Sarah McMillan arrives at work promptly each morning. Feeling energetic, healthy and in good spirits, the 34-year-old enthusiastically sits down at her desk and faces the busy working day ahead.

"I am raring to go," she gushes. "I feel alert and I'm always in a good mood."

For McMillan, a development project worker for Men's Health Forum Scotland 10k, the morning transformation has come about since she began cycling to the office every day. Instead of automatically jumping into the car for the three-mile journey to the office, she pulls on her waterproofs and pedals from Glasgow's west end to the east end.

McMillan, who made the switch to cycle commuting a year ago, says: "It's a surprising discovery to be honest, to find myself more energetic rather than less.

"I remember I used to feel so sluggish arriving at the office having driven from home but now I have entirely the opposite feeling."

There have been other benefits for McMillan. "I have saved hundreds of pounds because I use less petrol and I've lost a stone in weight. As a diabetic I have also reduced my dependence on insulin. I have also reduced my carbon footprint, which is a great plus point for me personally."

According to a number of recent reports, McMillan is not the only cycling commuter convert. One survey by Sainsbury's Home Insurance revealed that more than three million commuters in the UK have started cycling to work in the past 12 months.

The research found that one in eight workers has switched from bus, train or car to commuting by bicycle. Their principal reason is reported as cost-saving - on average, pedalling to work saves £33.70 per week.

Meanwhile, Cyclescheme, the UK's main provider of tax-free bikes for the government's Cycle to Work initiative, reports an increase in bicycles bought over the past three years. The scheme offers staff the opportunity to buy a bike at a tax-free price and by paying regular instalments via their employer.

In 2006, 3238 bike vouchers were issued through the scheme. The following year, 16,161 employees took advantage of the initiative and, by 2008, the figure was 36,678.

A popular city bike store, Edinburgh Bicycle Co-operative, reports that hybrid bikes, which are most commonly used by urban cycle commuters, now account for around one-third of all bike sales, up from a quarter four years ago.

And even rural bike shops are witnessing an increase in sales to commuters. Steve Macdonald, who owns Square Wheels, in Strathpeffer, has seen a 15% rise in hybrid and road bike sales through the shop and via his online store.

In particular, he sells many bikes through the Cycle to Work scheme. Macdonald says: "Increasingly, I hear customers talk about cycling as a cost-cutting proposition. With many feeling the pinch of the recession they see cycling as a direct benefit in terms of saving money on petrol.

"In the current economic climate, bike sales must be one of the few areas bucking the recessionary trend."

Despite living 12 miles from her workplace at Inverness Business Park, Square Wheels customer Renate Jephcott still uses her bike to commute. Jephcott, a landscape architect for Forestry Commission Scotland, cycles the first four miles from her home to Beauly train station. Here she boards the train for Inverness, along with her specially-bought Dahon folding bike. At Inverness, she disembarks, unfolds the bike and cycles the final two miles to work.

While the bike-plus-train trip has undoubtedly saved Jephcott, 41, many hundreds of pounds over the past two and a half years, she states that her primary motive was environmental. She explains: "Many people who live in the country end up driving a car around on their own with no passengers. It's just a fact of life for a lot of rural dwellers.

"But I don't like the impact that this has in terms of carbon emissions. I thought I would try to work out a way to get to work by other, more green, means."

For McMillan, the journey to work by bike can take one-third less time than by car. "During Glasgow's busy rush hour, it could take me half an hour or more to drive to the office," she says. "But by bike it's only 20 minutes. I use bike lanes and I am not held up in long queues. I think this is one of the advantages of cycling that many drivers overlook."

Another cyclist, Yvonne Press, reports that her daily commute is not only "slightly faster" than by car but it's also "a great deal more convenient". Press, 30, an account manager for PR firm Niche Works, says: "Because I cycle, and tend to use purpose-built paths and bike lanes, I know to almost the exact minute how long the journey will take me. If I'm a little late leaving home, then I can catch up by cycling harder. I think cycling is by far the most convenient and punctual method over this kind of distance."

Press, too, has realised the cash-saving benefits of cycling, especially as she bought a reconditioned bike from the Bike Station in Edinburgh for £60. She is also delighted by the health benefits of her commute. "I've lost weight and become fitter without paying much attention because cycling is now so much part of my life," she says.

Get on your bike

Bike It doesn't need to be expensive but ensure gears and brakes are of a good quality. You will pay more for makes such as Shimano but they will better withstand the Scottish elements. Look for a bike with a comfortable riding position. A "hybrid" has the advantage of combining a road racer bike with a mountain bike. Ideally, your bike should come with a chain guard, a bell and a bike-rack so that you can attach a pannier bag. There are other bikes specifically made for the commuter that have built-in, low-maintenance hub gears and internal roller brakes. Many employees will have access to the tax-free Cycle to Work scheme. See Check out bike recycle workshops - for example, the Bike Station in Edinburgh ( - for reconditioned bikes.

Helmet Always buy it new. Most brands have a starter-priced helmet.

Jacket If you're cycling on busy roads, a brightly coloured jacket is advisable. Aim for one that is also waterproof and breathable.

Lights Being seen is vital in busy commuter traffic.

Learn the skills The Cyclists Touring Club (CTC) offers tips on It is also possible to sign up for a three-stage CTC training programme called Bikeability to improve confidence.