Figure 1.

(a) Age and gender characteristics of the considered study cohort of disease-free humans (males blue, females orange). The total numbers of data sets (nights) are shown for each age group. (b) Proportion of sleep stages on total time in bed for all subjects sorted by age (from left to right). The colors indicate the states, from bottom to top: wake state - dark blue, light sleep stage 1 - yellow, light sleep stage 2 - green, deep sleep stages 3 and 4 - red, and REM sleep - light blue. (c) Sleep stage distribution averaged over 10 years for all subjects (large bars in the center), and separately for females (left) and males (right); colors and order as in (b).