High-intensity interval training (HIIT) is an approach that mimics the physical activity pattern of hunter-gatherers. Research has shown that HIIT leads to equal or superior gains in cardiovascular health and fitness when compared to traditional cardio, but takes only a fraction of the time.
How did hunter-gatherers move? They didn’t have access to gyms. Yet they were extremely fit and almost entirely free of most modern chronic diseases. They performed low-intensity movements like walking, gathering foods, or manual labor daily. From time to time, the exigencies of life would require a burst of intense activity—such as going on a hunt, running from a predator, or fighting for survival.
In contrast to traditional cardio, HIIT involves performing movements at very high intensity for short periods of time—usually between thirty seconds and two minutes. Studies have been done comparing HIIT to low-intensity, steady-state exercise, and HIIT has been shown to be superior in nearly every meaningful marker.
In one study, one group was assigned to traditional cardio workouts, while the other was assigned to HIIT. After fifteen weeks, the researchers found that both exercise groups demonstrated a significant improvement in fitness. However, only the HIIT group had a significant reduction in body weight, fat mass, abdominal fat, and fasting plasma insulin levels. Leptin levels were also significantly lower in the HIIT group. Other studies have shown that high-intensity training creates uniquely favorable metabolic and structural changes in muscle.
High-intensity interval training also helps you burn calories for up to forty-eight hours after your workout is over by eliciting a powerful physiological effect known as EPOC or excess post-exercise oxygen consumption. EPOC describes your body’s capacity to utilize oxygen and burn calories following a high intensity activity. HIIT produces greater EPOC responses than traditional cardio. During the forty-eight hours after your workout, your body continues to utilize oxygen at a higher rate and burn calories by metabolizing and breaking down fat.
In the next post I’ll review exactly how to do a HIIT workout–safely, without risking injuries…