The second episode of Echoes of Impact features Dr Helen Murray, Dr Stephen Kara and ex-All Black Conrad Smith.

Dr Murray, from The Centre for Brain Research at University of Auckland is also captain of Aotearoa's ice hockey team. She talks about what happens inside your head when you get a brain injury and how the tragic death of Billy Guyton, a former Māori All Blacks player, could help with a breakthrough in the understanding of brain injuries.

Dr Kara, Sport and Exercise Physician at Axis Sports Clinic, then talks about his history of working with athletes with concussions and how his mission is to help ensure concussions don't continue to impact sports players after they've given up playing.

Meanwhile double World Cup winner Conrad Smith, who's now Head of High Performance and Player Welfare at International Rugby Players, talks about his history of head knocks and whether he'd allow his children to play rugby.

Echoes of Impact is written and hosted by veteran journalist Alison Mau.