First of all, interval training builds lung capacity. I have already talked about in my post The Power of the Breath. Lung capacity has been linked with longevity, energy and vigour, and well being. Having a decent lung capacity is also a must for fitness. So if you want to have better quality of life later on, start exercising now.
Second, interval training, like sprints, will build new muscle fibres. Muscle mass diminishes with age. Muscle fibres are dying and new ones are not growing fast enough to make up for the loss. One way to keep up the muscle size and mass is to do resistance training. However, this only accomplishes the bulking up of existing fibres. It would be good to grow some new ones, but it’s getting more and more difficult with age. One way around this problem is to have existing fibre cells split lengthwise into 2 (hyperplasia) . This can be achieved with very explosive effort. Sprinting, box jumping, explosive power lifting, sprint swimming etc are good examples of the specific effort required. You can wrap them up into your interval routine quite easily.
Thirdly, this type of exercise will save you time. You can do 6 one minute sprints with 4 minute rests in between and still finish your workout in under half hour. Sometimes I do sprints for about 15-20 seconds, depending on the intensity. And you will get fit. I’ve hit my hear rate up to 220 doing it this way. My resting rate is below 60. I don’t think it’s too bad for 40-something. Compare that with one hour aerobics, circuit class or even longer for long distance running. These days when everyone is working longer and longer any minute you save is a bonus. If I have to spend 30 minutes in the gym, then might as well make it quality time. And interval training gives me maximum bang for a buck.
Furthermore, I don’t think that a prolonged elevated heart rate is a good thing, like in traditional cardio workouts or marathon running. It puts a lot of strain on the heart and, like mentioned in my The Power of the Breath post, makes your body more efficient at storing energy and oxygen consequently, reducing the fitness, lung capacity and promoting fat storage.
And lastly, leading from the third benefit, it is less boring. Some people like to run for 2 hours at a time, they say it is relaxing them, or they use that time to meditate. That’s fine, each to their own. Personally, I find repetition a bit boring. I used to run 10km but did not do it often because it bored me to tears. That’s also the reason why after spending 2 years of doing weight training 6 times a week for 1.5 hours each session, I could not even look at another gym for the following 15 years. Now, I keep the routine short and sweet and more interesting by varying it and mixing weights with interval training
As a final word of caution, please see your doctor before embarking on any vigorous exercise routine, and stay in shape.