Roger Nilson is relaxing in the sunshine, casually picking at a slice of carrot cake as he sits on the deck of Telefonica Black. He has been in full flow for more than an hour now, recalling heart surgery, the vices of Indian gurus and the time a Romanian mafia boss chased him with a machine gun. No one has sailed in more editions of this race than the 60-year-old doctor, but he has started worrying that he might do another.

"It is no problem if nobody asks you, but the problem is if somebody asks you," he says. "It is difficult when you are given the choice. Hopefully no one asks me again.

"I don't think I would do it, but I do not know for sure how I would respond if someone asked."

It's a long story that Roger cuts short. "I have an addictive personality. It brings consequences."

The sailing tale goes back to Christmas Day 1974. Roger was 25 at the time and two years into medical school. He decided to visit his parents' house and while there a documentary about the Whitbread Race came on the television. It was a few months after the very first edition of the event and Roger, who had been racing offshore for three years, was captivated.

"I had wanted to do this kind of race for many years, but there never was one. I had never heard of this event at that time, but it was exactly what I had been dreaming of doing."

By 1977, ahead of the second edition, he was set to join a team when the skipper got sacked and plans changed. But a meeting a year earlier with Skip Novak, the now legendary American skipper, would soon open a door. The pair had been sailing onboard Bumblebee when Roger got a wire sheet caught around his neck and was pulled over the side. Novak resolved the situation and Roger thanked him with a few drinks.

They struck up a working relationship and Novak asked Roger to join him on a campaign in the 1981 race. Ultimately the project was scrapped because of financial issues. "Not very good," Roger says. But his race debut still went ahead that year when Novak was brought onto the Alaska Eagle project and took Roger with him. "It was a strange crew," he says. "We had Mexicans, Californians, English, everything. We did not get on even before we left. A psychological nightmare.

"It was a different era in the sport. The boat was built for the race, but still equipped like a Swan boat. There was a full interior with a mahogany table. We had a guy cooking, a very good cook, and he was probably drunk most days. The boat was filled with wine. And we had cabins; I shared with another guy and we had sheets, blankets, pillows, drawers, carpets, book shelves. There was also a special working cabin for the navigator, so I had two cabins and two beds."

In the years that followed he would navigate Drum, the team entered by Simon Le Bon and skippered by Novak; fund and race The Card; initiate and skipper Intrum Justica during leg one; and take a leading role ashore and onboard in the Swedish Match project. He returned for a sixth straight race in 2001-02 with Amer Sports One, Grant Dalton's star studded team, but was not involved in the last event.

"That was pretty devastating," says Roger. "It was the first time since '77 that I was not asked before the start. It was like an abstinence and it was very hard."

One of Roger's therapist thinks he is addicted to ocean racing and its thrills; he has been involved in nine round-the-world races. He does not seem so sure, but concedes he probably is. "I did not expect to be coming back to do a seventh Volvo race," he says. "I find it hard to say no. Maybe it is an addiction."

He had plenty of excuses to opt out of this current event. He had been contacted in October 2007 by Bouwe Bekking, asking if he would be the Blue boat's media crewmember. The idea fell flat, but Bekking returned with an offer of the navigator's position on Black. Nilson, against his fiance's wishes, said yes. Then he had triple bypass surgery on his heart. "The doctor said I would be okay to sail, but there are good reasons not to. I am 60 and did not expect to be in this race. I perhaps could have said ‘no' after the surgery, but maybe this is an addiction for me. Certainly I still enjoy the racing a lot."

To Roger, a fully qualified orthopaedic surgeon, addiction is not a lightly used term.

"Addiction is a temporary escape from painful thoughts and emotions," he says. "The consequences are the problem, not the action. You can drink a lot without being an alcoholic.

"You have feelings inside you, like emptiness, meaninglessness, loneliness, hopelessness. If you have an addictive personality you will find something you know will make you feel better fast, like a short term "medicine", escaping from painful thoughts and feelings."

It has manifested itself in many areas of his life and career. He has been a "workaholic", ploughing his efforts into campaigns. And he developed an "addiction to media attention" during his work on the successful campaign with The Card. His addiction to sex and love brought some of the consequences that forced him to fully confront his psychology.

"When I sailed with Grant Dalton in 2001-02 I had a very messy situation with some women in Miami and then it got worse in Baltimore. Because of the stress I got acute severe back pain and I said to Grant I couldn't sail but he said I should stay onboard anyway. I didn't do very well. It was a consequence of my addiction.

"Many men are impressed by this kind of thing. If you shoot heroin many people don't stand up and say ‘great', but if you have a lot of beautiful women many men are impressed.

"I had a deep realisation in 2004 that I had sex and love addiction. I was 55 and met some quite young girl in the airport in Stockholm and she invited me to go to Romania. She was a gorgeous 24-year-old and after an hour meeting I decided to go to Romania to visit her.

"I did not know her jealous ex-boyfriend was some kind of mafia head and he turned up at the apartment with a machine gun and I sneaked out. There was a bit of a chase. I was hiding in a small hotel in the mountains for five days. It was what I mean by consequences of an addiction."

It is something he is tackling by using a 12-step program, a protocol that helps him "avoid following addictive thoughts and find more healthy values in life. Rather intimacy and honesty than intensity in a love relationship."

Roger has for a long time been deeply introspective. For several years he has sought the interpretations of therapists and made numerous visits to sages and gurus in India. "One of the gurus had a sex addiction," he says. "One guy was addicted to power.

"But others were great, and brought me close to the teachings of ‘Advaita', the teaching of non-duality. I think this is the ancient philosophy which true, unconditional love is based on."

Ultimately, the 12-step program is working best for Roger. He got married in 2008, two days before the race started, and says he now feels "very comfortable with myself".

It's not particularly unusual that Roger has addictions. Plenty of successful people, particularly sportsmen, have obsessive tendencies, the extension of an intrinsic desire to train and practice and reach a goal.

Indeed, it is his addiction to work that has contributed to Roger simultaneously achieving a career in medicine and surviving across three decades at the top level of an extremely tough sport.

What is different is the way Roger talks about it.

"I do not mind what people say," he adds. "I do not regret anything; do not feel any guilt or shame anymore: a big freedom."

It remains to be seen if Roger does another race.