“High intensity interval training can produce similar if not greater improvements in cardiorespiratory fitness, an independent protective factor against premature death, and some health-related parameters compared to conventional, moderate intensity continuous training.

“High intensity interval training takes substantially less time to complete and this enhances its potential in public health promotion given that lack of time is one of the barriers to long-term adherence to physical activity and exercise training.”

High intensity interval training describes exercise bouts of 10 seconds to 4 minutes with ‘all-out’ maximal effort or intensities of 85–95% of maximum heart rate interspersed by periods of low activity or rest (30 seconds to 4 minutes).

“Despite the accumulated evidence, very little improvement has been made in terms of high intensity interval training implementation in real life settings…”

G.P. Nassis
High-intensity interval training: how much pain to get a gain?
British Journal Of Sports Medicine — Volume 51 #6 — March 2017

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TheETG exercise program —– http://theetgtrackclub.com/documents/TheETGexerciseprogram.pdf