe I could become the fastest person to do it, but after research I found out that no one had even tried it, and there was nothing suggesting that it wasn't possible. I then told people about the idea, and they said I would die trying. I'm really stubborn, so my next thought was to prove them wrong. Before taking on the swim challenge, the furthest you had swum was three miles in a pool – did you wish you had done more?
One of my main regrets was not doing more training. My lack of preparation was down to not having enough time: I spent weeks just trying to organise the route, crew, boats, and food. Money was also an issue – I had to move back in with my mum in Cheltenham, so I didn't live anywhere near the sea, nor could I afford to drive down to Devon to do coastal swims.
I did some sessions in the pool, but that gym environment where people get annoyed if you hog the lanes was far from ideal. I knew I would get fit while completing the swim, but the first couple of weeks were hard. I didn't have the muscle memory for swimming, it was difficult to concentrate on my style, and I wasn't used to the waves or cold. Your daily food intake during the swim included whole packs of butter. How did you manage that?
I call them 'free calories', which include anything that you add to a meal that doesn't drastically change the look or size, but increases the calorie content. I had these all-in-one bagged meals, which I blended and added things like oil, butter, or coconut oil to – basically any sort of omega oils – plus sweet potato or pasta.
I still lost a lot of weight during the swim, but I just had to do my best. Eating was difficult because I couldn't chew – my tongue was swollen and I was seasick, therefore the process of chewing took too long so that's why everything had to be blended. You've said that there was only one time you really wanted to quit – when and why? How did you overcome that?
That was on day two, when everything should have been in my favour – tides in the right direction, no wind or rain, and plenty of places to rest. None of it went to plan. Tides were bad, the rain, wind, and waves came, and I couldn't get out of the water because of the huge cliffs in my way. That's when I started to think that maybe this wasn't possible.
Luckily I was wrong about that. As it was only day two, I hadn't learnt enough about the ocean at this point, and I was swimming too close to the shore. Once I started to swim three miles away from the coast, things got easier. It was a learning curve, all the way through. Obviously a challenge like this takes as much mental strength as it does physical – what's your biggest piece of advice for building mental strength for an expedition?
I think it's all individual. And you have to ask yourself one question: what do you want to get out of this experience? Take baby steps. If you can physically move your arms or legs forward, you're capable of travelling a metre. If you do that enough times a day, you'll make a few miles. Take your expedition day-by-day, metre-by-metre, rather than thinking about the bigger picture, because that will overwhelm you.
Did you have many opportunities to take in and enjoy the scenery during the journey? If so, what was a highlight?
There were so many, to be honest – everywhere was amazing! I had a lot of down-time, because the tides were running against me six hours a day. It's impossible to swim against a tide – you'll go backwards – so this was forced exploration time.
The first month in Cornwall was a highlight because when you're at sea you can access beaches that people on land can't reach, which is great in summer when most places are so busy in that part of England. The same goes for some many places further north, up the Bristol Channel, Ireland, and on to Scotland, which is so pretty. It was always my intention to make this not only about the challenge, but also about using swimming as a form of transport for a coastal adventure. I managed to strike a good balance between the two. If you could go back and see yourself five minutes before you started the swim challenge, what would you say to yourself?
I would tell myself to eat more! I really struggled to get enough food in me. I would also warn myself that it would take a lot longer than originally planned. Four and a half months of swimming dragged on a bit... You once wrote, 'I've realised I'm really good at being hungry, tired, cold, and wet' – what is it about these conditions that inspires you?
I'm a big fan of the human body. I find it fascinating to see how far we can push ourselves, from a biological, scientific, and mental point of view. These expeditions are like research in that sense – my way of finding out what the human body can cope with.
Before I took on these challenges, I always chose the easy route, and it made me miserable. Now I purposefully try to make my life more difficult because I'm too scared to go back to living an ordinary, non-challenging existence. And once you start taking on (and completing) these kinds of expeditions, you get addicted to seeing how far you can push your mind and body. You completed your first major expedition aged 30. What advice would you give to aspiring adventurers who think their age or inexperience is against them?
We're all a lot more physically and mentally capable than we realise, and once you take the first step you'll surprise yourself. You actually get better with expedition stuff as you get older anyway, because you know how to cope with life better.
I remember when I needed to cycle across the Aussie Outback, I thought 'Jeez, it's going to be hundreds of miles until I can get food or water or anything. How am I going to cope?' I was really nervous, but I soon realised that actually, I was surviving. You'd be surprised what you can cope with. You've now cycled and swum the length of Great Britain, and attempted to run it in 2014 but couldn't complete it due to injury. But you're trying again this year! How's the training going?
It's going well – I'm feeling strong. I start the run on the 20th March, and there will be cameras filming me – the footage will be aired exclusively on the Discovery Channel later in the year. This one completes the set for me, as the third and final leg in my ultimate British triathlon.
What I'm really looking forward to is the fact that this one's not a race. I'm not trying to break a record, which allows for a lot more exploration. While I'm still going to be aiming for one marathon per day, there's plenty of room for fun, which means meeting locals in the places I run through. I think that Britain is a pretty awesome island, and hopefully through this run I can show people that. Sean's new book Hell & High Water: Swimming the Length of Britain is out now.