People who are new to exercise often see the stationary bike as an inviting way to get their cardio workout. You get to remain seated, and recumbent bikes even allow you to lean back against a comfortable chair. There's no impact to stress your joints, and because it's nonweight-bearing, you might not get fatigued as early as you would with other forms of exercise. The stationary bike can be a valuable weight loss tool, but you only get out what you put in.
Not Just Your Thighs
Cycling, like any other exercise, can help you lose weight if it puts your body into a caloric deficit; but there's no guarantee the weight will come off your thighs first. Since cycling can help build muscle in the lower body, it can help thighs appear firmer and tighter once excess fat is lost. Controlling your calorie intake will speed up results; or at the very least, stop you from undoing your hard work by eating too much.
How hard you work directly correlates with how many calories you'll burn. A leisurely pace while you peruse your favorite magazine will burn only about 177 calories per hour for a 130 pound person, but picking up the pace to a moderate intensity will burn 413 calories per hour. Most of your workout should be done at a moderate pace, but adding speed intervals can increase your overall calorie burn -- a very fast race pace, going as fast as you can, can burn 739 calories per hour, so sprinkle some sprints into your usual routine.
The amount of time you spend on the bike clearly dictates how many calories you'll burn. That 739 figure is for a whole hour at breakneck pace -- hopping on the bike and going all out for 10 minutes won't burn nearly as many calories. The generally accepted guidelines say you should do at least 30 minutes of moderate cardio five days per week to maintain heart health, but 60 to 90 minutes per day might be necessary to trigger weight loss. An hour of steady-state cardio is usually enough for most people, but adding the speed intervals can help you burn the same amount of calories in as little as 30 minutes.
Change It Up
Doing the exact same workout day after day can lead to boredom, and it can also cause you to plateau because your body doesn't see the workout as providing much of a challenge anymore. Experiment with different programs on the bike, or take an indoor cycling class. If the weather permits, take a road bike out for a spin. For even better results, cross-train with running or swimming to challenge your body in new ways.