Actograms showing activity data (vertical black bars) divided into light
phase (daytime, from 6:00 a.m. to 5:45 p.m., beige horizontal bar on
top) and dark phase (night time, from 5:45 p.m. to 6:00 a.m., gray
horizontal bar on center top). Yellow lines represent the variation in
light throughout the day (24h period). Horizontal red bar represents
when individuals were awake, and blue area indicates sleep period, with
the lighter blue area indicating rest, and dark blue arrow head
representing when subjects pressed a button on Actiwatch 2 to mark when
they went to bed and when they woke up in the morning. Graph (A)
illustrates a healthy subject; (B) a diabetic subject showing high
instability between days, (C) a diabetic subject showing low rhythm
amplitude, and (D) a diabetic subject showing high fragmentation.