Glucose trend, trailing 90 days

Poincaré map help

This chart is a density delay map (“glucose-at-a-glance”): each point pairs glucose at time t with glucose a short lag later. It summarizes short- and longer-term dynamics that a single average or A1c cannot show. Method based on Henriques et al., J Diabetes Sci Technol (2014).

• Diagonal (y = x): readings that barely change over the lag sit near this line.
• Width off the diagonal: short-term wobble over the chosen lag (larger spread = more minute-to-minute variability).
• Stretch along the diagonal: how widely overall glucose levels range over the recording.
• Colors: warm/brown zones are pairs you visit often; cool/blue zones are uncommon transitions.
• Tight warm cluster: often a preferred “attractor” range (more stable control).
• Large smeared cloud: broader swings and less stable set-point behavior.
• Lag control: 5 min emphasizes immediate change; 15–60 min widens the short-term axis and shows slower evolution.
• SD1 / SD2: ellipse descriptors—SD1 is short-term variability (perpendicular to the diagonal), SD2 longer-term (along it). SD2/SD1 is the shape ratio.

Hypo- and hyperglycemia show up as density in low or high axis regions. Compare maps across time windows or devices to see whether variability structure changed, not only the mean.