She studied in the United States running for Seattle Pacific University. She has continued running into the Masters athletics age groups. She is the current World Record holder in the W50 division at 1500 metres, 3000 metres, 5000 metres and 10,000 metres. She also has a pending W50 world record for the mile. Karlshøj starred as a personal trainer for DR2 runners who ran the New York Marathon in Tema Saturday in November 2006. She is a physiotherapist by Team Denmark in Aarhus and lecturer in business/sports clubs.
