Figure 12.

Impact of age on the 24-hour profile of plasma cortisol in healthy nonobese men. Data are shown at each time point as mean + SEM. The two age groups included eight men that were matched for body mass index. Note the higher nadir level, the reduced amplitude of the overall rhythm, and the earlier onset of the early morning rise in older participants. The overall disruption of the 24-hour cortisol profile is likely to contribute to and/or exacerbate age-related metabolic, immune, and cognitive deficits. [Redrawn from E. Van Cauter et al: Age-related changes in slow wave sleep and REM sleep and relationship with growth hormone and cortisol levels in healthy men. JAMA. 2000;284(7):861–868 (313), with permission. © American Medical Association.]