Biphasic sleep - are two sleep phases enough?

What is biphasic sleep?

Biphasic sleep is a form of polyphasic sleep where, instead of the traditional 7-9 hours of continuous sleep, the day is divided into two separate sleep phases. Typically, it includes a longer nighttime sleep (about 4.5 hours) and a shorter nap (around 1.5 hours) during the day, totaling about 6 hours of sleep per 24 hours. Another approach involves dividing night sleep into two segments - the first and second sleep.

Is biphasic sleep healthy?

Biphasic sleep is considered a healthier form of polyphasic sleep because it allows the brain to enter the restorative nREM phase. However, even though it is less extreme than other polyphasic patterns, traditional monophasic sleep is generally regarded as healthier today. Humans have evolved to adapt to a continuous sleep cycle, so it's wise to consult a doctor before switching to biphasic sleep to rule out any potential health concerns.

Is segmented sleep healthy?

Yes, segmented or polyphasic sleep - including the biphasic pattern - can be practiced and may be relatively safe if the body properly adjusts to the new rhythm. Biphasic sleep is the mildest version, involving one longer sleep period at night and a short nap during the day, or two distinct nighttime phases.

Why do people sleep biphasically?

Historically, biphasic sleep was a natural rhythm for humans, especially before the industrial age when artificial light was not present. People would often split their night’s rest into two periods, with an active break in between. Today, some opt for biphasic sleep due to potential benefits such as better recovery, improved focus, productivity, and greater time flexibility - especially under demanding lifestyles. Still, it’s not suitable for everyone.

How to feel rested in a short time?

To feel rested even with less sleep, the key is quality over quantity. The body needs complete sleep cycles that include deep nREM sleep and uninterrupted REM phases. Even shorter sleep can be restorative if it's regular, aligned with your body's natural rhythm, and occurs under proper conditions. The right mattress, pillow, and a healthy sleep environment also significantly impact restfulness.