Furthermore, no significant relationship (correlation coefficient: r < 0.3) was observed between beta 1 receptor occupancies of the drugs and the number of dreams. On the other hand, good relationships (r > 0.95) were observed between central and peripheral beta 2 or central 5-HT receptor occupancies and the number of dreams. These findings suggest that beta 2 and/or 5-HT receptor occupancy is superior to beta 1 receptor occupancy as an index for the sleep disorders.

Analysis of the subjective questionnaires showed that recollection of dreaming and awakening in the night was increased by the three lipophilic drugs, propranolol, metoprolol, and pindolol. These results confirm reports in the literature but are contrary to those expected from considering the effects of noradrenaline on sleep. Analysis of physiological records confirmed subjects' reports that waking was increased by the lipophilic drugs. Dreaming (rapid eye movement sleep, REM) was reduced, as predicted from knowledge of the effect of noradrenaline on sleep. Increased awakening leads to an increase in remembered dreaming which explains the otherwise paradoxical results.

These results confirm reports in the literature but are contrary to those expected from considering the effects of noradrenaline on sleep. Analysis of physiological records confirmed subjects' reports that waking was increased by the lipophilic drugs. Dreaming (rapid eye movement sleep, REM) was reduced, as predicted from knowledge of the effect of noradrenaline on sleep. Increased awakening leads to an increase in remembered dreaming which explains the otherwise paradoxical results.

Beta blockers have long been associated with sleep disturbances such as difficulty falling asleep, staying asleep, and insomnia. They have been shown to reduce the production of melatonin via specific inhibition of beta-1 adrenergic receptors. Melatonin is a hormone secreted by the pineal gland in the brain, and helps in maintaining normal circadian rhythms.6,20-21 People with hypertension already have a lower melatonin production rate than those with normal blood pressure.22