An NIH medical sleep study observing breathing during sleep patterns have demonstrated that sometimes aspirin and indomethacin have negative effects on sleep in humans. Murphy PJ found that aspirin and ibuprofen disrupted sleep in comparison to placebo by increasing the number of awakenings and percentage of time spent in stage wake, and by decreasing sleep efficiency. After falling asleep, Ibuprofen also hindered the beginning of deeper stages of sleep. Murphy determined a relationship to direct and indirect consequences of inhibiting prostaglandin synthesis that induces deep sleep. Specifically, the study discovered decreases in prostaglandin D2, suppression of nighttime melatonin levels, and changes in body temperature.