For years the female body in athletic performance has gone understudied, until recently.

India meets Richard Burden from the English Institute of Sport who is researching the effect of hormones on female performance whilst also building key technology in the field to do onsite hormone testing. India is also joined by GB pentathlon athlete Jess Varley who is part of this research and who has tailored her training around her menstrual cycle to reap extraordinary results.

Credits: Presented by India Rakusen. Producer: Jorja McAndrew. Series Producer: Ellie Sans. Executive Producer: Suzy Grant. Original music composed and performed by Rebekah Reid. Sound design by Charlie Brandon-King.

Special thanks to all contributors and audio diarists.

A Listen production for BBC Radio 4 and BBC Sounds.