High-Intensity Interval Training (HIIT) frequently gets press for its more intense style of cardio, as well as its ability to help burn fat. However, the residual benefits of HIIT are often overlooked by those beginning interval training.
I personally love interval training. I've done the 60-minute steady-paced cardio sessions in the past, but when I'm working out, I like to be mentally engaged. Often I would find myself zoning out in the middle of an hour-long cardiopalooza, which never happens to me now during HIIT. Interval training challenges a personally physically and mentally.
During an intense interval session, the workout requires you to push your body to its physical limits. Whether running, swimming, rowing, or any other physical activity to which interval training can be applied, both your mind and body may tell you that you've pushed too far. You're lungs will ignite, and the thought of slowing down becomes more tempting with every gasp. But this is where character is built, and you develop as a person.
When a workout gets tough, it's easy to quit. But unless you've injured yourself, it's best to press on and really unlock your body's potential. In the toughest moments, these are where you'll have to convince yourself to not give up. These are the moments in which you will lay the foundation for being able to drag yourself to the gym when your muscles are sore or you're burned out from work. During the tougher moments of interval training, this is where you'll not only be leaving your excess body fat behind, but will be running towards a more resilient you.
Now, enough with the inspirational talk, let's discuss more empirically-based benefits of interval training.
How A Study on Rowing Illustrates the Residual Benefits of HIIT
James W. Fell, senior lecturer and coordinator of the Exercise Science Program at the University of Tasmania, co-authored a study in 2009 which investigated the effects of HIIT training, specifically on well-trained rowers. Fell's study used an equal split of five male and five female, all of whom were qualified to be "well-trained." The researchers of the study randomly placed the ten athletes into one of two groups. Over a period of four weeks, the first group used HIIT as its method of training, while the second group continued using a more standard form of rowing training.
By the end of the four-week period, research showed that both groups improved in performance from their initial testing. However, the HIIT training showed to improve performance much more significantly than the standard training. How significantly? The HIIT group decreased their 2000m time by roughly 8 seconds, while the standard rowers lowered their time by only 2 seconds.
Interval Training Improves Endurance Performance
Maximum oxygen consumption (Vo2 max) essentially measures how much oxygen a person's body can consume while performing work at its maximum level. While HIIT is an anaerobic exercise, it helps to develop a person's maximum oxygen consumption level, which can aid in aerobic exercise and endurance activities. To put this simply, consider the rowers in the study. Those who trained with HIIT logged a quicker time than those who used standard training, because their higher Vo2 max allowed them to maintain a faster rowing pace than their counterparts.
Another by-product of improving Vo2 max is that a person becomes less tired after exercising. Usually after an intense cardiovascular exercise, an individual has trouble catching his or her breath. But through interval training, a person's Vo2 max increases, and thus the time it takes to recover decreases.
Interval Training Improves Fast-Twitch Muscles
Muscles are separated into two different types: Type I and Type II. Type I or slow-twitch muscles are associated more with aerobic exercises mainly because those are the muscles which can do more work before fatigue sets in. People who run marathons use their slow-twitch muscles much more than their fast-twitch muscles.
On the reverse are fast-twitch muscles. As you've probably guessed by now, fast-twitch muscles are the muscles used most during sprinting and interval training. A person's power and speed are directly related to their fast-twitch muscles, and through proper exercise, an individual can become both stronger and faster. The downside to fast-twitch muscles is that they're only meant to be used for very brief times, and can fatigue very easily. Our HIIT rowers from the study showed a marked improvement in their rowing power compared to their traditional training peers.
Final Conclusion
I understand that most people will use interval training as solely a method of burning fat and losing weight. But by beginning interval training, these individuals are transforming themselves into much more well-rounded athletes. Both their aerobic and anaerobic capacities will improve, and what used to physically drain their body will no longer challenge them. Whether a person intentionally sets out to achieve the residual benefits or not, he or she can't help but feel the full effects provided by interval training.
