Stress causes reversible increases in biological age

What's the news: Biological age can change rapidly in both directions during and after episodes of severe stress.

Why should we believe it: This news comes from a study published two weeks ago by a team of scientists from Harvard, Duke University, and UCLA. The team includes longevity science heavy-hitters Vadim Gladyshev and Steve Horvath, who is one of the pioneers of biological aging clocks.

The study had two parts. One part looked at the aging of mice in heterochronic parabiosis, in which a young mouse is surgically joined to an old mouse. In this freakish treatment, the young mouse experienced aging on "epigenetic, transcriptomic, and metabolomic levels." But once the two mice were separated, the aging of the young mouse was reversed.

The second part of the study looked at natural experiments including major surgery, pregnancy, and severe COVID-19 in humans. The results were similar. Big episodes of trauma or stress age us, but when such episodes pass, our biological age actually reverses to a more youthful state.

Why this is a big deal: As the authors put in the paper, we tend to imagine aging as an "ever-increasing trajectory of damage accumulation and loss of function." Or in the words of Pink Floyd, the passing of time only ever makes us "shorter of breath and one day closer to death."

But the current study says no. Biological aging is reversible. In fact, it's already reversed naturally by the body during recovery of extreme cases of trauma. It's reasonable to hope that scientists will figure out how to trigger such natural rejuvenation even when we aren't recovering from surgery or pregnancy.

So what specifically can you do now? Your Long Youthspan editor sees two practical takeaways from the current study:

1. If you have experienced a major stress event in your life, allow yourself adequate space and time to recover. It could literally save your life, if not today, then some years down the line.

2. Take longevity lifestyle measures seriously — prioritize sleep, avoid ultraprocessed foods, and exercise regularly. Not only will such measures slow down your aging, but in some cases, they might even be able to reverse your biological age.