Back in 2005 I was subjected to a brutal psychological experiment. I was put into solitary confinement for 3.5 months. I was set a series of physical and psychological challenges that pushed me far outside my comfort zone.

I slept on a bunk only a little wider than my body, and during the night I was woken up at unpredictable intervals until sleep deprivation started to affect my cognitive processes – leading to loss of focus and attention, indecisiveness, and difficulties with solving problems.

And I had no entertainment – not even an iPod – so I had nothing but my own thoughts to entertain me for 103 long days. I was allowed one short phone call a day, until the last 24 days when even that privilege was withdrawn.

Why on earth did I submit myself to this horrendous psychological torture? They weren’t even paying me money – in fact, I had to pay to do it.

The truth is that this experiment did not take place in a laboratory. It took place in a 23-foot rowboat, which I was rowing 3,000 miles across the Atlantic from the Canaries to Antigua. And as if that wasn’t enough, I then went on to become the first woman to row solo 8,000 miles across the Pacific, and then another 4,000 miles across the Indian Ocean.

So, what was the point of this self-inflicted experiment?

I had a theory that I was capable of far more than I had achieved so far. This wasn’t out of any sense of being special, or talented, or gifted, which I most certainly wasn’t. It was more of a hunch, that if I put myself to the test, I could throw off my self-limiting beliefs, my lack of self-esteem, my fear of failure, and do something out of the ordinary. I felt there was something more to life, if only I could reach out and grab it.

But the only way to find out what I was capable of what to push myself beyond my limits – to stress test myself.

And the rather obvious characteristic of stress tests is that they involve a lot of stress. Even though I had done extensive research and rigorous preparation, the Atlantic crossing was way harder than I could ever have expected. It was the year of Hurricane Katrina, and there were more named storms on the Atlantic that year than in any other single year since records began. Pretty soon, that stormy weather took its toll on my equipment – all four of my oars would break before halfway, as did my stereo, camping stove and satellite phone. I had tendinitis in my shoulders and saltwater sores on my bottom.

Yes, as stress tests go, it was perfect.

The good news is that it is the way we perceive a situation, not the situation itself, that dictates our stress levels. Something is only stressful if we respond to it by getting stressed. And once we’re aware that stress is a choice, we’re halfway to managing it.

A really important thing I needed to learn was that there were some things I could control, and some I couldn’t, and there was no point in stressing about the things that I couldn’t control.

I used to have a very strong internal locus of control – a feeling that I was in charge of my destiny, through hard work and having a plan. The opposite is having an external locus of control, where everything is somebody else’s fault or just plain bad luck.

Psychologists reckon that being somewhere in the middle – knowing what is inside and outside our control – is the best way to be happy. All I can tell is that being in the middle of an extremely unpredictable ocean, when you’re a control freak, does not make you a happy rower.

Early on I took it very personally that the ocean was being so mean to me. It seemed to know just what to do to annoy me, slopping a wave right into my dinner mug, or soaking me just as I was about to go into the cabin.

It was even worse after my camping stove broke. I could still use my freeze-dried meals, but I had to rehydrate them with cold water instead of boiling water – which I would not highly recommend. Because I was using cold water, it would take several hours instead of ten minutes for the meal to rehydrate. So then when a wave came along and swamped it just as I was about to eat it, it was really annoying. But I’d have to eat it anyway.

Eventually I realised that the ocean is not in fact a sentient being, and wasn’t rearranging the laws of physics specifically to teach me a lesson. The ocean was just doing what oceans do, and I had to get on and do what rowers do, namely keep sticking the oars in the water.

This is how I think of it. You’ve got the circle of what you can control, and you’ve got your circle of what you can influence, and outside that is everything else – the things that you can’t control. And a lot of how you deal with stressful situations is about how accurately you assess which category something falls into.

There are times when it’s good to have a strong internal locus of control, and other times – not so much.

The wind and the waves – at first I’d put them in the wrong category. I took it personally that they seemed determined to thwart me and piss me off.

But of course that’s not the way it works. When I realised that the wind and the waves were out here, in the realm of “can’t control”, it was such a relief. I would occasionally let loose a volley of very bad language at them, just because it made me feel better, but I turned my attention and focus to what I could control, and what I could influence.

I had a whiteboard on the boat, on the bulkhead in front of my rowing position, which I used for writing up mileage targets and inspirational quotes. One of my favourites became that prayer about having the courage to change the things we can, the serenity to accept the things we can’t, and the wisdom to know the difference. Wise words indeed.

Roz Savage MBE FRGS is an ocean rower, environmental campaigner, author and speaker. She holds four world records for ocean rowing, including first woman to row three oceans: the Atlantic, Pacific and Indian. She has rowed over 15,000 miles, taken around 5 million oarstrokes, and spent cumulatively over 500 days of her life alone at sea in a 23-foot rowboat.

A latecomer to the life of adventure, Roz worked as a management consultant in London for 11 years before deciding there was more to life than a steady income and a house in the suburbs. Since embarking on her first ocean in 2005, she has braved 20-foot waves, been capsized 3 times in 24 hours, and faced death by dehydration when both her watermakers broke. Her hardships have forced her to find the strength and determination to overcome everything – especially herself.

Her first book, “Rowing The Atlantic: Lessons Learned on the Open Ocean”, was published in 2009. Her second book, “Stop Drifting, Start Rowing: One Woman’s Search for Happiness and Meaning Alone on the Pacific” was published by Hay House in October 2013.