Polyphasic sleep means sleeping in more than two distinct bouts within a 24‑hour period. It contrasts with monophasic sleep (one consolidated nocturnal block). Biphasic sleep has two bouts (typically a main sleep plus a nap). Online interest has grown among biohackers, entrepreneurs, and shift workers, but polyphasic sleep remains rare and controversial in healthy adults.

Reported/claimed upsides include: more waking hours and perceived productivity; frequent refreshed periods from naps; faster entry into deeper sleep stages per nap and perceived sleep efficiency; better memory/learning via REM access; more lucid dreams; flexibility for unusual schedules (sailing, emergency response, shift work); historical/psychological notions of stress regulation via segmented nights. Evidence is largely anecdotal and not generalizable.

Controlled data are limited and short-term. Dropout rates on extreme schedules are high; participants commonly report fatigue, mood changes, cognitive decline, and social disruption. Consensus reviews conclude: no scientific evidence supports polyphasic schedules as safe/sustainable for healthy adults; heavy fragmentation/restriction tends to impair cognition, mood, hormones, memory, and may raise chronic disease risks.

Anecdotes suggest frequent naps might increase dream awareness/recall, drawing analogies to WBTB techniques. Empirical support is inconsistent and limited; fragmentation and possible REM reduction may impair dream richness over time.

Monophasic: consolidated 7–9 h night sleep; better circadian alignment; intact deep sleep/REM cycles; strong long-term health/support; socially compatible.
Polyphasic: 2–6+ segments; frequent circadian misalignment; fragmented SWS/REM; adaptation difficult with higher dropout; associated with risks; potential extra waking hours but often lower quality and social fit.

Sleep organizations and clinicians caution or discourage lifestyle polyphasic sleep. Napping can mitigate acute sleep loss in constrained settings (e.g., shift work, space/military), but aim remains ~7–9 h total for adults. If anyone experiments, do so cautiously, short-term, with self-monitoring and medical input.

For most adults, monophasic (or at most biphasic) sleep aligned with circadian rhythms and totaling 7–9 hours is safest and most effective. Extreme polyphasic schemes (Uberman, Dymaxion) rarely sustain benefits and often incur sleep debt and health/performance costs. Everyman (core + naps) may be temporarily workable for a few, but long-term viability is doubtful.