Over 24 hours, sleep can be organized into one block, called monophasic, or multiple blocks knowns as biphasic or polyphasic sleep. Little is known about variation in organizational patterns of sleep in humans, but it is expected that monophasic sleep is present in a majority of healthy adults across the globe, with some cultures historically holding habits of napping during the day (a biphasic pattern).
Animal studies suggest great diversity in sleep patterns between species. Given the limited knowledge on the topic, the best type of sleep pattern is the one that ensures you get adequate sleep duration and best possible quality of sleep, achieved with either a single sleep episode (monophasic pattern) or with more than one (biphasic or polyphasic).
Biphasic and polyphasic sleep patterns are present in 7% and 1% of the evaluated population, respectively. An ability to fall asleep during the day can be the result of a genetic predisposition (i.e. morning person or night owl) the latter of which is found to be more frequently associated with chronic sleep deprivation. If this is the case, then a biphasic sleep pattern can be viewed as an adaptation to get desired amount of sleep.
