Life cycle: Getting on your bike could add years to your life

- Saddle up for the environment
- Why aren't we all at it?

If helping the environment isn't enough of a reason for you to take up cycling, why not take a moment to consider the potential health benefits.

Cyclists live on average at least two years longer than non-cyclists, their level of fitness is equivalent to being 10 years younger and cycling at least 20 miles a week halves the risk of heart disease compared with non-cyclists who take no other exercise.

So, given the overwhelming medical evidence, why aren't more people perched on their saddles increasing their fitness and lifespans?

Well, while it mainly looks like laziness, there are some justifiable concerns when it comes to health and cycling - almost exclusively due to the non-sustainable transport options sharing our roads!

Scarcely a day goes by without a new story on obesity hitting the headlines. The UK's collective girth is definitely widening - adult obesity has quadrupled in the past 25 years and now includes 22 per cent of the population, while three-quarters of us are overweight.

This is worrying because of the health implications - an estimated 30,000 deaths a year - and the fact that it is hitting our youngest citizens, with childhood obesity tripling in the past two decades. The solution: diet and activity.

Most of the stats that show how healthy cycling is are often derived from more general evidence about the benefits of activity - reduced mortality, heart disease, cancer, blood pressure - but some specific studies have found cyclists are actually even better off.

And the advantage of, say, hopping on your bike to go to work or shopping is that you get your exercise within your normal daily routine. And can enjoy the irony of those stuck in traffic on their way to riding an exercise bike in the gym - as you glide effortlessly past the jam.

So how much lard will you lose if you cycle? Obviously, it depends how much you ride but cycling moderately for just half an hour a day burns about 150 calories, which would add up to the loss of over 5kg (11lb) of fat in a year.

Don't expect to turn into a rake-thin Lance Armstrong lookalike (David Cameron hasn't yet), but do expect to be healthier, fitter and slimmer than you would be otherwise.

You might argue that it's hard to enjoy the fruits of this exercise if you've gone under a bus - not to mention the pollution - but a Cycling England review found that in 2003 there were around 40,000 deaths due to physical inactivity and only 113 deaths due to cycling.

The most reasonable measure of risk (in terms of time spent travelling rather than miles travelled) shows that both car and bicycle users have comparable levels of risk: one death every 20,000 years of regular car or bicycle use.

And all the available evidence points to the danger falling, since, according to Jacobsen's Growth Rule, the more cyclists there are the fewer accidents there are.

For example, double the amount of cycling and the risk per cyclist falls by 34 per cent.

And in terms of inhaling pollutants, an Imperial College study found that those in a car are exposed to 40,000 ultrafine pollutant particles per cubic centimetre of air compared with just 8,000 for cyclists, while taxi and bus passengers face 100,000 particles per cc.

This surprising finding is due, it is thought, to the fact that air is drawn into cars at the level of other vehicles' exhausts.

If you still have doubts about incorporating cycling into a daily routine, the very broad Copenhagen Study in 2000 (over 35,000 men and women aged 20-93) found: "even after adjustment for other risk factors, including leisure time physical activity, those who did not cycle to work experienced a 39 per cent higher mortality rate than those who did."