Interval training has been around for a long time but recently has had a boost in support as one of the best methods to gain muscle and lose weight. The problem many people have with interval training is that it is HARD! You have to do sets of intense exercise followed by rest periods and to get the best results you need to keep count precisely on how long you work for and rest for. Compared to more steady paced exercises this can be difficult to achieve which is where having a beat comes in and the best workout music compliments the interval training style.
If you are not too familiar with interval training you may wonder at why it is so hard, and may not know why it is also so good! Interval training as has been mentioned is method of exercise that involves near maximum exertion training for a period of time followed by a rest period of much reduced intensity and repeating this pattern. So if you are running you might sprint for 10 seconds then jog for 20 seconds. It has been proven by many studies now that this method is superior to steady mid level intensity training for cardiovascular health and for muscle growth as well as it pushes and challenges your body but allows rest so you do not wear out quickly where a mid level exercise does not challenge the body enough and straight high intensity training wear you out too fast for lasting effect.
What music is important for is to keep time for these intervals and to keep motivated. The best workout music is hard to find among regular music to match your exact rhythms of exercise but anything with a good beat will allows you to keep count. The best workout music optimally would be music that matched high intensity music for your high intensity period followed by a more mellow tune for your rest periods but you will not find that in the top 40!
From this we can see the best workout music for interval training is not bought off the shelf but is made with this sort of exercise method in mind to produce the kind of results the fitness industry can deliver.