If your goal is to build up aerobic endurance, but dislike long cardio sessions, then Long Interval Training might be for you. This method aims to develop aerobic endurance through relatively short exercise intervals, while challenging your VO2max capacity. It should be performed at an intensity of about 80-90% of your VO2max, or 88%-95% of your MHR, maximum heart rate.
You should perform 1 series of exercise, with 2-5 repetitions per series. Each repetition should be sustained for 5-15min, excluding your warm up and cool down. Your perceived effort level for this type of training should be in the 5-7 range. Take some rest in between your repetitions, calculate 30-50% of your time of exertion (i.e.: if your repetition lasts 10min, take 3-5min rest). Due to the increased demands this training method places on your body, 36-48hrs will be required to recover properly from this.
Next week, Medium Interval Training.