What to do when your cardiovascular exercise isn't working anymore!

Tips to get you back on track! 
We've been taught that performing cardiovascular exercise for 20 to 30 minutes at a target heart rate of 60 to 80 percent is the best way to lose your excess fat. Yes, it can be. But, what do you do when you have hit that weight loss plateau and your cardio workout isn't working any more? 

One of the methods I've used to change things up is interval training. I would have to describe Interval training as integrating higher-intensity exercise with lower intensity. This will help spark and speed up your metabolism. Intervals can be applied to any form of cardiovascular exercise. It has been a widely used technique for training athletes since the '50s, but this concept has grown into mainstream fitness in the last 10 years. 
The beauty of interval training is that you don't have to work out for long periods. Unless you're training for a competitive event, anything longer than 25 to 35 minutes is not required, and that includes warm up and cool down. 

Here is an example of interval training using a treadmill: 
Begin with a warm up of five minutes at level 3 intensity (3 mph): 
A. On the sixth minute, increase to 4 mph (light jog)
B. On the seventh minute, increase to 5 mph
C. On the eighth minute, increase to level 6.5 or 7 mph
D. For the next two minutes, (minutes nine and ten) return to 3 mph
E. Repeat A-D two additional times, but increase the level of intensity one mile per hour on each phase.
F. Cool down for five minutes at 3 mph 
The total workout time including warm up and cool downs is 25 minutes. A-D above represent one cycle. In this example, you perform three cycles of higher-intensity cardio. If you're at a more advanced fitness level, then you'll need to adjust the speeds and times accordingly to make sure the intensity is somewhat demanding at the higher levels.
Hope this helps.
Have an Amazing Day