I am fortunate enough to live a flat, five miles from my office. I am also fortunate to live and work in Surrey; safe, cyclist friendly roads which can be a pain in the car during rush hour but are a dream on the bike.
I first took up cycling to work not for fitness but out of frustration at the cost and time using public transport or driving to get to work took. Soon the benefits could be seen: not only did I get to stay in bed marginally longer when cycling as it was actually the most time efficient way to get to work but between petrol, train fares, bus fares and gym memberships I was saving £120+ a month. Additionally, I am doing my bit to help reduce my carbon footprint and personal CO2 emissions, something which we should all be thinking about.
On top of all this I was gaining at least 250 calories a day, and benefitting from a (fractionally) faster metabolism which never goes amiss!
Then I looked up the quantified benefits; it is a long established fact that exercise which is part of a daily routine is by far the most effective. Regular cyclists on average live longer and have fitness and health levels of someone up to ten years younger.
The Parliamentary Health Select Committee found in May 2004 that cycling to work or school is so effective that: “If the Government were to achieve its target of trebling cycling in the period 2000-2010 … that might achieve more in the fight against obesity than any individual measure we recommend within this report.” In line with this thinking there has been a massive push from the government to invest in cycling infrastructure as well as many companies operating schemes to help employees buy a bike and running 'bike to work' weeks. Last year there were statistics published quantifying the difference in weight between those who cycled to work and those who did not. Again one of the reasons for this is routine; not having to find the time to exercise ensures it happens and becomes second nature.
In short, I cannot recommend cycling to school or work enough. For more information about getting started as a cyclist, visit this excellent NHS page http://www.nhs.uk/Livewell/fitness/Pages/Cycling.aspx