I feel I have to take full responsibility for the poor weather writes fitness blogger Jamie Johnston.

In my last blog I wrote about how to cope with exercise in the warm weather and clearly I ended the summer. Sorry. I also may be responsible for the increase in Rickets.

Yes, you heard me correctly. A study this week showed increasing levels of Rickets, which is caused by a lack of vitamin D and is most commonly associated with growth deformities such as bowed legs.

However it also causes bone weakness and fractures in adults. Most of us produce vitamin D through exposure to sunlight, so if there’s too little sun we can’t produce enough and develop a deficiency.

And as the nights draw in, it becomes really easy to stay at home, eat comfort food and avoid exercise. It’s definitely less enticing to go for a bike ride, walk or run if it’s dark, wet and less than sultry. What we need is motivation or emigration.

And seeing as a little motivation is usually cheaper than emigrating to Spain, I wanted to offer ideas to stay fit as the days shorten and the weather cools.

I once had an office job in a basement, where I was expected in by 8am and couldn’t leave before 5pm. I literally didn’t see the sun apart from the weekends. It was when I developed fangs and an aversion to garlic that I knew I had to do something! The only thing that saved me was a lunch-time walk.

Just making the effort to walk round the block for half an hour stopped me from going completely insane. Who knows, it might have also saved me from bandy legs. So try making time for a proper lunch break to grab some fresh air.

You might also commit to a regular activity while there is still some warmth in the air and your motivation is still a little higher. Consider joining a friendly 5-a-side football or netball league so you get out at least once a week for a run around.

Set yourself a fitness challenge. You might be too late for the Wolverhampton Marathon which is next week, but there’s plenty of other challenges. October sees the Birmingham half-marathon. There’s also the Suicide Six which is an epic struggle through the Dudley mud in November or aim further ahead for the London or Stratford marathons in April.

Whether it’s just a regular brisk walk, a long-distance race or something in between, now is the time to start a fitness habit before the weather puts you off starting completely. It won’t just save you from a spare tyre, it might also save you from Rickets.

Jamie Johnston runs At Home Fitness, providing personal training across the West Midlands and Staffordshire. See www.athomefitness.co.uk for more details.