NAD⁺ Depletion and the Biology of Exhaustion

We’ve long known that chronic stress is harmful. We’ve also known that mitochondria and NAD⁺ sit at the heart of aging and chronic disease. What has remained unclear is why people can appear metabolically “stable” for years—sometimes decades—while slowly losing resilience, recovery capacity, and health.

A recent study by Chaubey et al. (2026) offers a crucial piece of that puzzle.

Their findings align remarkably well with the Exposure-Related Malnutrition (ERM) framework, which views many modern chronic conditions not as failures of willpower or isolated organ defects, but as failures of recovery under persistent energetic constraint.

Let’s unpack why this matters—and where it opens new doors for clinical care.

The Key Finding: Survival Can Continue While Recovery Fails

In human brain microvascular endothelial cells exposed to oxidative stress, Chaubey and colleagues made a striking observation:

• Basal mitochondrial respiration remained intact

• Maximal respiration and spare respiratory capacity collapsed

• NAD⁺ restoration rescued reserve capacity—without increasing baseline respiration

In simple terms:

Cells had enough energy to survive, but not enough flexibility to recover.

This distinction is subtle—but profound.

Traditional thinking often equates “normal ATP” or “normal baseline metabolism” with health. This study shows that such measures can be misleading. What fails first is not survival energy, but recovery energy.

NAD⁺: The Currency of Recovery, Not Just Energy

Why does this happen?

The answer lies in NAD⁺, a molecule often discussed as an “anti-aging” supplement but far more important than that.

Chaubey et al. demonstrate that under chronic stress:

• NAD⁺ is progressively depleted

• Consumption increases via PARPs (DNA damage response) and sirtuins (stress adaptation)

• Redox regeneration of NAD⁺ becomes insufficient

• Mitochondria lose reserve capacity, even though basal respiration persists

This creates a state where cells are metabolically alive but biologically stuck.

And this is exactly what the ERM framework predicts.

How This Fits the ERM Framework

ERM describes a condition where energetic demand chronically exceeds recovery capacity, even when calorie intake appears adequate and no advanced disease is present.

Chaubey et al. provide cellular-level evidence for this logic:

ERM Concept	Chaubey et al. Evidence
Survival prioritized over repair	Preserved basal OCR
Recovery capacity fails first	Loss of spare respiratory capacity
NAD⁺ as a bottleneck	Rescue of reserve capacity via NAD⁺ restoration
Stress persists despite “normal labs”	ATP and basal respiration remain intact

In ERM terms, this is mitochondrial congestion: energy substrates and stress signals continue to flow, but the system can no longer process them efficiently enough to support renewal.

Why This Matters Clinically

This study helps explain why so many people experience:

• Persistent fatigue

• Poor exercise tolerance

• Brain fog

• Slow healing

• Inflammatory and metabolic drift

…despite “normal” blood tests and adequate nutrition.

From a clinical perspective, it suggests a shift in focus:

From:

• Calories alone

• Static biomarkers

• Symptom suppression

Toward:

• Recovery capacity

• Mitochondrial reserve

• NAD⁺ balance and redox flexibility

• Patterns of bioenergetic strain over time

Future Clinical Translation: Beyond Simple Supplementation

Importantly, Chaubey et al. do not imply that indiscriminate NAD⁺ supplementation is the solution.

Instead, their work points to a more nuanced future:

• Identifying early loss of reserve capacity, before overt disease

• Recognizing when stress adaptation has become biologically entrenched

• Designing interventions that reduce NAD⁺ consumption, not just boost supply

• Supporting true recovery phases, not perpetual activation

In ERM-informed care, this means addressing:

• Chronic inflammatory signaling

• Sleep and circadian disruption

• Psychological and environmental stressors

• Protein and micronutrient sufficiency for repair

• Timing and pacing of metabolic challenges (exercise, fasting, workload)

A New Way to Think About Aging and Chronic Disease

Perhaps the most important takeaway is this:

You may not be broken. You may be exhausted at a cellular level.

Chaubey et al. provide rigorous experimental evidence that recovery failure can precede degeneration, and that restoring recovery capacity is both measurable and, potentially, modifiable.

This reframing—central to the ERM framework—opens the door to earlier detection, gentler intervention, and more humane medicine.

Stress is inevitable.

But recovery failure is not.

Chaubey, S., et al. (2026). Restoration of NAD⁺ homeostasis reverses functional decline in experimental models of Alzheimer’s disease. Cell Reports Medicine. Advance online publication. https://doi.org/10.1016/j.xcrm.2025.102535