Themistoklis Katsimichas is a Greek cardiologist, who as of June 2022 works at the Department of Cardiology of Hippokrateion General Hospital in Athens, Greece, and the Heart Center for Athletes and the Young, a division of the First University Department of Cardiology at the same hospital. His main interests are hypertension, sports cardiology, and the cardiovascular implications of changes in the human gut microbiota. Dr. Katsimichas earned his MD from the Medical School of the University of Athens in Greece and his PhD from the Graduate School of Medicine of the University of Osaka in Japan, where his research focused on the association of the human gut microbiota with heart failure. He completed his fellowship in Cardiology and was Board certified in Greece in June 2022. He likes travelling, photography, and rock music; he used to be a semi-professional rock musician. Other than Greek, he speaks native-level English and can converse in Japanese and German.