Protocol.

<p>Rasterplot, including two baseline days, twelve 20-h cycles, and discharge day of an example subject with a habitual bedtime of midnight. Blue bars, baseline and discharge wake episodes in normal room light (∼90 lux); solid back bars, scheduled sleep (0 lux); gray bars, wake episodes in dim light (∼1.8 lux); red bars, timing of the test batteries; dotted line illustrates the circadian core body temperature minimum throughout the protocol, with an average circadian period of 24.09h in these subjects. Each test battery consisted of a mental, tilt, and exercise stress (S) test, each preceded and followed by a baseline (B) and recovery (R) episode. The timing of the blood draws is indicated as red filled circles.</p

Endogenous circadian rhythms in platelet function from cosinor analyses.

<p>Endogenous circadian rhythms in platelet function from cosinor analyses.</p

Independent influence of behavioral stressors on platelet function.

<p>WBA, platelet count, and plasma epinephrine were increased by each of the three stressors, with a (partial) recovery during recovery. In contrast, while the platelet surface markers showed a gradual increase across the approximately 3-h test battery, there was no consistent increase and recovery caused by the three stressors. Mental, mental stress test; tilt, passive head up tilt table test; exercise, cycle exercise test; B, baseline; S, stress test; R, recovery; x-axes, minutes from first blood sample within test battery; left y-axes, absolute values; right y-axes, data expressed as a percentage of each individual’s mean values across the forced desynchrony protocol; error bars, SEM; P-values, significance for effect of time across full stress test battery (9 time points); *, significance for change between consecutive samples (from baseline to stress test and from stress test to recovery). Note platelet ATP release is not shown (see above text).</p