In the quest for effective fat loss through exercise, the “fat burning zone” touted by many commercial exercise machines may not hold the key for everyone, according to researchers from the Icahn School of Medicine at Mount Sinai. In a recent study published in Nutrition, Metabolism and Cardiovascular Disease, these scientists reveal that the optimal heart rate for fat burning is a highly individualized phenomenon, often diverging from the conventional fat burning zone.
Lead author Hannah Kittrell, a PhD candidate and Director of the Mount Sinai Physiolab, along with her team, propose that relying on clinical exercise testing could offer better insights into an individual’s ideal fat loss strategy. Kittrell explains, “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.”
Central to their investigation is the concept of FATmax, representing the exercise intensity and correlated heart rate at which the body reaches its highest rate of fat burning during aerobic activity. This level of intensity can be crucial for those aiming to optimize fat loss during their workouts.
The researchers conducted a study comparing heart rate at FATmax, as measured during a clinical exercise test, with predicted heart rate at various percentages of maximal effort within the conventional “fat-burning zone.” The results were revealing. Among 26 participants, there was a considerable discrepancy between measured and predicted heart rates, with an average difference of 23 beats per minute between the two metrics. This dissonance suggests that the general guidelines for the fat-burning zone may not provide accurate direction.
The team’s future endeavors encompass investigating whether personalized exercise prescriptions lead to greater weight and fat loss, alongside improvements in metabolic health markers linked to health risks such as type 2 diabetes, obesity, and heart disease.
Senior author Girish Nadkarni, MD, MPH, underscores the significance of the findings, stating,
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.
With the paper titled “Discrepancy between predicted and measured exercise intensity for eliciting the maximal rate of lipid oxidation,” the study underscores the importance of recognizing the intricate interplay between individual heart rates, fat burning, and the pursuit of a healthier lifestyle.
The research team includes experts like Fred J. DiMenna (The Mount Sinai Hospital), Avigdor D. Arad (Tel Aviv Medical Center), Wonsuk Oh (Icahn Mount Sinai), Ira Hofer (Icahn Mount Sinai), Ryan W. Walker (Icahn Mount Sinai), Ruth J.F. Loos (Icahn Mount Sinai & University of Copenhagen), and Jeanine B. Albu (Icahn Mount Sinai). As this rhythm of research continues, it is hoped that tailored exercise regimens can strike the right chord for those seeking to maximize their fat loss potential.