Age, sleep and irregular workhours – a field study with electroencephalographic recordings, catecholamine excretion and self-ratings

Abstract

Day sleep (after night work) and night sleep (after day work) were studied in 2 groups of locomotive engineers aged 25-35 and 50-60 yr, respectively. All recordings were made in the homes of the subjects. For both groups day sleep was reduced by .apprx. 3.3 h, mainly affecting rapid eye movement sleep and stage 2 sleep. Diuresis and the excretion of noradrenaline [norepinephrine] increased during day sleep. The ratings of sleepiness were higher after night work. Several indices of disturbed daytime sleep correlated significantly with catecholamine excretion. Older subjects had relatively more stage shifts, awakenings, stage 1 sleep, a higher diuresis and a higher noradrenaline excretion during day sleep. Night work was detrimental to sleep and negative effects were exacerbated by increasing age.