In Choosing to Run, released Tuesday, Des Linden, 39, details how in the summer of 2017, she was diagnosed with a thyroid condition after struggling for months with intense exhaustion that made running nearly impossible.

Linden had difficulty accepting her diagnosis at first because it meant she would have to go on a synthetic thyroid hormone medication — something she had watched other athletes in the sports abuse to try and gain an advantage. As one of the most vocal people in running calling out doping, Linden at first questioned if she was a hypocrite for needing the medication.

Read the full story in People.