Jo Jackson fears the English winter, but she is adamant she can weather this year's cold snap and arrive at March's Olympic trials firing on all cylinders.

It was this time two years ago that heralded a disastrous period in Jackson's burgeoning career as her asthma escalated into re-occurring attacks, chest infections, flu, sinus trouble and popped ribs.

The 25-year-old long-distance freestyle specialist had just won individual double silver at the World Championships, a year after taking Olympic bronze, and stolen the limelight from Rebecca Adlington.

However, her form plummeted and she failed to medal individually at the European Championships and Commonwealth Games in 2010, while that was also the case on her return to the worlds this year.

Jackson, who is supported by British Swimming's principal partner, British Gas, insists the worst is behind her though, swimming her fastest 200m freestyle time in two years in June to book a world swim, and has long been using a revolutionary asthma medication.

Yet Jackson is not immune to winter bugs, having just recovered from one, but she is certain time spent in Florida and Tenerife between now and the Olympic trials will stand her in good stead.

"Illnesses do go around and quite a few of us in my training group have had chest infections," said Jackson, who, as part of British Swimming's Big Splash campaign, is urging people to take up swimming for 30 minutes once a week.

"I have had a bit of a chest infection and it has dragged on, but I have still managed to train, I wasn't out of the pool and it didn't take over and I am much better now.

"Sometimes when I get ill I am fearful after what has happened to me, and I hope it doesn't linger, but nothing has been too bad and I have learnt how to do deal with it.

"It has got a lot better recently and I am still training and doing things and these things seem to go pretty quickly now - I've learnt from my past experiences.

"Going away to hot weather and staying away from bugs will be good. I'll be off to Florida soon and then Tenerife after Christmas.

"I have been out to where we are going in Florida a couple of times before and we will get to train outdoors in a 50m pool and we'll just be able to concentrate on swimming for four weeks."

At July's World Championships, which earlier in the year Jackson hadn't expected to qualify for, she failed to make it out of the heats in the 200m freestyle.

She returned to help the British 4x200m freestyle team finish sixth, and book an Olympic spot in the process, and believes there is plenty of cause for optimism over her individual form.

"I definitely got better throughout the year, it was tough to start off with and you always have your ups and downs but things progressed and it is going really well now," added Jackson, who is helping to promote the 1,000 pools across the UK offering Big Splash events, taster sessions, and special offers to customers.

"My first swim at the World Championships wasn't great but I got into the meet with a few really positive swims and I can take a lot from that.

"My confidence was pretty low last year but I am definitely building on it and I have gained a lot from the past few months with the training group I am in, they are definitely helping me."

* British Swimming's Big Splash campaign is supported by principal partner British Gas, and supporting partners Kellogg's and Speedo. For more information on great swimming activities and offers visit bigsplash.co.uk