Lifetime in Motion Unveils Aging's Architecture

Researchers track fish behaviors to reveal how aging unfolds in individuals

Mar. 13, 2026 at 5:09am

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A new study supported by the Knight Initiative for Brain Resilience at Stanford's Wu Tsai Neurosciences Institute has found that by midlife, an animal's everyday behaviors can signal how long it is likely to live. Researchers put scores of short-lived fish under continuous, lifelong surveillance to explore how behavior and aging are linked, and discovered that fish on paths to a longer life swam with greater vigor, reached higher speeds, and were more active during daylight hours compared to fish that went on to have shorter lives.

Why it matters

While the research was conducted in fish, the findings raise the possibility that tracking subtle, daily behaviors like movement and sleep, now routinely captured by wearable devices, may offer clues about how aging unfolds in people. The study also suggests that aging may involve long stretches of relative stability punctuated by brief periods of rapid change, rather than a smooth, gradual process.

The details

Researchers built an automated system in which individual fish lived in separate, camera-monitored tanks, capturing every moment of the animals' lives. They extracted detailed information about the animals' posture, speed, rest, and movement, identifying 100 distinct "behavioral syllables." They found that by early midlife (70 to 100 days of age), fish that would go on to live shorter or longer lives were already behaving differently, with those on paths to a longer life sleeping mainly at night and swimming with greater vigor. Using machine-learning models, the researchers showed that just a few days of behavioral data from middle-aged fish were enough to forecast lifespan.

  • The research was published in Science on March 12, 2026.
  • The study followed individual fish through their entire adult lifespans, which typically range from 4 to 8 months.

The players

Claire Bedbrook

A postdoctoral scholar in the Department of Bioengineering at Stanford Medicine and Stanford Engineering, and a lead author of the study.

Ravi Nath

A postdoctoral scholar in the Department of Genetics at Stanford Medicine, and a lead author of the study.

Anne Brunet

The Michele and Timothy Barakett Professor of Genetics at Stanford Medicine, and a senior author of the study.

Karl Deisseroth

The D.H. Chen Professor in the Departments of Bioengineering at Stanford Medicine and Stanford Engineering, and of Psychiatry and Behavioral Sciences at Stanford Medicine, and a senior author of the study.

African turquoise killifish

A short-lived vertebrate species used in the study, with a typical lifespan of 4 to 8 months.

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What they’re saying

“Behavior is a wonderfully integrated readout, reflecting what's happening across the brain and body. Molecular markers are essential, but they capture only slices of biology. With behavior, you see the whole organism, continuously and non-invasively.”

— Anne Brunet, Michele and Timothy Barakett Professor of Genetics at Stanford Medicine

“Behavioral changes pretty early on in life are telling us about future health and future lifespan.”

— Claire Bedbrook

“We now have the tools to map aging continuously in a vertebrate. With the rise of wearables and long-term tracking in humans, I'm excited to see whether the same principles—early predictors, staged aging, divergent trajectories—hold true in people.”

— Claire Bedbrook

What’s next

The researchers plan to test whether aging paths can be modified through targeted interventions, including changes to diet as well as to genes that may help influence the pace of aging. They also aim to explore whether sleep itself can be manipulated to promote healthier aging, and whether intervening early, before decline sets in, can alter an individual's aging path.

The takeaway

This study suggests that by tracking an individual's daily behaviors, such as movement and sleep patterns, it may be possible to predict their future lifespan and identify early signs of accelerated aging. These findings could lead to new ways of promoting healthy aging in both animals and humans.