How does a developing heart know how big to grow? 

Northwestern Medicine scientists have uncovered an unexpected part of the answer: lymphatic vessels, long known for transporting fluid and immune cells, also send signals to different cardiac cell types that help control heart growth. Understanding this communication may ultimately have implications for heart repair after a heart attack and could inform future approaches for investigating congenital heart defects, the study authors said. The study was in mice and ‘mini-hearts’ — lab-grown human 3D organoids that mimic features of the developing heart.

A study of more than 5,500 adolescents in the US found that those who took more daily steps at age 11 to 12 had fewer mental health problems a year later. 

The relationship held all the way up to 12,000 or more steps a day, with no sign of the benefit levelling off within this data. 

Adolescents with the highest step counts also showed differences in brain areas linked to movement and mood and these differences explained associations between step counts and mental health.