Many individuals who attend the gym on a regular basis do so to perform resistance training, cardiovascular activity or a combination of the two. Resistance training, dependant on your skill level, will often consist of a combination of both free and machine weights whilst cardiovascular activity will usually involve repetition movement over an extended period of time, whether this be on the treadmill, bike or rowing machine.

These are the norms which many individuals conform to on a daily basis and have done for weeks, months and years. As with everything in life, there is variety should you so desire – and the same can be said for your gym routine.

Recently, there has been a huge increase in the popularity and participation of an exercise alternative known as High Intensity Interval Training (or HIIT for short). This offers numerous benefits similar to those achieved through continuous endurance exercise, although their application couldn’t be more different. For those of you that were previously unaware, this article contemplates this new exercise craze and considers its reported benefits.

High Intensity Interval Training (HIIT)

Before getting too far ahead of ourselves, let us firstly consider a definition of HIIT: “HIIT generally refers to repeated sessions of relatively brief intermittent exercise, often performed with all out effort or at an intensity close to that which elicits your peak VO2 max” (Gibala and McGee. 2008).

Depending on the intensity you choose to work at, a single bout effort of HIIT can range from several seconds to several minutes, with multiple bursts of maximal effort separated briefly by complete rest or active recovery in the form of low intensity exercise.

From this description it almost sounds like resistance training in the form of weight lifting, however HIIT is commonly associated with your typical cardiovascular activities such as running, cycling and rowing (Rose and Leveritt. 2001).

The Benefits Of HIIT

Previous investigative research into the application and benefits of HIIT has revealed numerous remarkable benefits, which at first glance you wouldn’t think possible from a high intensity, interval related activity.

The first of those is your enhanced ability at performing aerobic activity. Burgomaster et al, (2008) demonstrated that after only six HIIT sessions, undertaken during a two week period, subjects on average were able to enhance their cycling times at a predetermined sub maximal effort from 26 to 51 minutes. Results from this investigation were strengthened by the control group which remained untrained during the two week period and recorded no significant alterations in their performance times.

So what happened during this short two week period to bring about such significant alterations in an individual’s aerobic performance ability? Consideration factors are likely to be a combination of both physiological such as cardiovascular, metabolic and neural as well as psychological such as mood, motivation and effort.

One significant finding from previous research has highlighted a significant increase in the muscular oxidative capacity of mitochondrial enzymes. These figure enhancements range from 15-35% after only two week duration (Gibala et al. 2006).

Further experimental research has also compared HIIT to continuous cardiovascular exercise performed at a sub maximal level. Subjects were randomly assigned to each of the groups and undertook six sessions during a two week period. During these trials the total training time for the HIIT group amounted to only 2.5 hours whilst the endurance group amassed in excess of 10.5 hours.

On cessation both groups were again examined, with each exhibiting similar mitochondrial adaptations as a result of their respective training regimes (Gibala et al. 2006). This demonstrates the potential efficiency of HIIT with minimal time input.

In addition to alterations in the muscular oxidative capacity of mitochondrial enzymes, HIIT is also responsible for bringing about significant adaptations in carbohydrate metabolism, glycogen utilisation and lactate production amongst other key physiological variables (Burgomaster et al. 2007).

Implementing High Intensity Interval Training

The key ingredient to a healthy lifestyle is to undertake regular exercise alongside a varied yet balanced diet. Many health guidelines advocate a minimal target of 30-60 minutes exercise on most days of the week to maintain stable health. Despite these public health announcements and clear health related benefits, many individuals fall significantly short of this target (Blair et al. 2004).

One of the main reasons given, whether you choose to accept it or not, for falling below these minimum exercise guidelines is a lack of time. With all this in mind, surely the promotion and utilisation of HIIT could solve both of these problems. Previous research has already demonstrated that you can achieve identical fitness outcomes in a quarter of the time simply by swapping continuous aerobic endurance for HIIT.

So why isn’t HIIT more readily utilised and more readily promoted? As with all exercise variations, HIIT does not escape without its fair share of criticism. The main sticking point often argued is that HIIT is unsafe and impractical for many individuals, as it requires you to be of good health and have a solid fitness foundation (Rognmo et al. 2004).

Final Word

Throughout this article and with the support of various scientific investigations, HIIT has been demonstrated to offer significant alterations to your aerobic capabilities through a combination of physiological and psychological adaptations.

These alterations have occurred in a relatively short space of time, with much of the research demonstrating adaptations within as little as six sessions and in the space of two weeks. Research has also demonstrated that the effects of HIIT can be achieved in as little as a quarter of the time as traditional, endurance related exercise.

If you consider yourself a sporting individual, who is fortunate enough to have good health and a solid fitness foundation then experimenting with HIIT has the potential to bring about both significant gains in your endurance related performances and general health.

Furthermore, if you’re an individual who loves to exercise but is constantly under time constraints through a combination of work, family and social pressures then again HIIT provides you with a suitable alternative to achieve your desired fitness outcomes in a condensed time frame.

Although further research is required to cement the support for HIIT, including types of training and optimal work and rest ratios, the potential efficiency and effectiveness of this new phenomenon is plain and simple for all to see.

Stay tuned for more information about specific HIIT training routines, optimal rest periods and much more on FashionBeans over the coming weeks.