Neuroscience evidence suggests that physical exercise can influence brain function and structure, both immediately and in the long term. The ‘Fit to Study‘ project is a randomised controlled study to test the impact on academic performance (as well as fitness, wellbeing and cognitive function) of a teacher training intervention designed to try to optimise the content of PE for brain and cognitive function during secondary school (Year 8) Physical Education (PE) lessons. The project aims to rigorously test the impact of this intervention in 100 state-funded secondary schools.