Hartman represented her nation at four World Sprint Speed Skating Championships for Women and three World Single Distance Speed Skating Championships. At the World Sprint championships she competed in 2003 (finishing 22nd overall), 2008 (finishing 9th overall), 2009 (finishing 21st overall) and 2010 (finishing 22nd overall). At the 2008 World Single Distance Speed Skating Championships she competed in the 500 metres event (18th) at the 2009 World Single Distance Speed Skating Championships she competed in the 500 metres event (19th) and 1000 metres event (18th); and at the 2012 World Single Distance Speed Skating Championships she competed in the 1000 metres event (22nd). She also competed at other international competitions, including at ISU Speed Skating World Cups.