Most people would think that High Intensity Interval Training could be risky for people with coronary artery disease. There is now evidence to say that this is not the case at all.
A Canadian study published this year designed a 12 week exercise training study with 22 subjects who had documented coronary artery disease. Half of the subjects performed typical endurance based cycle training for 30-50 min at 60% of their measured limits. The other half of the subjects performed the high intensity interval training. This consisted of ten 1-min intervals of cycling at 90% of their measured limits, separated by 1-min intervals at 10% of their limit. Both groups completed the sessions twice per week.
Cardiorespiratory fitness was measured before the programme began and at the end of the 12 weeks of exercise training. Both groups improved by a significant 24 percent even though the High Intensity Interval group completed 80% less volume than the Endurance group. There were no adverse events throughout. This improvement represents a 12% improvement in survival as previous research has shown that as fitness increases survival also increases.
This evidence supports doing either type of exercise training. Some will prefer the interval training and some the endurance training. However, there is growing support that exercise intensity may be more important than exercise duration in terms of cardiovascular health. More on this in future articles.
Currie, K. D.,et al. Low-Volume, High-Intensity Interval Training in Patients with CAD. Med. Sci. Sports Exerc., Vol. 45, No. 8, pp. 1436-1442, 2013.