The cellular aging myth gets a major update — and exercise might be the fix

For decades, scientists assumed that autophagy — the body's built-in cellular cleanup system — simply declines with age, contributing to disease and decline. A new study published in Aging Cell by researchers at Sanford Burnham Prebys is turning that assumption on its head.

Analyzing blood, skin, and neuron samples from adults aged 23–72, the team found that autophagy doesn't follow a single trajectory. It can go up, down, or stay flat — depending on the cell type and the person's sex. In male skin cells, recycling slowed with age; in female skin cells, it held steady; and in induced neurons from women, it actually increased with age.

Perhaps the most counterintuitive finding: in adults over 70, higher autophagy was linked to poorer physical function — lower aerobic fitness, higher BMI, weaker grip strength, and elevated resting heart rate. More cellular cleanup wasn't necessarily better.

Key Takeaways:

• Gene expression levels — a common proxy measure — did not reliably reflect actual autophagy activity, a caution for researchers using static transcription data
• Cell type and biological sex both significantly shape how autophagy changes with age
• A 12-week gentle exercise program in adults aged 77–88 (n=5) lowered autophagy in blood cells toward younger-adult levels and improved physical performance

Why it matters: These findings suggest that future therapies targeting autophagy for healthy aging can't be one-size-fits-all — they'll need to account for age, sex, and specific cell types. For clinicians, it's a reminder that exercise remains one of the most accessible tools for supporting healthy aging at the cellular level.