Imagine sleeping for just two hours a day and feeling as refreshed as you would after a full night’s rest. It sounds tempting, but can a few short naps really replace a night’s sleep?

So-called polyphasic sleep schedules regularly attract attention online. The most extreme versions involve dividing just two hours of sleep into several short naps across a 24-hour period. Supporters sometimes claim that this leaves them with more time and energy. However, these claims are not supported by reliable evidence.

Sleep patterns change throughout life. Babies sleep in several periods across the day and night, while adults usually have one main sleep period. Some adults also take a daytime nap. These differences do not mean that adults can train themselves to need dramatically less sleep.

What are the different sleep patterns?

Monophasic sleep

Monophasic sleep means having one main sleep period in each 24 hours, usually at night. The amount of sleep needed varies from person to person; eight hours is not a fixed requirement for everyone.

Biphasic sleep

Biphasic sleep involves two sleep periods, such as a main sleep at night and a nap during the day. The term describes how sleep is divided, rather than how much sleep someone needs overall.

The Everyman schedule

The Everyman schedule combines a shortened main sleep period with several naps. Different versions are discussed online, with some reducing total sleep to only a few hours a day. These schedules should not be mistaken for established recommendations for healthy sleep.

Dymaxion

The schedule commonly called Dymaxion consists of four 30-minute naps spaced across 24 hours, adding up to just two hours of sleep. This is a description of the proposed pattern, not evidence that it provides enough rest.

Uberman

One commonly described version of the Uberman schedule involves six 20-minute naps across 24 hours, again totalling two hours. Like Dymaxion, it severely restricts total sleep time.

The theory behind the claims

Some supporters suggest that an adjustment period allows the body to enter rapid eye movement (REM) sleep more quickly, making sleep more efficient. However, there is no reliable evidence that a few weeks of practice can make two hours of sleep sufficient.

REM sleep is only one part of normal sleep. Non-REM sleep, including deep sleep, also has important functions. Maximising one sleep stage is not an established substitute for getting enough sleep overall.

What does the evidence say?

It is inaccurate to say that scientists have not investigated polyphasic sleep. A published expert review found no evidence of benefits from schedules that substantially reduce total sleep and identified concerns about health and performance.

Sleep deprivation can affect alertness, concentration, mood and reaction times. Feeling that you have adapted does not necessarily mean your performance has recovered. Persistent exhaustion should not be treated as a hurdle to push through.

Can people maintain these extreme schedules?

Personal accounts online cannot establish whether a sleep schedule is safe or effective. They may lack reliable measurements of actual sleep, daytime functioning and longer-term effects.

The body’s internal clock also influences when we feel sleepy and alert. Light and darkness help regulate this rhythm, so sleep cannot simply be rearranged without regard to timing.

Some endurance events involve fragmented sleep because competitors have limited opportunities to rest. That does not demonstrate that severe sleep restriction preserves performance or is suitable for everyday life.

Is one sleep period always best?

There is no need to label every sleep pattern as either “natural” or “unnatural”. Sleep timing can reflect biology, age, culture, working hours and individual circumstances. A daytime nap alongside adequate night-time sleep is different from deliberately cutting total sleep to two hours.

Historical accounts of divided sleep do not establish that extreme modern nap schedules meet adults’ sleep needs.

What should you take away from this?

Extreme schedules such as Dymaxion and Uberman promise extra waking hours, but there is no reliable evidence that they deliver adequate rest. Their rigid nap times can also be difficult to fit around work, family and social commitments.

A more useful priority is to allow enough time for sleep and maintain a regular routine that suits your needs. If you regularly struggle to sleep or feel excessively sleepy during the day, speak to a healthcare professional.

More time awake is not necessarily more time well spent. Cutting back on essential rest can leave you less able to enjoy or make use of those extra hours.