In our most recent book, Positively Smarter: Science and Strategies for Increasing Happiness, Achievement, and Well-being, we include chapters discussing science and strategies for reaping the benefits of exercise for the Body-Brain System. Once a good foundation of fitness is in place, interval training is one route to increasing fitness and for burning more calories.
In my training for half marathons, I usually run
longer distances at a steady heart rate of around 180 beats per minute minus my
age, which means I am jogging at a rate of between 128 and 130 beats per
minute. In addition, I do some days of interval training when I run harder for
30 seconds and then slower for around the same amount of time.
WebMD has a good article on this subject, with great information on how interval training can take your fitness to the next level.