Circadian rhythm stage affects many outcomes, including those of mental aging.
Estimations of 1 minute ~5 times/day for a year, 25 years apart, by a healthy male biomedical scientist (RBS), are analyzed by the extended cosinor.
Cycles of a half-week, a week, ~30 days, a half-year and a year, in self-assessed 1-minute estimation by RBS between 25 and 60 years of age in health, are mapped for the first time, compared and opposite effects are found. For RBS at 60 vs at 25 years of age, it takes less time in the morning around 10:30 (P < 0.001), but not in the evening around 19:30 (P = 0.956), to estimate 1 minute.
During the intervening decades, the time of estimating 1 minute differed greatly, dependent on circadian stage, being a linear decrease in the morning and increase in the evening, the latter modulated by a ~33.6-year cycle.
Circadian and infradian rhythm mapping is essential for a scrutiny of effects of aging. A ~30-day and a circannual component apparent at 25 years of age are not found later; cycles longer than a year are detected. Rhythm stages await tests as markers for timing therapy in disease.