The body is an interesting piece of equipment. Have you ever noticed how a work out regimen starts out challenging, but becomes progressively easier over time? You feel less winded, your are not as sore afterwards, you breeze through it. If one exercises the same way for long enough that particular exercise will become ineffective.
The phenomenon is adaptation. Our bodies adapt and build up a "tolerance" to the activity that is introduced over and over. This is a good thing and a bad thing. The human body was created to adapt for survival so that strenuous activity, stress and strain on the body would not kill the body, but instead the body would adjust making the necessary changes to keep living. This is great. The not so great part is that because of this fact the human body cannot continue to repeat the same activity and expect the same result over time. The body will get used to the load, adjust and after a while you will be wasting more time than producing positive results.
The bodies ability to build up a tolerance to exercise is often the reason why we plateau and slow down or stop losing weight when at the beginning of a regimen the weight just fell off.
One way to ensure that the body will not experience plateau and exercise tolerance is to circuit train or change up your regimen often. This way you confuse the body and don't give it time to adapt to what you are doing to it (because what you are doing to it is never the same).
But what if you really love a certain routine or exercise form like Zumba or Kick Boxing? Exercise is just as much about enjoyment and finding a routine you can stick to as it is about the technical aspects. So you don't want to try P90X or Cross Fit because it's just not for you or you don't like it? The fore mentioned exercise forms are known to blast fat and build muscle and the main reason is because they cause "muscle confusion" and do not allow the body to get used to a routine. The theory is if you can keep the body guessing, you can trick it into losing weight and getting in shape. However, you just may not want to do it even it gets results.
There is another way to boost your metabolism without really shaking up your work out routine. Add ankle weights and wrist weights to you every day routine. The extra weight adds intensity and resistance and will cause you to burn more fat and calories and build more muscle.
If you really want to add to your caloric burn and boost your metabolism, try wearing the weights to do house work or run errands. As discussed earlier, the body will always adjust for the load, but using them strategicly and at different times a day can keep the body guessing.
As the body gets used to the weight you may even want to add heavier weights to keep the process going. You will begin to feel more toned, you may see faster results and you will definitely get stronger.