Hidden Fat in Your Muscles Is Harming Your Heart – Here’s Why

We all know that carrying excess fat isn’t great for our health. But what if I told you that it’s not just the fat under your skin or around your belly that matters?

A recent study (Souza ACDAH, et.al., 2025) found that fat stored inside your muscles—called intermuscular adipose tissue (IMAT)—could be a major warning sign for heart disease, even if your weight or BMI seems normal. Let’s break it down.

The Hidden Danger: Fat Inside Your Muscles

Most people focus on BMI (body mass index) to measure health, but this study shows that BMI alone doesn’t tell the whole story. Researchers followed 669 patients for six years and found that:

• More muscle fat (IMAT) = Higher risk of heart problems
• More lean muscle and healthy fat under the skin (SAT) = Lower risk
• BMI wasn’t the best predictor of heart disease—it was what’s inside your muscles that mattered.

What This Means for Your Heart

The study also looked at coronary flow reserve (CFR), which measures how well your heart’s small blood vessels function. Lower CFR (meaning poorer blood flow) was linked to both higher muscle fat and higher risk of heart attacks, heart failure, and even death.

In fact, for every 1% increase in muscle fat, the risk of serious heart problems jumped by 7%!

Who’s Most at Risk?

People with both poor muscle quality (more IMAT) and coronary microvascular dysfunction (CMD) had the highest risk of heart disease—even if their BMI was in a normal range.

What Can You Do?

The good news? Your muscle health is something you can improve! Here’s how:

1. Build Lean Muscle – Strength training helps reduce IMAT and improves muscle quality.
2. Eat Smart – Focus on protein, healthy fats, and fiber to fuel your muscles and keep inflammation low.
3. Stay Active – Walking, cardio, and resistance exercises boost heart function and circulation.
4. Get Checked – If you have risk factors (like obesity, diabetes, or a family history of heart disease), talk to your doctor about heart screening beyond just BMI.

Final Thoughts

This research is a wake-up call: Your body composition matters more than your weight alone when it comes to heart health. Instead of just watching the scale, focus on building strong, lean muscle and reducing hidden fat inside your body.

Want to take control of your health? Start moving, start lifting, and fuel your body with the right nutrients. Your heart will thank you!

Learn More About Our Exercise Program

For additional ways to boost your muscle health and overall well-being, check out our Exercise for Maximum Benefits program. This easy-to-implement, time-efficient routine is designed to help you reap the benefits of exercise without disrupting your busy schedule.

Reference

Souza ACDAH, Troschel AS, Marquardt JP, Hadžić I, Foldyna B, Moura FA, Hainer J, Divakaran S, Blankstein R, Dorbala S, Di Carli MF, Aerts HJWL, Lu MT, Fintelmann FJ, Taqueti VR. Skeletal muscle adiposity, coronary microvascular dysfunction, and adverse cardiovascular outcomes. Eur Heart J. 2025 Jan 20:ehae827.