Poor sleep hygiene in college tend to persist through the senior year, a new study suggests. Students whose sleep hygiene worsened during college also showed a greater decline in their GPA. "Night owls" showed greater declines in GPA from high school to college and had a lower freshman GPA (2.84) than morning and intermediate types combined (3.18). Night owls shifted more toward a morning chronotype by their senior year, when there were no longer GPA differences between chronotypes.