Heading a football changes blood patterns in the brain, according to new study

A study published in the journal Brain Injury reveals that playing football can alter blood patterns in the brain. Researchers analyzed blood samples from professional footballers and found changes in micro RNA levels after heading the ball. Micro RNAs are crucial for protein production and cell function, and their alteration is linked to cognitive functions and Alzheimer's disease. The study suggests that micro RNAs could serve as biomarkers for detecting brain injuries. In response to such findings, the Football Association in England has limited high-force headers in training sessions.

What were the findings regarding repetitive headers and micro RNAs?

What new guidance did the Football Association in England introduce regarding headers?