Dose‐related sleep disturbances induced by coffee and caffeine

Abstract

In a 13-night sleep laboratory study, each of 18 normal young adult males twice received 1 cup of warm water, 1-, 2-, and 4-cup equivalents of regular coffee, a 4-cup equivalent of decaffeinated coffee, and a 4vcup equivalent of caffeine. All beverages were administered 30 min before bedtime according to a balanced Latin-square design. Regular coffee produced dose-related changes in most standard electroencephalogram-electrooculogram (EEG-EOG) sleep parameters, and the 4-cup equivalents of regular cartee and caffeine produced equivalent effects. Decaffeinated coftee had no effect. Regular coffee and cqffeine caused rapid eye movement (REM) sleep to shift to the early part of the night and stages 3 and 4 sleep to shift to the later part. Coffee also produced dose-related changes in several subjective estimates of sleep characteristics. These results suggest that coffee and caffeine may be used in normal subjects to induce symptoms mimicking those of insomnia. Such a tool should promote further understanding of insomnia.