Effect of Oral Contraceptives, Menstrual Phase and Conditions on Alertness, Performance and Rhythms in Sleep Deprived Women

Effects of caffeine ingestion and exposure to bright light on alertness, performance, mood, and circadian rhythms melatonin, temperature in women during 48 hr of sleep deprivation were tested. In addition, influence of menstrual cycle phase follicular, luteal and oral contraceptive use on these measures was assessed. Finally, results of women and those of men tested previously under similar conditions were compared. Sleep deprivation decreased alertnessperformance and worsened mood but did not affect melatonin and temperature. Caffeine and bright light increased alertness and improved performance as well as reduced melatonin and enhanced temperature. Combining the latter two treatments was the most effective countermeasure to sleepiness. Menstrual phase affected alertness, performance, mood fatigue, and temperature with higher levels obtained in the luteal group. However, melatonin and temperature were highest in the oral contraceptive group. Circadian rhythms were evident in women across sleep deprivation, treatment group, menstrual phase, and oral contraceptive use. Caffeine delayed melatonin onset while bright light decreased the amplitude and increased the mesor of the temperature rhythm. In general, data of women were similar to those of men. The present investigation suggests that important additional research is needed.