In order to achieve overall leanness, you need to lose excess body fat. Losing body fat is accomplished by doing the right amount of cardio exercise each week to burn off the extra calories and fat. The key to the best cardio workout for a lean body is to choose exercises that are constantly challenging your body -- and that you also enjoy.
Not all cardio is created equal. While steady state cardio can be beneficial, your body will eventually adapt to working at the same pace every workout. Keep your body guessing by adding intervals to your workouts. Intervals are short bursts of speed followed by a period of recovery time, so they can be added in to almost any cardio workout. If you are on the treadmill, for example, run at a faster pace for one minute and follow it with two minutes of a slow jog. The fast run will shoot your heart rate up, while the slower jog will allow your heart rate to come back down slightly. Alternating speeds keeps your heart rate challenged which helps to burn more calories. Cardio intervals can also be done without any machines. For example, try intervals using a jump rope. Jump rope at a steady pace for 30 seconds, then speed jump for 15 seconds. Continue alternating these intervals five to 10 times for an intense interval workout.
Swim Like a Fish
Swimming does more than just burn calories, it also tones your muscles. Swimming involves your entire body, using your arms and legs to propel you through the water. Since your body is weightless in water, swimming is also a stress-free workout for your joints. This makes swimming an exercise that you can do for longer than other cardio workouts such as running, because your body won't suffer from constant pounding. In order to get the most out of your swimming workout, switch up the strokes every lap. Alternate between a faster stroke such as freestyle and a slower stroke such as the back stroke. This will ensures you're utilizing every muscle in your body, and your heart rate will also increase with the change of pace and stroke.
Swing a Kettlebell
Kettlebells are a canon ball like weight that delivers a resistance and cardio workout in one exercise. Most kettlebell exercises are basic but they require you to engage your entire body to perform them properly, which means you will be working harder than a typical strength training workout. Exercises like the swing and snatch raise your heart rate significantly, torching calories during the workout. Kettlebells not only deliver strength benefits, but also help to improve aerobic capacity, balance and core strength.
Crank Up the Resistance
Most cardio machines such as the treadmill, elliptical and stationary bike allow you to alter the resistance of the machine. By choosing a higher resistance, you are making your workout harder. Changing the resistance on a treadmill makes it so that you are running uphill, while increasing resistance on the pedals of an elliptical and stationary bike makes them harder to push. Small changes in the resistance makes your body work harder, which means that you will burn more calories, working your way to a lean body.