It shouldn't surprise you to learn that, strictly speaking, bike riding can't increase your height --- if it could, the riders in the Tour de France might become basketball players instead. However, riding a bike is a great form of aerobic exercise that can also stretch and elongate your leg muscles. While it probably won't make you taller, it can give you a leaner, more toned physical appearance.
You might have seen this myth posted and debated in online health forums: Bike riding increases your height. However, no scientific studies performed by reputable medical professionals have proven this theory. In "Life-Span Human Development," authors Carol Siegelman and Elizabeth Rider explain that both heredity and your environment play a role in how tall you'll be. For example, someone with genes that code for a height of 6 feet might still be short if malnutrition prevents those genes from being expressed. However, you can only exhibit traits for which you bear the accompanying genes. In other words, if you don't have the genetics for a certain height, nothing you can do will boost you to that height naturally.
Although riding a bike can't make you taller, it can make you slimmer. In "Smart Cycling: Promoting Safety, Fun, Fitness, and the Environment," the League of American Bicyclists writes that on average, cyclists burn about 400 calories an hour. Cycling also builds muscle; once you've built up those muscles, they burn more calories than fat even while you're at rest. The faster you pedal your bike, the more calories you burn. The League estimates that pedaling at 10 miles per hour burns between 360 and 420 calories per hour, while pedaling at 13 miles per hour can burn as many as 600 to 660 calories per hour.
The League of American Bicyclists recommends new cyclists start slowly. If you're new to fitness riding, they suggest you start by going on a ride every other day. As your fitness level and comfort with the bike increase, you can ride five or six days a week. In terms of mileage, they suggest you start with a gentle ride of two to five miles and increase your riding distance slowly over time. Strive to add about 10 percent to your mileage total per week.
You'll do more than tone your thighs with all that pedaling. According to the New York City Department of City Planning, bikes are an extremely efficient mode of transportation. The Department notes that people who bike to work often arrive with increased alertness, eagerness and ability to work, in addition to the increased fitness level that often allows for fewer on-the-job injuries. Bikes produce zero pollution, use no fossil fuels and don't result in the same noise level as cars and trucks. Advocacy group Transportation Alternatives estimates that it costs frequent riders about one fourth as much to bike as it does to drive, saving them just over $1,000 per year.