Figure 3

Right and Left Mean Acrophase for Young vs. Older Male and Female Subjects. Right (A) and Left (B) mean acrophase (± standard error) for young and older males and females. Males are shown in black (young) and dark gray (older). Females are shown in white (young) and light gray (older). There were main effects for sex (p = 0.002) and age (p = 0.040). The four age and sex groups analyzed show peak activity at different times of the day. The order is as follows ("<" means "peaks before"): older females < young females < older males < young males.