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• Posted August 14, 2023

What's Your Exercise 'Fat-Burning Zone'?

A more personalized approach to exercise may be necessary, claims a new study that found fat burning varied widely between individuals.

Even worse, this rate often does not align with the “fat-burning zone” on commercial exercise machines, the researchers added.

Clinical exercise testing, a diagnostic procedure to measure a person's physiological response to exercise, may be a more useful tool, the study authors said.

“People with a goal of weight or fat loss may be interested in exercising at the intensity which allows for the maximal rate of fat burning. Most commercial exercise machines offer a ‘fat-burning zone' option, depending upon age, sex and heart rate,” said lead study author Hannah Kittrell. She is a PhD candidate at Icahn Mount Sinai in the Augmented Intelligence in Medicine and Science laboratory, in New York City.

“However, the typically recommended fat-burning zone has not been validated, thus individuals may be exercising at intensities that are not aligned with their personalized weight-loss goals,” Kittrell said in a Mount Sinai news release.

The researchers noted that the term FATmax is sometimes used to represent the exercise intensity and associated heart rate at the time when the body reaches its highest fat-burning rate during aerobic exercise. Fat is a significant fuel source at this point.

For the study, the investigators compared heart rate at FATmax, as measured during a clinical exercise test, to the predicted heart rate at percentages of maximal effort within the typically recommended “fat-burning zone.”

Working with a sample of 26 people, the team found there was poor agreement between measured and predicted heart rate. The mean difference was 23 beats per minute between the two measures. This suggests that general recommendations for a “fat-burning zone” may not be accurate.

The findings were published online recently in the journal Nutrition, Metabolism and Cardiovascular Diseases.

The researchers now plan to study whether people who receive a more personalized exercise prescription have more weight loss and fat loss, as well as whether they improve in health risk areas such as type 2 diabetes, obesity and heart disease.

“We hope that this work will inspire more individuals and trainers to utilize clinical exercise testing to prescribe personalized exercise routines tailored to fat loss. It also emphasizes the role that data-driven approaches can have toward precision exercise,” said senior study author Dr. Girish Nadkarni, a professor of medicine at Icahn Mount Sinai and director of The Charles Bronfman Institute for Personalized Medicine.

More information

Here's more on what types of exercises can help you lose weight.

SOURCE: Mount Sinai Health System, news release, Aug. 10, 2023