Hidden body fat linked to faster heart aging

The European Heart Journal published a study on how body fat distribution is associated with the "biological age" of the heart and blood vessels. A team from the MRC Laboratory of Medical Sciences (London) analyzed data from 21,241 participants in the UK Biobank: using MRI of the whole body and heart, they used AI to assess signs of cardiovascular aging, and then compared them with where exactly a person's fat is deposited - visceral (inside the abdomen, around the liver and intestines) or subcutaneous (including on the hips and buttocks). The conclusion is stark: the more visceral fat, the faster the heart "ages", and this is true even for outwardly slim and physically active people. At the same time, in women, a "pear-shaped" composition (more fat on the hips/buttocks) was associated with slower cardiac aging.

Background of the study

In cardiometabolic risk, fat distribution, not just total fat volume, is increasingly being considered. Visceral adipose tissue (intra-abdominal, perivascular, epicardial) is an active endocrine organ that increases inflammation and insulin resistance, whereas gluteofemoral (hip/buttock) subcutaneous fat is associated with better metabolic parameters and CV risk in many groups, probably due to “safe” fatty acid deposition and a different adipokine profile. These differences are supported by both epidemiology and studies taking into account individual fat depots.

Gender differences complete the picture. Women are more likely to have a “pear-shaped” body type and, with a comparable BMI, demonstrate a more favorable cardiometabolic profile; men have a predominance of central obesity with a more pronounced visceral component and worse outcomes. Modern reviews and population studies show that where fat is stored, not just “how much,” significantly affects risk, and this relationship differs markedly between men and women.

Classic anthropometric indices (BMI, waist circumference) poorly capture hidden depots. Therefore, MRI of the body is increasingly used for direct assessment of visceral and subcutaneous fat, as well as cardiac MRI and AI methods for calculating the “biological age of the heart” based on the morphology and movement of the chambers. Such “heart age” models based on UK Biobank data have already shown that MRI features of the heart are associated with aging and risk factors, and their integration with body composition allows us to study how exactly fat “accelerates” or “slows down” cardiovascular aging.

Against this background, a direct test is relevant: how does the distribution of fat by depots relate to changes characterizing cardiovascular aging, and whether these relationships differ in men and women. Large imaging cohorts with parallel MRI of the body and heart and deep learning tools (as in the UK Biobank) make it possible to answer these questions and clarify preventive goals - to reduce primarily visceral fat and take into account the gender context. This is precisely the task that the new study solves.

How it was studied - a brief overview of the methods

The researchers used a whole set of digitalized MRI features (myocardial stiffness and mobility, vascular wall condition, etc.) and trained a deep learning model that produces an individual “heart age” estimate. They then compared this estimate with a fat map obtained from body MRI and with clinical and biochemical indicators. In separate analyses, the team also looked at genetic predispositions to “male” (abdominal) and “female” (gluteofemoral) types of fat distribution: a genetic predisposition to a “pear” shape in women correlated with a younger heart. This strengthens the causal link between fat distribution, not just body mass.

Main results

First: visceral fat = accelerated aging of the heart, even if the body mass index is “normal” and the person exercises. Second: gender differences are fundamental - in men, the “apple” (belly) is especially strongly associated with accelerated aging, while in women, the “pear” (hips/buttocks) looks protective. Third: signs of systemic inflammation were found in the blood of carriers of excess visceral fat, which fits well with the mechanistic ideas about how “bad” fat interferes with the vascular wall and myocardium. And, finally, BMI alone says almost nothing about the “age” of the heart - where the fat is stored is more important.

Why Where You Store Fat Is More Important Than the Number on the Scale

Visceral adipose tissue is not an inert calorie storehouse, but an active endocrine organ that secretes pro-inflammatory factors and changes the metabolism of the liver and blood vessels. Subcutaneous "peripheral" fat in women, on the contrary, often behaves metabolically neutrally or even protectively, redistributing lipids away from vital organs. Therefore, two people with the same weight can have different heart ages - and different risks. The new work shows exactly this in a large cohort with an objective MRI picture and an AI assessment of organ aging.

What does this mean for practice - not only "losing weight", but also where

• Focus on waist and visceral fat. Waist circumference and waist-to-height ratio are simple markers of central obesity and are better indicators of “at-risk” fat than BMI.
• Cardio + strength training is a great combination. They help reduce visceral fat, improve insulin sensitivity and reduce inflammation.
• Eating with control of ultra-processed foods and excess calories. This reduces excess "flows" of lipids to the liver and visceral depots.
• Medical options - as indicated. If abdominal fat is high and there are associated risk factors, the doctor may discuss weight loss pharmacotherapy (e.g. GLP-1 agonists). The main thing is their role in reducing the visceral component.

These steps address the "root of the problem": redistributing and reducing harmful visceral fat, which evidence suggests may be closely linked to slowing cardiac aging.

A few important caveats

This is an observational study using AI: it finds robust associations in a large UK Biobank sample, but is not a randomised intervention. The ‘cardiac age’ assessment is a validated but modelled MRI metric, not an organ ‘passport’. Although genetic predisposition signals strengthen the case for a mechanistic link, translating the results to an individual patient requires clinical judgement and consideration of co-factors (blood pressure, glucose tolerance, lipids, etc.).

Context and Next Stop

The work fits into a broader “precision prevention” agenda: instead of an average BMI, a personalized body composition map + objective metrics of organ aging. A logical next step is prospective studies where targeted reduction of visceral fat (diet, exercise, medication) will be tested for its ability to slow the growth of “heart age” and reduce real events (heart attack/stroke). On the practical side, this encourages clinics to more actively use central obesity assessment and talk to patients about the “quality” of fat, not just kilograms.

Original source: Declan P. O'Regan et al. Sex-specific body fat distribution predicts cardiovascular ageing. European Heart Journal (online 22 August 2025), doi: 10.1093/eurheartj/ehaf553.