It's no easy task to trek to the base of the world's highest mountain, especially when you have asthma. Our intrepid explorer Jane Kirby reveals how she battled the cold and the lack of creature comforts to raise money for Diabetes UK.

It is below freezing in the tent and it's taking me all my strength to get out of my sleeping bag. I reach for my water bottle and give it a good shake before quickly realising the water is frozen solid.

It's 6 o'clock in the morning and I'm only part way through one of the toughest experiences of my life - trekking to Everest base camp.

I'd love to roll over and go back to sleep for a few hours, but there's no chance of that as a sherpa unzips my tent door and passes in a mug of steaming hot tea and a plate of crumbly, home-made biscuits.

This is a typical wake-up call for trekkers heading towards the highest mountain in the world.

It takes at least eight days to get from the tiny Nepalese village of Lukla to the icy camp at the base of Mount Everest.

Every morning, the sherpas do their job and set about making porridge, while a bunch of bleary-eyed trekkers pack up their kit.

I am one of 17 such people undergoing this challenge to raise money for the charity Diabetes UK. Most people in the group have diabetes themselves or a close family member with the condition, which causes complications like blindness and heart disease.

My own mother has been insulin-dependent since the age of 18 and suffered a heart attack two years ago. The thought of losing her shook me up for a long time and it took months for me not to worry every time the phone rang.

But the flipside was that I became determined to grab life's opportunities with both hands, including agreeing to take on this: my first expedition.

Naturally, I've had a few reservations... for a start, I'm asthmatic and scared of the cold and dirt. I've never been camping before, had not set foot in a gym for three years before signing up and am more used to high heels than hiking boots.

But after nine months of hard of training in the gym - spin and body pump classes and hours on the cross trainer - I feel somewhat prepared to face the task ahead. I've also upped my dose of steroid inhalers in the hope they will help me cope in high altitude.

Our first trekking day sees us leave Lukla airport and start on the trail to the village of Pakhding. A couple of wooden teahouses can be seen serving hot drinks to thirsty trekkers but I soon realise there will be no time for stopping.

Most of the hike is through lush green forest, with a few uphill climbs that lead to views of snowy mountains.

We reach Pakhding at about 4pm and there is just enough time to set up our sleeping bags and change into thermals before the temperature plummets to around minus 10 degrees.

"I have never been this cold in my life," I say to myself, as I slip into my tent after a delicious dinner of pizza and roast potatoes. But neither, I think, have I ever seen the Milky Way before... or a sky this blue.

The following day sees us heading towards Namche Bazaar, the most developed village along the route to Everest. Namche is set in a natural amphitheatre and is the last place we will experience one luxury: hot running water.

The trekking facilities so far have been pretty spartan - it's been three days since I last took a shower and the toilets are of the "squat and drop" variety (a freshly-dug hole in the ground).

Every evening, the sherpas bring us tiny bowls filled with hot water to wash our feet and I secretly use mine for a quick strip wash. It doesn't really do the job properly and there's no hope of washing my hair for the next week, but I am so thrilled by the scenery that I haven't noticed too much. Anyway, baseball caps are wonderful inventions.

More than the dirt, it's the freezing cold nights that are bothering me and I come close to crying one night, alone in the tent at 3am.

Falling asleep is impossible because although I can wear clothes on most parts of my body, I can't cover my nose and mouth, which are so cold it's painful. After a battle with my emotions in the early hours, I vow not to let the tears fall. To make it through this trek I need to be mentally as well as physically strong.

The next day's hike is a difficult one, mostly due to the fact we are starting to feel the effects of high altitude. At 3,440 metres (11,286ft) above sea level, the air has become noticeably thinner.

A few of our group have been complaining of headaches and we are all on a strict regime of four litres of water a day to combat the pain. It's impossible to tell beforehand who will suffer from altitude sickness; it varies from person to person and bears no relation to fitness. Mild symptoms include nausea and headaches but the more severe ones are irregular breathing, particularly at night, a total loss of appetite, and insomnia, which gets worse the higher you climb.

As our bodies fight to adjust to the lower oxygen levels, the most obvious sign for us is that we are moving extremely slowly. A tiny hill that I would usually sprint up at home now feels like I am attempting to climb Mount Everest itself.

Each day after Namche becomes a milestone as we pass through the villages of Tengboche, Dingboche, Lobuche and Gorak Shep. On our way to Tengboche, we catch our first glimpse of Mount Everest - 8,848 metres (29,021ft) of icy glory.

The highest point of Everest sits in the jet stream, a wind current that regularly reaches more than 200mph. The result is that the mountain looks like it's smoking a pipe, with white plumes of smoke coming off the top.

The final day's hike to base camp is a punishing eight or nine hours round trip, during which time many of us feel ready to collapse. By now, aches and pains have developed in muscles I never knew I had, and my brain feels foggy due to the thin air.

I am getting just 50% of the oxygen my body enjoys at sea level, which is 5,365 metres (17,597ft) below. However, my asthma has, surprisingly, been holding up fine thanks to the strong inhalers and the fact the gym has made me pretty fit.

Around 2pm on base camp day, I begin to wonder what on earth I have been thinking in doing this trek. Then, suddenly, I spot the craggy outline of the Khumbu Icefall in front of me, which is one of the most treacherous parts of Everest to climb. It is a sign that we have actually reached our destination and there is a relieved look on everyone's faces.

The team has raised more than £60,000 for Diabetes UK and we can now all take home the feeling that we can achieve almost anything. In fact I'm thinking I might - just might - climb Kilimanjaro next year.