Metabolically healthy obesity is associated with the occurrence of autonomic dysfunction, which suggests that it can be, in fact, a transition stage to the development of metabolically unhealthy obesity.
Key Findings
Results
Individuals with metabolically healthy obesity (MHO) exhibited alterations in heart rate variability (HRV) compared to metabolically healthy eutrophic (MHE) individuals.
HRV was assessed as a measure of autonomic function in a cross-sectional study design.
Participants were stratified into three groups: metabolically healthy eutrophic (MHE), metabolically healthy obesity (MHO), and metabolically unhealthy obesity (MUO).
Recruitment was random, including individuals aged 18 years or older, with exclusions for those on sick leave, pregnant, or lactating.
Body mass index and International Diabetes Federation criteria for metabolic syndrome were used for group stratification.
Results
Individuals with metabolically healthy obesity showed alterations in the orthostatic hypotension test compared to metabolically healthy eutrophic individuals.
An orthostatic hypotension test was among the autonomic function assessments administered to all groups.
An orthostatic test was also performed as a separate measure of autonomic function.
Differences in orthostatic hypotension test results were observed between MHO and MHE groups.
These findings suggest impaired cardiovascular autonomic regulation in MHO individuals.
Results
Individuals with metabolically healthy obesity exhibited alterations in electrocardiographic parameters for ventricular repolarization compared to metabolically healthy eutrophic individuals.
Electrocardiography was used as one of the tools to evaluate autonomic function.
Ventricular repolarization parameters were specifically identified as altered in MHO compared to MHE.
Electrocardiographic changes in ventricular repolarization can reflect underlying autonomic nervous system dysfunction.
These ECG findings add to the evidence of subclinical cardiac autonomic alterations in metabolically healthy obesity.
Conclusions
Metabolically healthy obesity is associated with autonomic dysfunction, supporting the hypothesis that MHO represents a transition stage toward metabolically unhealthy obesity.
The study found autonomic alterations across multiple measurement modalities (HRV, orthostatic hypotension, ECG) in MHO individuals.
The authors concluded that MHO 'can be, in fact, a transition stage to the development of metabolically unhealthy obesity.'
Autonomic dysfunction was identified as 'an additional parameter' for evaluating the MHO phenotype.
The cross-sectional design limits causal inference, but the pattern of findings across multiple autonomic measures supports the transition hypothesis.
What This Means
This research suggests that people who are obese but appear metabolically 'healthy' — meaning they don't yet show signs of conditions like high blood pressure, high blood sugar, or abnormal cholesterol — still show measurable problems with how their nervous system controls the heart and circulation. The study compared three groups of adults: those with a healthy weight and no metabolic problems, those with obesity but no metabolic problems, and those with obesity and metabolic problems. Even the 'metabolically healthy' obese group showed differences in heart rate variability (a measure of how well the nervous system regulates the heart), abnormal responses to changes in posture, and irregular patterns on electrocardiograms related to how the heart's ventricles recover after each beat.
These findings matter because 'metabolically healthy obesity' has been debated as a concept — some researchers have argued it represents a genuinely benign form of obesity, while others have suspected it is merely an earlier stage before metabolic problems develop. This research suggests the latter may be true: even when standard metabolic markers look normal, the autonomic nervous system — which regulates heart rate, blood pressure, and many other automatic body functions — is already showing signs of dysfunction in obese individuals.
The study was cross-sectional, meaning it captured a snapshot in time rather than following people over years, so it cannot definitively prove that metabolically healthy obesity will progress to metabolically unhealthy obesity. However, the presence of autonomic dysfunction across multiple different tests in the healthy-obese group adds to growing evidence that this phenotype may not be as benign as once thought, and that autonomic testing could serve as an early warning tool for identifying health risks in people with obesity who otherwise appear metabolically normal.
Duque A, Araujo C, Nogueira I, Cerceau R, Lorenzo A, Huguenin G, et al.. (2026). Autonomic dysfunction in individuals with metabolically healthy obesity: a cross-sectional study.. Anais da Academia Brasileira de Ciencias. https://doi.org/10.1590/0001-3765202620250712