Figure 5.

Deceleration capacity (DC) versus age for (a) wakefulness, (b) light sleep S2, (c) deep sleep S3 and S4, and (d) REM sleep for all subjects (black filled diamonds), males (dark gray open triangles up), and females (light gray open triangles down). We plotted median values and both quartiles Q25 and Q75 as lower and upper errors bars, respectively. Solid straight lines are linear fits to the medians for all subjects; the formulas of the separate fits for males and females are printed in the top right corner. Black and gray dashed lines indicate risk levels previously defined for infarction patients: high cardiac risk DC < 2.5 ms and low cardiac risk DC < 4.5 ms.