Fidji Simo, who stepped down as OpenAI's CEO of Applications on Thursday, revealed she has been living with postural orthostatic tachycardia syndrome (POTS) for the past seven years and shared that she regrets not following health advice from Meta CEO Mark Zuckerberg. According to Business Insider, Simo said in a social media post that she became ill while working at Facebook, where she spent a decade in various leadership roles. She wrote that despite repeated encouragement from doctors, colleagues, friends and loved ones to slow down, she continued to prioritise work, noting that two years after she got sick, Facebook offered her the opportunity to take a full year of medical leave, but she immediately said no. Simo stated, "At the time, Zuck told me I should play the long game. I wish I had listened." She added that her determination and willingness to seize opportunities helped her go from a small town in southern France to achieving more than she had imagined possible by the age of 40, but her perspective on success has evolved. Simo wrote that she is learning "grit and endurance are not the only skills required to have impact over decades." She described it as "jarring" to spend her days at OpenAI building what she believes is the future while "navigating a disabling disease that still has no cure." Simo will transition from her role as CEO of Applications to a part-time advisory position. OpenAI CEO Sam Altman reshared her post on X and