H.I.I.T or high intensity interval training workouts, are very high intensity workouts consisting of heavy workloads paired with rest periods. Many studies have shown that these workouts, while taking less time than a moderate paced workout, can drastically improve cardiovascular capacity- especially when compared to steady pace cardio workouts lasting 15-30 minutes. These workouts consist of a short warm up period followed by a short high exertion exercise, followed by a short rest period, then this is repeated for the desired number of cycles and followed by a short cool down. These workouts generally last no more than 20 minutes- much shorter than the standard 30 minute moderate pace workout that is often promoted for building endurance. There are several different types of this training and the exercise can be anything you can perform at a very high intensity for a short time, including but not limited to: running, swimming, biking, rowing, and stair climbing.
There are several benefits to this type of training, among them: increased fat loss, increased metabolism even AFTER exercise, VO2max increases, and a stronger cardiovascular system. High intensity interval training is far superior to most other types of cardiovascular training.
The tabata protocol was a popular study from 1996. The participants engaged in workouts consisting of a 5 minute warm up, 20 seconds of very high intensity exercise (at max effort), followed by 10 seconds of rest, then repeated for 4 minutes or 8 cycles total, they ended the workouts with a light 2 minute cool down. The study compared the results of the group who exercised 4 days per week with the tabata protocol, to a group who did steady pace- 30 minute- training four days per week. At the end of the study the results were astounding, not only were the results similar but the group who did tabatas had a slightly higher increase in V02 max, and they also gained anaerobic benefits that the steady pace group did not receive from any of their exercise.
You can try the tabata protocol for yourself if you are interested: 5 minute warm up, 20 second max effort, 10 second rest (repeat the max effort and rest cycle 8 times), and then cool down for 2 minutes, or you can try your own interval training method. Many people use different exercises to engage in interval training, weight training, running, swimming, or calisthenics can all be good choices for elevating your heart rate and allowing yourself to gain the benefits of interval training. In order to interval training to be effective you must be willing to push yourself hard during your work periods and elevate your heart rate to your target rate.
If you want to try a new way to push your health and fitness to the next level give interval training a try.