Why do some people stay mentally sharp after surgery while others decline even when their brains look identical on scans?

In this episode, I explore one of the biggest mysteries in brain health: why two people with the same MRI, the same amyloid burden, and the same risk factors can age so differently. My guest, Dr. Leah Acker, a Harvard-MIT–trained physician-scientist and Duke anesthesiologist, studies the hidden rules of brain resilience and what stress reveals about cognitive decline.

As we talk, Dr. Acker explains how surgery acts as a “stress test for the brain,” exposing vulnerabilities years before symptoms show up. We break down the links between anesthesia, delirium, sleep, heart rate variability, inflammation, and early neurodegeneration, and why postoperative delirium can increase dementia risk up to 12-fold. She also explains why simple EEG changes can predict who is most vulnerable during stress.

We also dive into the future of brain science—from personalized anesthesia to breakthroughs in functional MRI and new Alzheimer’s biomarkers.

If you or a loved one is facing surgery, or if you want to understand how the aging brain really works, this episode is essential. Tune in to learn how to prepare, protect your brain, and build long-term cognitive resilience.

“ I tend to think of surgery and anesthesia as a stress test for the brain. It's an emotionally stressful event in general…On top of that, there's a lot of physiological stress that comes with surgery.”

~ Dr. Leah Acker

In this Episode

00:00 - Introduction to Dr. Leah Acker

07:58 - Post-operative delirium and dementia connection

11:08 - Heart health and its impact on inflammation and healing

14:51 - How long does anesthesia stay in the body?

19:36 - Pre-operative preparation to minimize the stress of surgery

23:19 - EEG, alpha waves, and what they reveal about brain health

27:31 - Surgery as a stress test for the brain

33:27 - Tips for patients who have just had a major surgery

44:06 - Biomarkers to determine brain function and Alzheimer's risk

47:23 - What makes the brain respond well to stress?

53:03 - The future of brain research and personalized patient care

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