Fat metabolism was significantly higher in those who did any type of exercise for four weeks or more, with HIIT providing the most fat-burning bang for the buck.
After 12 weeks of HIIT, each minute of physical activity was equivalent to an additional 0.13 grams of fat burned, the researchers explained. For someone who engages in 150 minutes of physical activity per week, this could lead to approximately 10kg of additional fat burning in a decade.
Pedišić explained that the possible reason HIIT is “superior” in this regard is its “greater potential… to increase mitochondrial respiratory function and mitochondrial protein synthesis, factors that are associated with better fat oxidation.”
Dr. Filippe Oliveira, a professor in the School of Clinical Sciences at Monash University, said that although the increase in fat metabolism was less, HIIT had the added benefit of taking about half the time.
“It was also interesting to note that, in this study, although interval training improves fat oxidation in both ‘normal’ weight and overweight and obese individuals, greater improvements were seen in the latter,” said Oliveira, who was not involved. in the study. research.
Although this study did not explore the mechanisms, Pedišić said that previous studies have suggested that greater fat burning during exercise among people with obesity may be due to higher concentrations of non-esterified fatty acids at rest: an important metabolic fuel – and higher levels of intramuscular triglycerides.
Charging
HIIT is very different for someone who is unfit or overweight compared to someone who is fit or a healthy weight, so how do we define it?
“HIIT is a type of training that involves repeated bouts of high-intensity exertion followed by varied recovery times,” Oliveira said. “The ‘intense exercise’ period can last anywhere from a few seconds to a few minutes, and is typically performed at 80 to 95 percent of a person’s estimated maximum heart rate (the maximum number of times your heart will beat in a minute without trying too hard).
Pedišić added that inactive people consult a health professional before starting a HIIT program: “There are many different types of HIIT workouts to choose from, and an appropriate one can be found even for people who never or rarely exercise.”
With around two billion overweight adults around the world and billions more trying to keep their weight within a healthy range, Pedišić said the research is yet another reason to add a little HIIT to your day.
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