There are many great cardio exercises to start a program with. For example; running, cross-country skiing, rowing, hiking, swimming, any number of machines at the gym. After running throughout high school and college, I developed a love for it. I also developed injuries that wouldn’t go away. So I became a cyclist. But beyond being good for you, it is one of the easier exercises on your body(read less wear and tear) so that you can keep up a daily program of it without injuring yourself. It is easy to fit into your daily routine. Most cities in America have some bike trails and paths to start on without cars, and as you progress you start to feel more comfortable around cars. This is when you want to start commuting by bike. Distances up to 10 miles are easily covered on a bike in reasonable time. By spending most of your free time fighting traffic, you can spend a little more time on your bike, racking up some great strength and cardio exercise(and usually able to zip by increasingly slow commuters stuck in their cars). I have experienced commuting in sub freezing temperatures as well as up to 115 degrees. It is a matter of acclimatizing and dressing appropriately (and knowing when to workout inside, too). The healthy vascular system copes easier with exercise and temperature extremes with less stress.
The benefits for the environment are well documented. We already know that we are addicted to oil. What we don’t see is the infrastructure of our government highly subsidizes automobile use. Whereas most advanced countries levy many of the taxes used to pay for road construction in the fuel prices, we have a comparatively low fuel surcharge, instead rely on general tax money to pay for roads. Our country was built on the backs of interstates and automobiles. But at a certain point, we got caught in the dream of automobile freedom, and got stuck in a nightmare instead. Besides that, keeping a relatively new car in the garage consumes 18%(on average) of our funds to keep running and gassed up. Another issue with cars we could do without is the fatalities and injuries. Besides helping to fatten our country, automobile accidents account for well over half of the injuries seen in hospitals (70% in my county), and a very large percentage of accidental deaths.
So get a good bike, one that fits well, is durable, and efficient (you’ll be more likely to ride more often if it is comfortable and not constantly breaking down). I recommend a good bike shop to get you started in the right direction. Some general guidelines are :Adjust the seat so that the knee angle ends up at 30 degrees(+/- 5 degrees) of flexion at the bottom of the pedal stroke with the foot angled slightly toe down. Another way to check seat height is to straighten the leg completely while the ball of you foot is over the pedal, your foot should be parallel to the ground. This method is cruder, but gets you in the right 25 to 35 degree range very nicely. The forward kneecap should be straight above the end of the crank when the crank is parallel with the ground. With the seat at the right height, the grips should be about the same level as the seat for a good do it all position. Arms should be perpendicular to the back when reaching out to the bars. These are a good guide to get started, but don’t take into consideration positions for cruisers, Townies, track bikes, or racing bikes. Seat height it still very important to get dialed, so as not to cause wear on the knees.
Start with general riding, to get familiar with your bike, traffic, and the routes in your area that are safe. Then start with some workout rides. The idea is to warm up, spinning and getting the muscles and lungs working together. Sometimes if your commute is short, the entire ride is a warmup. Just make sure that you take the long way in to work a couple of times a week to get a decent workout. After a 15 minute warmup, put it in a bigger gear (or spin faster on a track bike) so that you can raise the heart rate. The ventilatory threshold is what you want to pass. This means that your breathing jumps beyond the casual shallow breathing that you normally have, to a steady, deeper breath. You can still talk to someone without cutting sentences short, but work is occurring. A heart rate monitor gives you great feedback, but takes some time to learn what your numbers mean. As you roll into work(or school, or the store) do some easy stretches of the hamstrings, back, and quadriceps before locking the bike up.
I find normal roads and sidewalks are great for riding, as long as they have a shoulder so cars aren’t forced to wait or veer out of their lane to get around you. Of course some roads are barely able to handle the amount of cars on them, let alone a cyclist too. Maybe if we get enough people to “Go With the Flow”, more room will be made for us cyclists.
Other types of exercise are just as good for you, but harder to fit into a daily routine than bike commuting. Whatever you do for exercise, what may seem like work at first becomes easier and more fun as you progress. You may notice that you have to go faster and further than you did previously to reach respiratory threshold and get a decent amount of time of exercise in. It is important to keep in this aerobic heart rate zone (55-75% max heart rate) for at least 4 hours a week to see steady progress at first. By all means exercise more if you feel like it, but don’t get into the weekend warrior type schedule, keep exercising throughout the week. Some resistance work is important to keep and improve muscles, tendons, and bones. Usually twice a week is good.