Because it is a quick and effective way to improve health, high intensity interval training has grown in popularity. This is especially important as countries around the world emerge from coronavirus lockdowns and seek quick and easy ways to exercise again.
Researchers have recently been investigating whether shorter variations of HIIT, involving as little as 4-min of high-intensity exercise per session (excluding a warm-up and cool-down), can also improve health.
A new review paper published in The Journal of Physiology brings together a decade of research on the topic of this so-called low-volume high HIIT for health.
The current World Health Organization (WHO) physical activity guidelines (150-300 minutes of moderate activity per week or 75-100 minutes of vigorous activity per week) may be unattainable for a large portion of the population due to family or work obligations.
The rising rates of physical inactivity among adults in high-income countries lend credence to this hypothesis.
The findings of this study show that low-volume HIIT (typically less than 20 minutes total exercise time – including warm up and cool down) produces comparable results to interventions meeting current guidelines despite taking significantly less time.
So, what exactly is low-volume HIIT? Because HIIT involves active and recovery periods, the researchers defined low-volume HIIT as interventions that included less than 15 minutes of high-intensity exercise per session (not including recovery periods).
This review builds on the authors’ recent study published in Diabetes Care, which found that as little as four minutes of HIIT three times a week for 12 weeks significantly improved blood sugar levels, liver fat, and cardiorespiratory fitness in adults with type 2 diabetes. They also demonstrated that these improvements were comparable to a 45-minute moderate-intensity aerobic exercise intervention (2).
Aside from its impact on metabolic health, the new study found that low-volume HIIT can improve heart function and arterial health.
While the overwhelming majority of available evidence indicates that low-volume HIIT is a safe way to exercise, including in populations with metabolic and heart problems, individuals should always consult with their health care professional to determine their individual suitability for such programs.
This study was carried out by compiling and critically evaluating over a decade’s worth of research on the subject.
Further research should be conducted to determine whether low-volume HIIT is long-term sustainable and whether combining low-volume HIIT with other training interventions, such as resistance training, can improve health outcomes.
Many of the participants in the study published in Diabetes Care expressed surprise at how short the training was and how good they felt afterward.
Dr. Angelo Sabag, the study’s corresponding author, stated:
“While WHO guidelines may serve their purpose at the population level, individualised and tailored low-volume HIIT interventions delivered by appropriately trained exercise professionals may be more effective at the individual level, particularly for time-poor individuals.”
This research is especially important now, as people seek new and exciting ways to engage in regular exercise after a year of decreased physical activity due to the pandemic.”