Figure 6.

Gliding spectral window (surface chart). Systolic blood pressure was automatically measured around the clock by a 62-year old woman with recurring episodes of adynamic depression occurring twice a year and lasting 2–3 months. Complementary nonlinear analyses (not shown) indicate the coexistence of about 24.0- and 24.8-hour components, their relative prominence alternating between wellness and adynamic depression. Changes in the most prominent circadian period as a function of time are apparent from the changes in amplitude (shading) and location along the vertical scale. © Halberg Chronobiology Center.