Our bodies have memories, they remember the stress you put on them, when you train them. Eventually they get use to it, they get comfortable, this is when the exercise ceases to be effective, and it is time to make new memories. Change from the bike to the elliptical, or go from a treadmill to running outside. Do not get stuck in the same routine, doing the same things over and over again, it is not helping you reach your goal!
Cardio is a double edged sword, get to little and it does not do anything for you, get too much and it will have negative side effects.The only real reason to train your cardio for more then 30 minutes is if you are training for a marathon, or if you REALLY enjoy doing cardio. If you have poor nutrition, or you have not had enough water then doing too much cardio will results in your body having to release stress hormones. This will cause your body to store fat, and your body will turn to your muscles for energy, rather then burning off the stored fat in your body.
Are you working hard enough? When it comes to losing body fat, and getting all the benefits of cardio it all comes down to the intensity of the exercise, not the length.The reason for this is because when you workout at an easy pace your bodies metabolism will return to normal almost right after. When you train at a higher intensity your metabolism will continue to be sped up several hours once you cease exercising. So if you count the calories burnt during the cardio session and you may see that you have burnt 300 calories, that sounds pretty good, however at a high intensity you may burn that same 300 calories, and continue to burn more calories during the rest of the day!
You want to make sure that your workouts are challenging, however they should be challenging in terms of your level of fitness. Just like every new years, the gyms become packed with the New Year’s resolution crowd. Theses people always say that they are going to get back into the routine, well what stops them? They end up going to hard, and either end up wearing themselves out to the point where they do not enjoy it, or even worse they hurt themselves because there bodies are not use to the amount of stress they are putting on it.
This last one is the most important. If you have trained correctly then your body will need time to health and repair itself from the stress that you put on it. If you are doing intense cardio you and you do not give your body a days rest then it will not be able to perform as well the next time. This can cause injury. Going at a low intensity on your day off can be beneficial, because it can help the recovery process. Always make sure to stretch to maximize your bodies ability to recover.