What’s the best heart rate for burning fat? According to researchers at the Icahn School of Medicine at Mount Sinai, it depends on the individual. A recent study found that heart rates for fat burning vary widely. In fact, the ‘Fat-Burning Zone’ recommended by commercial exercise machines may not correspond to the individual variations among people.

The researchers wrote about their study and findings in the peer-reviewed journal Nutrition, Metabolism and Cardiovascular Disease (citation below).

Clinical Exercise Testing: A More Precise Approach

If your goal is to lose fat, Clinical Exercise Testing may be a more useful tool, the authors explained. Clinical Exercise Testing is a diagnostic procedure that measures our physiological response to exercise.

Lead author, Hannah Kittrell, MS, RD, CDN, a PhD candidate at Icahn Mount Sinai in the Augmented Intelligence in Medicine and Science laboratory, explained:

“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. 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.”

FATmax: Understanding Peak Fat-Burning Intensity

The term FATmax refers to the specific level of effort and heart rate during aerobic exercise where your body burns fat at its maximum rate. This peak fat-burning stage is often a focus for people who want to make their workouts as effective as possible for losing fat.

In the study, the scientists looked at the heart rate at FATmax during a special exercise test and compared it to the expected heart rate for the commonly suggested fat-burning zone. They did this with a group of 26 people and discovered that the actual and predicted heart rates didn’t match well, with an average difference of 23 beats per minute. It appears that the general recommendation for a fat-burning zone might not be as precise as we thought.

Graph showing how people burn fat differently

Created using an image from Hannah Kittrell, Mount Sinai Physiolab and AIMS Lab at Icahn Mount Sinai.

Towards Personalized Exercise Routines: Next Steps in Research

The researchers are now looking to find out whether people who follow a tailored exercise plan show better results in losing weight and fat. They will also be gathering and analyzing data on metabolic health markers that identify health risks such as heart disease, obesity, and type 2 diabetes.

Senior author, Girish Nadkarni, MD, MPH, Irene and Dr. Arthur M. Fishberg Professor of Medicine at Icahn Mount Sinai, Director of The Charles Bronfman Institute of Personalized Medicine, and System Chief, Division of Data-Driven and Digital Medicine, Department of Medicine, said:

“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.”

Kittrell, Hannah D., Fred J. DiMenna, Avigdor D. Arad, Wonsuk Oh, Ira Hofer, Ryan W. Walker, Ruth J.F. Loos, Jeanine B. Albu, and Girish N. Nadkarni. “Discrepancy between Predicted and Measured Exercise Intensity for Eliciting the Maximal Rate of Lipid Oxidation.” Nutrition, Metabolism and Cardiovascular Diseases, 2023, https://doi.org/10.1016/j.numecd.2023.07.014.