🧬 Rethinking Healthspan: Why We’re Missing the Most Important Years

The word healthspan has become a buzzword in longevity circles. It’s often defined as the number of years we live in good health, free from disease and disability. But what if this popular definition is leaving out a critical phase of life—the very years when our bodies are quietly adapting, compensating, and starting to falter before we get diagnosed with anything at all?

A new study published in Ageing Research Reviews by Masfiah et al. (2025) tried to untangle the confusion by reviewing over 14,000 papers on healthspan. After a rigorous screening process, 207 articles were analyzed. The findings? Nearly every study defined healthspan in a slightly different way—but almost none of them acknowledged the gray zone before disease: the subtle, accumulating toll of stress, exhaustion, and metabolic wear-and-tear.

That’s where a concept called Exposure-Related Malnutrition (ERM) comes in—and why it might be the missing piece in how we measure, extend, and protect healthspan.

📉 What the Study Found—and Missed

The review found that most definitions of healthspan focus on the absence of chronic disease or disability. Some use objective metrics like the onset of diabetes or dementia, while others rely on performance-based measures like aerobic capacity or activities of daily living.

Yet not a single definition directly addressed the pre-disease phase—a time when functional capacity is declining, energy systems are strained, and the body is working harder just to maintain balance. In clinical practice, this is often when people start saying,

“I’m not sick, but I’m not thriving either.”

That’s ERM.

🧠 What Is Exposure-Related Malnutrition?

ERM refers to a subclinical state of nutritional and functional compromise that emerges under chronic stress—whether that’s psychological, metabolic, environmental, or immunological. It's not about eating too little; it’s about the body having insufficient resources to keep up with demand.

People with ERM may have normal lab tests. They may not meet criteria for a disease. But they often show signs of fatigue, muscle loss, slower recovery, or reduced cognitive resilience. These early warning signs are easy to miss—and rarely measured.

ERM sits in the gap between “health” and “disease”—the same gap that current healthspan definitions overlook.

🏃 Functional Tests That Can Spot ERM Early

One of the most powerful ways to detect ERM is through functional performance testing—simple but sensitive tools that measure how the body is actually working, not just what’s in the lab report.

Here are a few examples that could complement ERM recognition:

• Gait speed and walking tests (e.g., 6-minute walk test): Early indicators of fatigue and cardiorespiratory compromise.

• Grip strength and muscle testing: Reflects protein reserves and inflammation-related catabolism.

• Balance and mobility tests (e.g., timed up and go, single-leg stance): Reveal neuromuscular integrity and adaptive effort.

• VO₂ max or submaximal aerobic tests: Identify reduced mitochondrial and cardiovascular capacity.

• Functional independence scores (e.g., ADLs/IADLs): Decline subtly before disease, signaling early energy deficit.

Unlike disease-based thresholds, these tests can capture compensated dysfunction—the body doing more with less, right before it starts to break down.

🔄 A New Definition of Healthspan?

If we want to truly extend healthspan, we need to expand our definition. It shouldn’t just start when we’re free from disease. It should start when our systems are still resilient—and end when that resilience is lost, even if disease hasn’t yet appeared.

That’s the space where ERM lives—and where early intervention can change the course of aging, vitality, and well-being.

🧩 Bridging the Gap

As the science of longevity moves forward, ERM offers a vital framework to bridge the blind spot between health and disease. By integrating functional tests, resilience markers, and a life-course perspective, we can build a more accurate, compassionate, and actionable understanding of healthspan.

Because you don’t have to wait until you’re sick to start recovering.

Have you ever felt like you're not sick—but not really well either?

You’re not broken. You might just be running on empty.

That’s not weakness. It’s a sign. And there are tools to help.

Masfiah, S., Kurnialandi, A., Meij, J. J., & Maier, A. B. (2025). Definitions of healthspan: A systematic review. Ageing Research Reviews, 111, 102806. https://doi.org/10.1016/j.arr.2025.102806

#Healthspan, #Exposure-Related Malnutrition (ERM), #Functional Decline, #Resilience Testing, #Subclinical Aging