Average waveforms of circadian variables and amplitude reduction.

<p>Average waveform of subjective alertness, plasma cortisol, core body temperature and plasma melatonin during a constant routine in participants with a reduction in melatonin amplitude >50% (closed symbols; n = 7) compared to those in whom the reduction was <50% (open symbols; n = 7). All data are aligned with the timing of the fitted minimum of the core body temperature rhythm. Error bars indicate 1 SEM.