Interval training is a fantastic, very efficient way of training to achieve cardiovascular fitness as well as improvements in speed and strength.
Interval training refers to a method whereby you work very hard for a short period followed by a short period of rest and this is repeated over and over. This type of training is very efficient in producing results as it allows you to train at a higher intensity on average over the whole session than would otherwise be possible.
During the phase where you are working very hard, the aim is to work to a level which is only sustainable for a short period. In doing this, you force your body to work harder than it usually would and your heart rate would increase to be higher level than achievable in a longer sustained effort.
The rest phase is designed to allow you to rest just long enough to allow you to keep going through the entire session, but not long enough to allow your heart rate to drop too much. Essentially the end result is a full session where your average heart rate is kept above what you would be able to keep it at if you were trying to train at the same intensity the whole time and therefore creating a greater training effect. By maintaining a higher average heart rate, your body is forced to adapt to a greater extent and this leads to greater improvements in cardio fitness.
Interval training has been shown to burn a higher number of calories than endurance training and also increases the body’s anaerobic threshold. This means that your body can withstand the accumulation of lactic acid for longer and to a higher degree.
Lactic acid is the waste product of the body trying to produce energy in the muscles without oxygen. This occurs when a quick, higher intensity effort or a quick burst of energy from 1-3 minutes is required. When the body is working extremely hard, so hard in fact that the muscles demand more oxygen than it can take in, the production of lactic acid essentially slows the body’s capacity for work in an effort to protect the body and allow more oxygen in.
However this process is a bit counterproductive to someone who is trying to gain increases in their fitness but this is where interval training can be beneficial. After a short period of intense effort, the body naturally starts slowing itself down through the build up of lactic acid (that’s the heavy, burning feeling you feel in your muscles) and that’s the perfect time to have a short rest to allow the lactic acid and other metabolites that have built up to be cleared, ready for the next effort. Repeated over and over again, your body learns to deal with the lactic acid more efficiently allowing you to train at a higher level for longer.
An example of an interval session might be something such as this:
Warmup for 10 minutes at a gentle pace.
Hard effort at 75-85% of your maximum for 3 minutes then rest for 1 minute.Repeat this 4-8 times depending on your ability and goals.
Warm down for 10 minutes at a gentle pace.Ensure you stretch at the end.
Good luck with your training and enjoy your intervals!