Interval training is a form of cardiovascular workout which is characterized by periods of higher intensity exercise followed by periods of lower intensity for recovery. In contrast, regular cardiovascular workouts consist of maintaining only one intensity of exercise for a prolonged period. Research has shown that interval training has considerable advantages over conventional cardiovascular training.

Advantages:

-Larger increase in VO₂max

-Greater improvements in lactate threshold

-Larger increase anaerobic capacity

-Greater increase resting metabolic rate

-Larger improvements in body composition

These effects even occur when total training time or energy consumption is less than in conventional cardiovascular training, provided the intensity of the interval training is high enough.  These effects can be explained by the higher intensity of the intervals compared with regular cardiovascular training. The higher intensity is a stronger stimulus for the body to adapt to the demands of the training. A disadvantage of interval training is that to attain the higher intensity during training a stronger motivation is needed from the athlete to sustain the training and it takes a little more planning and preparation for choosing the right intensities and durations of interval periods.

Applying interval training:

Intervaltraining can be performed on virtually all cardiomachines (e.g. treadmill, crosstrainer, stairmaster, stepmachine, rowmacine etc.) present in a normal fitness center. Outside the fitness center it can be performed during running, cycling or swimming. There are numerous variations of interval training which can be applief, depending on the training goal, although research has yet to present a complete overview of all effects. Usually the durations of the high intensity phase and recovery phase are varied, by as much as a few minutes to as little as a few seconds for the highest intensity intervals.

Because the training intensity is usually rather high, normally it is not recommended to apply this to beginners or people who are very unfit. Only when people have a certain basis to build from, e.g. they can perform normal cardiovascular training at around 70% maximal heart rate or under the breathing threshhold for around 10 minutes, it is advisable to apply this form of training.

A few guidelines to help design an interval workout:

-Higher intensity yields greater results in VO₂max, resting metabolic rate and body composition

-Shorter recovery interval yield stronger effects on lactate threshold.

References:

-Baechle, T.R., Earle, W.R. (2008). Aerobic Endurance Exercise Training. Essentials of Strength Training and Conditioning. Third Edition. USA. Human Kinetics.

-Tabata I, Nishimura K, Kouzaki M, Hirai Y, Ogita F, Miyachi M, Yamamoto K. Effects of moderate intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max. Medicine & Science in Sports & Exercise, 1996, 28, 10, 1327-1330.

-Wilmore, J.H., Costill, D.L., Kenney, W.L. (2008). Principles of exercise training. Physiology of Sport and Exercise Fourth Edition. USA Human Kinetics.

-Yoshioka M, et al. Impact of high-intensity exercise on energy expenditure, lipid oxidation and body fatness. International Journal of Obesity 2001, 25, 332-339.