Aerobic exercise (also called cardio) is exercise that generally involves large muscle group and is per formed for a sustained amount of time. Aerobic exercise generally increases your heart rate and overtime strengthens your heart and lungs. Fortunately many aerobic exercises are more fun than hard work. Getting cardiovascularly fit does not mean long boring sessions at a gym, it means finding activities that are fun and challenging and most important of all, that you will do consistently.

The recommendations for cardiovascular exercise from the USDA are to:
Do moderately intense cardio 30 minutes a day, five days a week
Or
Do vigorously intense cardio 20 minutes a day, 3 days a week

As you can see, the more intense the workout the fewer times a week one would need to exercise. 

It can be simple to get more activity in every day. 
• Three 10 minutes increments can add up to thirty minutes of activity so spread your exercise out if it seems daunting. 
• Take the stairs every time
• Move more on the weekends; you may be tempted to get in a few extra hours of sleep on the weekends but try moving instead!
• Try a new class at the gym
• Get a workout buddy so you can’t skip!