A biological clock that speeds up aging; RFK Jr. revives the Presidential Fitness Test; spring break, the deadliest drive — Morning Medical Update

A biological clock that speeds up aging

An Edinburgh-led team ties DNA methylation directly to age-related disease.

A rare genetic condition that causes accelerated aging offers the first evidence that the body's "biological clock" may actively drive age-related disease rather than simply mark the passage of time, according to a study published in Nature Genetics. An international team led by the University of Edinburgh identified the condition, called Heyn-Sproul-Jackson syndrome, in which DNA methylation marks accumulate at the same sites as in normal aging but far faster.

Patients developed conditions typically seen later in life much earlier, including reduced blood cell production, osteoporosis and hair loss. In a mouse model, added methylation marks were associated with metabolic changes linked to diabetes and high cholesterol, and adult stem cells crucial for tissue repair began to fail, which the researchers said could help explain age-related decline.

"By studying a rare disease in depth, our colleagues have gained new insight into the biology of human ageing and identified promising directions for future rejuvenation therapies," said Joris Veltman, M.Sc., director of the Institute of Genetics and Cancer. The team cautioned that further studies are planned to confirm how methylation reduces tissue renewal and whether the changes can be reversed.

Kennedy revives Presidential Fitness Test

HHS launches GetActive.gov/kids alongside a fall return of school fitness testing.

Health and Human Services (HHS) Secretary Robert F. Kennedy Jr. announced the return of the Presidential Fitness Test and launched GetActive.gov/kids at an event June 29 at the Boys & Girls Club of Atlantic City, New Jersey. Beginning this fall, schools will administer the test using what HHS described as updated, age-appropriate standards measuring strength, endurance, speed and agility.

The department framed the effort as a response to childhood health trends, citing figures that nearly 1 in 5 children is overweight or obese and that 77% of young Americans are ineligible for military service, with poor health and fitness among the reasons. HHS said it is partnering with the Boys & Girls Clubs of America, WWE and community organizations over the summer to prepare children for the test, and that states led by both parties have committed to bringing it back.

"By bringing back the Presidential Fitness Test and launching GetActive.gov/kids, we are giving parents, schools, and communities the tools to help children build healthy habits, strengthen their bodies, and discover what they’re capable of achieving," Kennedy said.

Spring break, the deadliest drive

Florida crash data over 12 years points to traffic density, not just drunk driving.

Spring break, not the Thanksgiving-to-New Year's stretch, is the deadliest time of year to travel Florida's roads, according to a study published in Risk Analysis.

Michael T. French, Ph.D., and Gulcin Gumus, Ph.D., analyzed 12 years of crash data across all 67 Florida counties from 2011 to 2022, more than 42,000 observations, and found fatalities and non-fatal injuries elevated during the late-February-to-early-April window.

Young drivers, out-of-state drivers and non-motorists such as pedestrians and cyclists saw fatal and non-fatal injury rates an estimated 10% to 15% above baseline, with out-of-state driver crashes up as much as 37%. Alcohol-related crashes showed no significant spike, suggesting traffic volume and unfamiliarity with local roads matter more than intoxication.

"This research shows that targeting drunk driving alone is not the best strategy," French said, pointing instead to density management, expanded public transportation and stepped-up enforcement. The authors cited recent measures in Miami Beach — DUI checkpoints, more police and pedestrian protection zones — as the kind of coordinated approach they recommend.