The evidence is mounting for high-intensity interval training on a number of fronts.

On September 29, 2015, ABC Catalyst ran a segment titled Fit in 6 minutes a week, which explored the benefits of high-intensity interval training. The regimen they advocated for was high intensity exercise (uphill running, cycling with resistance, anything that involves maximum exertion) for 30 seconds at a time, with approximately 4.5minutes rest between intervals. The offered the best explanation so far for why we should be pursuing high-intensity interval training; mitochondrial selection. The mitochondria are the powerhouses of our cells. Exercises that place extreme demands on the mitochondria effectively promote survival of more efficient mitochondria and “weed out the duds”.

A common reason given for not exercising is time constraints,i and long term adherence to exercise programs is often less than 50% at 6 months.ii HIIT allows equal or improved outcomes for markedly less time investment and has the potential to be associated with higher rates of adherence iii . In one study, similar changes were seen over a 6 week period in both HIIT subjects and CME subjects, although HIIT subjects performed only 20% of the exercise duration performed by the CME group v, making it an extremely efficient intervention.

Next Step Health will endeavour to make high-intensity interval training available as an option for clients to explore when attending our classes, particularly those classes with a cardio component. Our circuit class structure allows for some flexibility in this regard, so the 30-second intervals can be carried out by willing participants when the circuit changeover occurs. Clients with cardiovascular or pulmonary disease should seek guidance from a specialist (cardiologist or respiratory physician) prior to commencing high-intensity interval training.

Please take the time to watch the video before you decide if you wish to give it a go.


i. Trost SG, Owen N, Bauman AE, Sallis JF, Brown W. Correlates of adults’ participation in physical activity: review and update. Med Sci Sports Exerc 2002;34:1996–2001. Search PubMed


ii Thurston M, Green K. Adherence to exercise in later life: how can exercise on prescription programmes be made more effective? Health Promot Int 2004;19:379–87. Search PubMed


iii King AC, Haskell WL, Young DR, Oka RK, Stefanick ML. Long-term effects of varying intensities and formats of physical activity on participation rates, fitness, and lipoproteins in men and women aged 50 to 65 years. Circulation 1995;91:2596–604. Search PubMed


iv Bartlett JD, Close GL, MacLaren DP, Gregson W, Drust B, Morton JP. High-intensity interval running is perceived to be more enjoyable than moderate-intensity continuous exercise: implications for exercise adherence. J Sports Sci 2011;29:547–53. Search PubMed


v Gibala MJ, Little JP, van Essen M, et al. Short-term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance. J Physiol 2006;575(Pt 3):901–11. Search PubMed