Which type of aerobic exercise is superior for improving cardiorespiratory fitness? High-intensity interval training (HIIT) or moderate-intensity continuous training (MICT)?
One piece of advice that is often heard is that high-intensity interval training (HIIT) is superior in improving cardiorespiratory fitness compared to moderate-intensity continuous training (MICT) and should therefore be given priority. Let's go see if this is the case!
WHAT ARE HIIT AND MICT
If you are not sure what high-intensity interval training and moderate-intensity continuous training are, you can read our article.
THE DATA
As we saw in a previous article, muscle mass is an important factor affecting cardiorespiratory health. However, since cardiac output and the difference in blood oxygen content between arterial blood and venous blood seem to play a more important role, aerobic exercise is necessary if we want substantial benefits.
A recent systematic review and meta-analysis attempted to compare the impact of moderate and high-intensity aerobic exercise on cardiorespiratory fitness in older adults, taking into account the volume of exercise performed.
Findings of the meta-analysis did not indicate strong evidence to suggest substantial differences in the effectiveness of moderate- and high-intensity aerobic exercise interventions in improving cardiorespiratory fitness as measured by V̇O2peak, taking into account the total volume of exercise completed.
When stratified by intensity, both moderate and high intensity exercise groups showed moderate to large positive effects on V̇O2peak.
One of the interesting findings was a negative correlation between session duration as well as intervention duration with improvement in V̇O2peak, suggesting that shorter session duration and overall intervention duration may lead to greater improvement in cardiorespiratory fitness in older adults.
Therefore, considering that these findings concern older people and interventions with an average duration of 20 weeks, these results probably lead us to the conclusion that the higher the intensity, the more fatiguing the intervention and therefore more breaks are needed, while the lower the intensity, the the necessity for breaks decreases.
In short, if we want to optimize our cardiorespiratory fitness, we need to engage mainly in continuous training of low to moderate intensity at a pace and duration that do not impose a strain on us, but without neglecting high intensity interval training, which should be performed in a much smaller proportion, so that the overall program can have as fewer breaks as possible.
-Suprastratum: The authority on health, fitness and nutrition
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