The first weekend of December is about decorating the Christmas tree in the comfort of a warm home before grabbing a coffee and then doing the Christmas shopping.

At least this is how it is for most earthlings. For us, it is very different. Roxy, my 60-foot carbon-fibre racing yacht, and I - as well as 20 other intrepid adventurers competing in the Vendée Globe - are a week into the notorious Southern Ocean. I am sailing these inhospitable waters for the first time on my own with Roxy.

Known for its storms, massive seas and icebergs, the Southern Ocean is one of the most isolated and unforgiving parts of the world. In the past few days, Roxy and I have been rocketing along in our first, but not last, Southern Ocean gale. The objective is to go fast, but as safely as possible. The optimum speed is somewhere between “comfortable” and “dangerously out of control”. So, as the wind builds, you slip between these modes, and when you get too far into the second, you reduce sail to return towards “comfortable”.

My first big sail change in this wild place was on a cold, black, windy night. Roxy was screaming along and as I scrambled around the cockpit to prepare to roll away my front sail, the only thing I could see were the breaking waves that were alight with phosphorescence.

It was then that I had my first real moment of solitude. I stood up and took in my surroundings. I felt terribly small and vulnerable, miles from anywhere, aware that no one knew that I was on Roxy's deck, working my sails. Luckily, there is not much time for reflection. Roxy face-planted into another wave and that stirred me back into action. And so life goes on out here, at the bottom of the world, one month into our circumnavigation of the globe.

But day-to-day life continues, just as it does “on earth”. My living space is just a bit different. The office and bedroom (a chart table), the kitchen and bathroom (a kettle and bucket), are all in a space two metres by three metres.There is no heating, so the cold, coupled with the physical work of sailing, means that I am burning more than 4,000 calories a day. Eating to match that is quite a challenge - thank goodness for my mum's fruit cakes (she made me six). My office day on board Roxy takes up a lot of time: weather-forecasting, strategy, decision-making, checking the boat and running repairs.

I opened the No7 door on my advent calendar yesterday. My little sister Debbie gave it to me and it is stuck on an instrument display I am not using. It will soon be Christmas, and I am revelling in the fact that this year I have escaped Christmas shopping. I will, however, miss that fun atmosphere as everyone bustles around brightly lit streets.

As I write, we are less than 500 miles behind the leader. It might be a day and a half of sailing on paper, but in a three-month race, it is possible to catch up. I have been promised a pair of Jimmy Choo shoes by a friend if I finish in the top ten: I won't let them go that easily.