04/07/2026
I spent three days in a room full of geneticists. Here’s what actually stuck.
For years, twin studies put the genetic contribution to lifespan at around 20-25% - mostly down to lifestyle and luck. A new analysis out of Leiden University Medical Center (the same group behind the Leiden Longevity Study) revisited that number, and once they separated deaths from accidents and illness from deaths driven by ageing itself, the genetic contribution came out closer to 50%. More than double the earlier estimate.
Sleep disruption might not just be a symptom of one condition. It looks like it’s a thread running through several - depression, eating disorders and more. (Sheridan, Pain, Watson, Herle et al., medRxiv preprint, 2025.) Which means working on your sleep isn’t just self-care - it might be doing more than one job at once.
And the one that needs zero genetics degree to use: every extra 1,000 steps a day is linked to a 9% lower risk of depression, based on a review of 33 studies and 96,000+ adults. (Bizzozero-Peroni et al., JAMA Network Open, 2024.)